MOLINE, Ill. - The countdown is on until a rare total solar eclipse, and Quad Cities astronomy club is preparing for the once in a lifetime experience.

August 21st will be the first time in 99-years that day will turn to night from coast to coast.

Al Scheidler is president of Popular Astronomy Club in Moline. He says stargazers have been planning to view this eclipse for years.

"They aren't occurring where there are large populations. This time we're lucky enough to have them go right straight through the center of the United States."

A total solar eclipse is when the sun, moon and earth align perfectly with each other, leaving some areas of the united states in the dark for a few minutes during the day.

"Popular Astronomy Club" will be hosting a viewing party at the Moline public library the day of the eclipse.

The group owns a mobile observatory - one of only two in the U.S.

The "path of totality" is the 3000 mile long journey the eclipse will travel, starting in Oregon and ending in South Carolina.

In the Quad Cities, you'll be able to see about 91 percent of total eclipse.

Experts say you should use proper equipment to view the eclipse to avoid permanent eye damage.

Local 4 News chief meteorologist, and eclipse super-fan, Andy McCray, is hoping for clear skies.

"The one thing we can't control though is the weather. We do need clear skies. If it's a cloudy, overcast day it's not going to be nearly as exciting."

If you miss the total eclipse next month, another total solar eclipse will pass through the U.S. in 2024, on a slightly different route.

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Local Astronomy Club preps for Total Solar Eclipse - OurQuadCities

We in Maine are more fortunate than many realize. Maine enjoys dark skies, undiluted by artificial light. During nights when the atmosphere is stable and fog or cloud cover doesnt interfere, a person almost anywhere in Maine can look up and clearly see the Milky Way, our home galaxy.

It is sad to note that in so many places in our country, people live their lives out without ever seeing the Milky Way. But here, we can revel in the sight of a river of stars running across the sky, far too many to count, and so numerous as to defy our ability to fully appreciate them.

And within the Milky Way, we can plainly see a ribbon of black, separating this star river. Its called the Great Rift and it effectively blocks out everything behind it, at least from our point of view here on Earth.

Pareidolia, the phenomenon responsible for people's seeing images in clouds and the man in the moon, also works for us as we try to visualize the various geometric, random and fanciful shapes we see in the night sky.

Some of these shapes are, indeed, constellations. In 1930, the International Astronomical Union chose 88 official constellations. These include every star in the heavens. And while a star may belong within the boundaries of a certain constellation, it may not be part of any recognizable pattern.

Some easily recognized patterns are not constellations, but are called asterisms. Prominent among these are The Big Dipper, an asterism in Ursa Major; The Summer Triangle, formed of stars belonging to three different constellations; and The Northern Cross, a group of stars in the constellation Cygnus, the Swan.

Add to this the planets and deep-sky objects, such as star clusters, galaxies and nebulae, and we have enough viewing to satisfy the most eager amateur astronomer.

Here, then are some suggestions for how, when and where to begin this exciting journey into the nighttime skies.

1. Naked-eye viewing

You dont need optical aids to enjoy the heavens. Your eyes can take in enough to fill an entire evening under the stars. The first goal here is to learn to recognize as many constellations as possible. To do this, either download an astronomy app for your smartphone, or send for a planisphere. A planisphere is a device that looks like a wheel, with numbers on the edges. Another wheel, movable and attached to the larger circle, can accurately indicate all constellations within your sphere of view. Just align the dates and numbers (its easy, and besides that, directions are included) while holding the planisphere up to the sky and you can begin to nail down one constellation after another.

Planispheres are available from astronomy shops everywhere, as well as from many gift shops. Amazon sells several good-quality planispheres at very reasonable prices.

Its hard to describe the feeling of accomplishment when, after a few nights, you can accurately name most of the constellations in view.

2. Binocular viewing

The next step in your development as an amateur astronomer is to begin using binoculars to view the heavens. Binoculars are wonderful for wide, or spread-out objects. In fact, most people use binoculars in conjunction with their telescopes. I like to locate hard-to-find objects first with my binoculars and then view them with my telescope.

With the possible exception of opera glasses-style binoculars, any old set of binoculars will work for stargazing. Most full-size binoculars can do the trick for amateur observers. Of these, 10 X 50 is the best choice for the casual astronomer. These numbers, by the way, refer first to magnification and second, to field of view. The larger the second number, the greater the field of view.

When stargazing with binoculars, it helps to steady them by sitting in a folding chair and bracing your elbows on your hips or even on the arm of the chair. This helps to cut down on wobble. It is nearly impossible to hold binoculars steady when standing up. That is, unless you use IS, or image-stabilized binoculars.

These IS binoculars use electronic gyroscopes to hold an image solidly with no shake or wobble. Just focus on the object you wish to view and then hold down a button and the IS feature will kick in. People trying these for the first time are always amazed at the difference between regular binoculars and IS binoculars. In fact, IS binoculars impart the effect of an increase in magnification. The steadier the picture, the better you can see fine details.

Such binoculars are pricey, but they offer the best and steadiest view possible. Besides that, they are good when viewing terrestrial objects from boats or motor vehicles. And for bird-watching, nothing beats them.

My personal IS binoculars, a 10 X 30 set made by Canon, are worth every penny I paid for them. Some people use their IS binoculars as much as they do their telescopes because binoculars need no lengthy setup and are ideal for checking out the sky when time is limited. Just remove the lens caps and begin viewing.

If all you have, however, is an old set of binoculars stowed away in the closet, by all means use them. Any binoculars are better than no binoculars.

3. Tricks of the trade

Some little things will help you to see better when stargazing. First, it pays, if possible, to let your eyes adapt to darkness by staying outside for 20 minutes before beginning your serious viewing.

And if you need to read your planisphere or sky chart, make sure to use a red light. Red light does not harm night vision. You can buy special astronomy red lights, but the simplest way is to just take a regular flashlight and place some red cellophane over the lens.

Sometimes you know you are viewing the object you seek, but cannot see it clearly. This happens, for instance, when viewing double stars, stars that are either bound together by gravity or stars that are not at all close together but appear that way from our point of view. These are called optical doubles.

The way to make a reluctant twin to a brighter star suddenly stand out is to look at it with averted vision, that is, from the periphery of your eye, rather than viewing it straight-on. It helps to blink once in a while, too. This helps to steady your eyes focus.

4. Telescopes

Telescopes come in several types: reflectors, refractors, Cassegrain reflectors and Catadioptric telescopes. The easiest to use are refractors, but they are the most expensive per inch of aperture. I use a 4-inch refractor made by Explore Scientific, and the ease of setting up makes it the best go-to scope available.

However, the best bang for the buck award goes to Newtonian reflectors. These use mirrors to bounce an image into the eyepiece. It is possible to get a decent-quality tabletop reflector for around $100. And, of course, reflectors range in size from 4-inch models all the way up to 18-inch behemoths. For beginners, a 4-inch or 6-inch reflector will give plenty of viewing pleasure for years to come.

5. Upcoming events

July sees many interesting chances for stargazers. First, for early risers, the Pleiades, the famous star cluster also used as the emblem for Subaru cars (Subaru means "Pleiades" in Japanese), are halfway up the eastern sky about 45 minutes before sunrise.

Also, the planet Venus shines brightly below and to the left (east) of the Pleiades.

Then, at sunset, on the nights of July 24-25, Mercury shines a bit below and to the right (west) of the crescent moon.

And on July 28, the gas giant planet Jupiter, along with its several satellites, sits just below the waxing moon. Look to the west-southwest one hour after sunset.

The moon itself makes a suitable target as well. Just remember that the best lunar viewing occurs during the crescent stage. Then, images around the terminator, or line of darkness, are stark and contrasty.

Stargazers like company, and many come together for the Acadia Night Sky Festival. For more info on this annual event, visit acadianightskyfestival.com.

For now, then, happy stargazing and clear skies to you.

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This summer, try amateur astronomy - By Tom Seymour - Rockland ... - Courier-Gazette & Camden Herald (subscription)

The eVscope allows amateur astronomers to crowd source their observations (Credit: Unistellar Optics)

The SETI Institute, in partnership with French startup Unistellar, wants to up the game for amateur astronomers by marketing a new small telescope that acts as a crowd-sourcing instrument. The Unistellar eVscope is a computerized 4.5-in (11.4-cm) refracting telescope that combines advanced optics with networking technology that allows amateurs to work together on observation campaigns feeding a central database.

Small, portable astronomical telescopes are great fun, but after looking at the Moon and the four closest planets, it starts to get a bit samey. The problem is that small scopes have very limited light-gathering capabilities and to do any serious work, like sky photography, they need complex equatorial mounts so they track the stars through the night.

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The eVscope is designed to change that with a lightweight, portable design and a trio of features that give it the capability of larger telescopes and the ability to join forces with other eVscopes.

The first of these is Enhanced Vision, which uses light amplification technology to produce brighter, more colorful images in sharp focus, similar to what one sees in wider aperture instruments. Though this does come at the price of a few seconds delay as the eVscope collects and processes the light.

The second feature is Autonomous Field Detection (AFD), which replaces the traditional equatorial mount with much simpler two-axis azimuth mount. Using GPS and connected to a database of tens of millions of celestial objects, it can not only automatically align with a specific object, but can also automatically identify and name what it's pointed at.

But the party piece of the eVscope is the Campaign Mode. Developed by the SETI Institute, it allows groups of amateur astronomers to work together on coordinated projects. When activated, the Campaign Mode collects image data from various eVscopes and transmits it the SETI Institute headquarters in Silicon Valley. There the images form part of a growing data repository for specific objects annotated by date, time, and location. According to Unistellar, this could be used as part of a network looking out for potentially dangerous asteroids.

(L to R)Franck Marchis (CSO and SETI Institute astronomer), Arnaud (Chairman and CTO), Laurent (CEO) and the demo prototype shown at Aix-en-Provence, France in June 2017 (Credit: Unistellar Optics)

"Unistellar's eVscope is a powerful new instrument that can generate important data about transient events of interest to astronomers, including supernovae, near-Earth asteroids, and comets," Franck Marchis, Senior Scientist at the SETI Institute and Chief Science Officer at Unistellar. "There is much to be gained from continuous observations of the night sky using telescopes spread around the globe, and by coordinating observations and sending alerts to users in order to study faint objects like comets or supernovae."

A prototype of the eVscope is currently undergoing testing at the SETI Institute while the partners seek funds to develop a new commercial version aimed at the mass market in preparation for a presale crowdfunding campaign later this year.

The video below demonstrates the eVscope technology.

Source: SETI Institute

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Networked eVscope would crowd-source amateur astronomy - New Atlas

Oh, I love stories like this: Citizen scientists people who are not necessarily trained scientists but are enthusiastic and eager to take part in scientific research have discovered a brown dwarf near the Sun. They examined data taken by an orbiting observatory and found the little beastie right at the edge of the telescopes detection capabilities.

OK, first: Simply put, a brown dwarf is an object that is in between the mass of a planet and a star. Thats really too simply put; were talking about a rich and diverse class of objects, every bit as varied and interesting as planets and stars themselves (for that reason, I think its unfair to call them failed stars, as some do; they are their own thing, and fascinating in their own right). You can find out a lot about them by watching my brown dwarf episode of Crash Course Astronomy:

Being warmish, brown dwarfs tend to emit most of their light in the infrared part of the spectrum, outside the color range our eyes can see. But we can build detectors that are sensitive to infrared, attach them to telescopes, launch them into space, and sweep the sky to see whats out there.

Astronomers have done this, many times, including with the wonderful Wide-field Infrared Survey Explorer, or WISE, for several years starting in 2010. It looked in four different wavelengths (colors) of IR light, creating a vast catalog of objects in the sky over three-quarters of a billion of them.

A lot of those objects were brown dwarfs. They were found in two ways: Either by their colors (they tend to emit light at a specific IR color, making them stand out in WISE images) or by their motion. Brown dwarfs are extremely faint, so we only see ones that are relatively nearby the Sun (like, out to 100 light-years away or so). Because theyre close, their motion in space as they orbit the galaxy means we can see them move over time its just like nearby trees seem to whiz past you when youre in a car, when more distant object appear to move more slowly. Finding moving brown dwarfs is hard; theyre faint and look little more than blips in the images. This makes automating the search difficult (computers are easy to fool). But the human eye is good at seeing such things! And such a task doesnt need a lot of training, either.

Thats why the folks at Zooniverse decided to take this on. This is a group of astronomers and researchers who figured out that non-scientists can not only participate in scientific research but also give a meaningful contribution to it as well. They collect data in the public domain (quite a bit of astronomical data) and present them in such a way that people can analyze them through simple tasks. For example, Galaxy Zoo asks people to identify spiral galaxies and determine whether the arms open clockwise or counterclockwise. Simple, fun, and oddly addictive, in fact. Ive identified hundreds of galaxies myself there, and theyve published quite a few papers on the results.

They did a similar project with the WISE images. Called Back Yard Worlds, it blinks four images from WISE observations taken of the same part of the sky at different times. The images have been processed a bit, subtracting one from another, so that fixed objects like stars and galaxies are suppressed, hopefully leaving behind moving targets. Your task: Look for the things that change. Its not easy; I just tried it and there are lots of things that can fool the eye. But if enough people look at enough images, things turn up.

And something did: On February 1, 2017, less than a week after the launch of Back Yard Worlds, a user spotted what looked like a slowly moving object. It appears as a dipole,a shifting spot of black and white due to the way the images were subtracted from one another. Two days later, another user spotted it, then three more not too much after that.

Clearly, the object was real. At this point, professional astronomers used NASAs Infrared Telescope Facility, a 3-meter telescope in Hawaii, to observe the object, and they quickly determined it was indeed a brown dwarf.

It has been dubbed WISEA J110125.95+540052.8 (after its coordinates in the sky), and its about 110 light-years away. Not much is known about it except that it has a spectral type of T5.5, meaning its an intermediate mass and cool brown dwarf (with a temperature of very roughly 650-1250C, much cooler than the Sun).

Another reason is that I love that the public gets a chance to get their feet wet with real data. This isnt some simulation, or some overly simplified homework assignment.This is real science, with real data, that could have a real impact. And in this case, it did, and will continue to do so. Its wonderful that non-scientists, laypeople, can have the chance to participate in that.

And finally, theres the potential of this. There is a lot of data out there. Did you know that all Hubble data older than one year is available through an archive? Its not like you can just grab it and discover strange, new worlds unlike Zooniverse, CosmoQuest, and other citizen science projects, theres a huge overhead and learning curve with Hubble data but there are thousands upon thousands of images and spectra just waiting to be analyzed, far more than the scientists who took them could ever hope to process.

And thats just Hubble. Cassini, the Mars rovers, Juno there are dozens of observatories and spacecraft with data just sitting there. What treasures lie within? What discoveries patiently await us? What new kinds of objects, old objects behaving in new ways, new phenomena, have already been captured by these eyes on the sky biding their time until human eyes gaze upon it?

This idea is thrilling. The whole Universe is out there, and you can be a part of unveiling it.

Tip o the dew shield to Astrobites.

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'Citizen scientists' find a nearby brown dwarf - SYFY WIRE (blog)

This artists rendition shows a possible design of a potential successor to the Hubble Space Telescope. This conceptual mission, called the Advanced Telescope Large-Aperture Space Telescope (ATLAST), is similar in approach to one of several observatories currently under study by astronomers. Credit: NASA

Scientists outlining four concepts for a powerful new space telescope that could launch in the 2030s this week said improvements in optics, detectors and access to huge new rockets like NASAs Space Launch System could revolutionize the way astronomers observe potentially habitable planets, black holes, and the earliest galaxies in the Universe.

It is likely NASA will only be able to afford one of the four proposed flagship observatories, and the space agency will take the advice of an independent review by the National Research Council in 2020 on which type of telescope should receive highest priority.

NASA launched studies last year to look into the scientific benefits, costs and technical challenges of four astronomy missions:

Four teams will produce interim reports on the four mission concepts by the end of this year, then publish their final reports in 2019 as a resource for scientists on the next astrophysics decadal survey panel in 2020, which will rank priorities for future NASA astronomy missions.

The studies will offer only a roadmap for NASAs next leap in astronomy, and officials say any telescope that does reach the launch pad in the 2030s will likely look much different from the concepts currently under investigation. Tough decisions on engineering constraints and cost caps remain ahead, but NASA it needs to start preparing now given the long life cycles of such missions.

The space agency typically follows the decadal surveys advice.

The two last decadal surveys prioritized infrared astronomy. A report from the National Research Council in 2001 led to the approval of the James Webb Space Telescope, which is due for launch next year, and the 2010 decadal survey recommended NASA pursue a mission which became the Wide-Field Infrared Survey Telescope, or WFIRST, scheduled for liftoff in the mid-2020s.

NASA expects to have funding for another advanced flagship-class, multibillion-dollar great observatory to launch some time in the 2030s, once the agency puts behind major spending on JWST and WFIRST.

Astronomers expect breakthroughs with any route prioritized in the next decadal survey.Cost estimates on each of the four mission concepts will come later to help inform the decadal surveys decisions.

The LUVOIR mission concept would be a true successor to Hubble, covering much the same range of wavelengths as NASAs most famous long-lived orbiting telescope. The mission outline is similar in capability to the High Definition Space Telescope, a super-Hubble proposed by astronomers in 2015, and the Advanced Technology Large-Aperture Space Telescope, known by the apt acronym ATLAST.

With LUVOIR, we would be able to study in much greater detail how galaxies assemble their stars, said Debra Fischer, a professor of astronomy at Yale University who co-chairs the LUVOIR study team. The killer app for LUVOIR is actually being able to coronagraph and image pale blue dots around some of the nearest stars, and then once we have those images, to be able to take spectra of them.

Instruments on a mission like LUVOIR could look for signs of water vapor, oxygen, methane and other gases in alien atmospheres that might be habitable, Fischer said in a presentation Thursday to NASAs Astrophysics Advisory Committee.

The size of an observatory like LUVOIR hinges on the volume of launchers that might be available in the 2030s. A primary mirror with multiple segments, similar to the design of JWST, would be folded up for liftoff.

Commercial rockets like United Launch Alliances Delta 4-Heavy and SpaceXs Falcon Heavy come with standard fairings around 5 metres (16 feet) in diameter, while NASAs more costly but more powerful Space Launch System could accommodate payloads as wide as 8.4 metres (28 feet) by the late 2020s.

The dimensions of a telescope like LUVOIR are bracketed by the capabilities of the Delta, Falcon and SLS rocket options, although the Delta 4 rocket is likely to be retired in favor of ULAs next-generation Vulcan booster by the time such a mission is ready for liftoff.

Another rocket that might give future telescopes rides into space is the New Glenn, a methane-powered booster in development by Blue Origin, the space company founded by Amazon.coms Jeff Bezos. The privately-operated New Glenn could make its debut launch by 2020, and it can loft payloads as wide as 7 metres (23 feet).

A rule-of-thumb for deployable telescopes is that a 9 or 10-metre (30-33 foot) primary mirror could tuck inside standard Delta 4-Heavy or Falcon Heavy fairings. The Space Launch Systems nose cone could fit a 16-metre (52-foot) multi-segment mirror folded up origami-style.

None of the proposals under study would need in-space assembly by astronauts, but Fischer said robotic or human servicing might be possible for a mission like LUVOIR.

Fischer identified launch vehicle limitations as one of the top technological risks for the LUVOIR concept, which would likely be sent to an observation post at the L2 Lagrange point a million miles (1.5 million kilometres) from Earth in the direction away from the sun. Other question marks include the readiness of ultraviolet mirror coatings, infrared detector technology, and ultra-stable opto-mechanical systems, Fischer said.

While LUVOIR would be a general purpose observatory best geared for large-scale galactic, dark matter and statistical exoplanet surveys, the smaller HabEx concept would emphasize exoplanet research, focusing on a few nearby stars known to host potentially habitable worlds.

Rather than statistical-based as LUVOIR is, were more exploration-based, said Scott Gaudi, a professor of astronomy at Ohio State University who co-chairs the HabEx study. We want to study nearby planetary systems and just figure out what theyre like.

HabEx could probe up to a dozen potentially Earth-like planets around stars in the suns neighborhood, Gaudi said Thursday.

Our goal is to detect and characterize a handful of potentially habitable planets, and then search for signs of habitability and biosignatures on those planets, he said.

A mission based on the HabEx concept could perhaps distinguish between analogs of Venus, Earth and Mars, which all lie within the suns habitable zone, a region where liquid water could persist on a planets surface under the right conditions. But only Earth has an environment ripe for life.

Gaudi said his team will present at least two HabEx mission concepts to the decadal survey panel, one with a single-piece 4-meter (13-foot) primary mirror with nearly twice the collecting area of Hubble, and another with a 6.5-metre (21-foot) segmented mirror comparable to JWSTs.

HabEx will need help resolving the faint light coming from exoplanets, which can be more than a billion times dimmer than the light coming from their host stars.

One option is to launch a separate starshade, a petal-shaped spacecraft tens of metres (up to 100 feet) wide that would keep formation via laser navigation tens of thousands of miles from a telescope such as HabEx. The idea is to block bright starlight, revealing planets lurking nearby.

A tiny coronagraph embedded inside the telescope could also help detectors register exoplanets, allowing instruments to break up the light into spectra like a prism, telling scientists about the chemicals and gases in their atmospheres.

No space telescope has ever flown with a starshade, and coronagraphs aboard current-era observatories like Hubble and JWST are unable to see planets close to their stars, where temperatures might be favorable for life. The WFIRST mission might carry a coronagraph that works in concert with deformable mirrors and ultra-low-noise cameras, yielding views of potentially habitable worlds, but HabEx would have much better sensitivity thanks to a bigger mirror.

Two other concepts under scrutiny would scan the infrared and X-ray universe.

The Origins Space Telescope will probe the births of stars and planets in the Milky Way galaxy, trace the evolution of galaxies throughout cosmic history, seeing through thick envelopes of dust to study regions invisible to other telescopes.

Building on discoveries expected from JWST and WFIRST both infrared observatories the Origins Space Telescope would be sensitive to lower-energy far-infrared light, a part of the spectrum that reveals some of the coldest parts of the Universe.

Beyond JWST, we will still have questions, said Asantha Cooray, a professor at the University of California, Irvine, and co-chair of the Origins Space Telescope study. We will not how those stars came to be. We want to know and we want to understand what mechanics produce what stars.

The far-infrared telescope could be as big as 9 metres (30 feet) in diameter, Cooray said Thursday, a size limit set by the volumes of Delta and Falcon rocket fairings.

The Origins Space Telescope could image pockets of tenuous gas and dust in the interstellar medium, the area between stars. Clumps of cold matter glow in far-infrared light.

We still do not have a probe for the interstellar medium, and thats where the Origins Space Telescope comes in, Cooray said.

He said the infrared observatory would also make observations of exoplanets like LUVOIR and HabEx, and potentially detect biosignatures.

Our science case is broad and covers a wide range of topics, Cooray said. Our aim is to provide a factor of maybe between 5,000 and 10,000 improvement in sensitivity relative to the best we had with (ESAs) Herschel. Thats a large number.

Cooray said a mission based on the Origins Space Telescope approach would have have a factor of 30 better sensitivity than JWST, not just because of its size but because mechanical coolers would chill the observatorys detectors below 5 Kelvin (minus 450 degrees Fahrenheit), just above absolute zero. That will make the future telescope capable of seeing frigid parts of the Universe.

We are not trying to take images and improve a little bit, he said. We are really talking about revolutionary astronomy with the Origins Space Telescope.

Astronomers scoping the next potential X-ray telescope are working on the Lynx mission concept.

Billed as a machine for looking back in time to the first billion years after the Big Bang, the Lynx observatory would seek to find the universes first black holes and galaxies. Theories currently govern astronomers understanding of this era, when light from the first stars could escape through an absorbing haze of hydrogen left over from the Big Bang, but Lynx could add hard data to the equation.

We have decided what kind of observatory Lynx should be, how big that observatory should be, said Alexey Vikhlinin, astrophysicist at the Harvard-Smithsonian Center of Astrophysics and co-chair of the Lynx study. We have identified plans for the X-ray optics. We are in the process of making a decision on the (proposed) instrument suite.

Vikhlinin said Thursday the Lynx team has identified the drivers of galaxy formation and the dawn of black holes as two key pillars of the would-be mission.

Lynx would also map the distribution of matter in the cosmic web, the voids, clusters and filaments that tie together the Universe. Another target would be the halos of material surrounding galaxies brightest star-filled regions, which astronomers believe plays an important role in a galaxys birth.

Scientists say the Lynx mission would offer a leap in sensitivity two orders of magnitude over Chandra, which launched in 1999, and the planned European-led Athena X-ray telescope due for liftoff in 2028.

But big advances in technology are required to make a mission like Lynx a reality.Vikhlinin said high-resolution lightweight X-ray optics is the area of most concern for us.

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.

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Study teams comb through NASA's wish list for new telescope - Astronomy Now Online

What made you want to write a book about Jill Tarter and her life?

I care a lot about the details of science and understanding the universe in traditional ways. Then I thought back to what had very initially excited me about astronomy and made me want to go into it and it was SETI and the big questions about SETI. The biggest one: Are we alone? How does life develop? What is our place in the universe? Then, I watched Contact when I was 12 and when it came out I was very obsessed with it. Then I started reading more and didn't quite realize that no one had written anything long about Jill. But I was like, Heres this woman whos really been around the whole time and I know has inspired a lot of people, especially around my age in astronomy. And all that existed are these scattered interviews with her and maybe its time someone did something bigger.

When did you first find out about Jill Tarter and her work with SETI?

Well I guess lets start with the fake Jill Tarter, because that was all I knew from the film. All I knew was fake Jill Tarter for a really long time. My family rented the movie Contact probably as soon as it came out on video. Yes, VHS. We watched it and Id never seen a movie that I cared about so much and was just like, wow. Id never heard of radio astronomy because I was 12. I didnt know that searching for extraterrestrials was this scientific pursuit that was more than science fiction. I was very enamored of this character, Ellie Arroway, who had dedicated so much of her life, her fake life to the search.

Then I studied astronomy in college and did an internship in Green Bank, West Virginia, where the first SETI search took place. It turned out all the other interns were similarly obsessed with Contact because [we] were the same age. So we watched it one night and my friend said, Hey, you know that is based on a real person. I was like, What? What are you saying right now? Thats not true. Thats crazy. But it was not crazy and it was true.

Something that really runs through the book is Jills consistent battle with sexism in her field. How important was it for you to translate her experiences to the reader?

It was really important for me to get across how much she had to go through to be a revolutionary figure in astronomy. Good and bad. Its great that she was able to withstand the challenges of having her high school guidance counselor tell her that girls didn't need to to take physics. After that, being the only woman in her college classes and having to do her homework by herself because she wasnt allowed on the boys side of campus. Something thats important and something that I think Jill didnt exactly realize until she was maybe in her late 20s or 30s was that thats a good thing, and we need people like that. But also that it shouldnt have to be that way. You shouldnt have to be a revolutionary to be a woman in science.

I think things changed for her when she went to a meeting in Washington, D.C., that brought together a bunch of women Ph.D.s and she realized they were all going through the same sexist struggles and were like, Thats ridiculous and its great that we did it. But we shouldn't have to and we should help each other instead of thinking, Well, I made it through, you can make it through.

I think thats the key because its 2017, no one should have to be a revolutionary to take part in any field.

One thing Jill and others in SETI have always battled is the idea that the search for extraterrestrial life is fringe, but really its a massive scientific endeavor. Do you think we will ever stop associating SETI with being on the outskirts of science?

I think that from the beginning of Jills career, a large part of what shes been trying to do is to convince people by showing them that science and engineering factors that go into whether or not theres extraterrestrial life. Like how stars form and how planets form and how microbial life develops and that all of those are pretty straightforward, traditional science topics that lead to extraterrestrials.

Theres been a struggle her whole career to convince people that its legitimate and they don't just sit around looking for UFOs and little green men. I dont necessarily think that it will ever be able to escape that.

What do you want readers to take away about SETI and what its like to be a part of the search?

I would say that it takes an incredible amount of dedication and passion to be a SETI scientist because theres not a lot of money. There is a lot of public ridicule. Its hard to get tenure at a university if youre studying it and you have to really want it. You have to really care about it. Its not just a throwaway, weird fringe hobby.

Is there a part of the book you especially enjoyed writing?

In the first chapter theres a section where shes telling me about being in high school. We spent a weekend at her cabin and Donner Lake just watching her and her husband interact in real time and observing what they have in their cabin. Which is, they have a bookshelf that has Vogue Sewing and the Project Cyclops report from NASA. Then I went on a couple of field trips with the interns they had at the SETI Institute up to the Allen Telescope Array.

In your year spending time with Jill, was there something you learned about her life that was especially surprising to you?

The most surprising thing to me was when you think of someone like Jill, whos been a leader in the field and such a public figure, that they were always meant to do this work. Thats just a nice story to tell yourself. But really, Jill kind of thought about extraterrestrial intelligence when she was very young. One time looking up at the stars she just thought, Huh, I think theres probably someone else on the other side looking back at me. Then she kind of left it alone until she was almost 30.

Has Jill ever talked about what its like being a role model for an entire generation of people?

She doesnt like to talk about it so much. She knows its true because every conference she goes to, someone between the ages of 20 and 40 comes up to her and tells her that. I think that she ... she hasnt actually told me so this is an inference, not a thing that I know for sure. Is that she is happy to be that person that she didnt have in her own life.

There were a few women astronomers that she could look up to, but no one who was doing the kind of work she was doing. So I think shes happy that other people can have that. But for the most part shes very focused and a very practical person. I think she probably thinks about it and then immediately puts it out of her mind and just goes on with her work. I think thats also what people look up to her dedication to her work. So its just a vicious cycle of being a role model for people.

I have to ask since you wrote a book about a SETI pioneer and its what inspired you to go into astronomy do you think were alone in the universe?

I dont know. Well, I will caveat what Im about to say by saying that the whole point of SETI is to answer that question with science and not with guessing and wondering. So if I thought I knew, I wouldnt have written a book about SETI because I would not care that much about the science. So I think its important to investigate it scientifically. That said, I think the universe is an extremely large place. The largest place. We know that it has so many planets now or so many planets that can possibly host life. I think just statistically it makes more sense to me that there would be life and even intelligent life than it does statistically to think, out of all of this stuff, were the one time this kind of evolution happened.

Originally posted here:

Making Contact: Jill Tarter and the SETI Search | Astronomy.com - Astronomy Magazine

It would take a dwarf planet-sized impactor to end all life on Earth.

Thats according to research published in Scientific Reports last week. The study looked at what it would take not just to end humanity, but to actually sterilize the entire planet of any life contained on it.

The calculations from a team at Oxford and Harvard Universities suggest you would need 6 x 1026 joules of energy far, far more than contained in our nuclear arsenal. With that much power, you could vaporize the oceans of Earth and sterilize the entire planet in the process by bringing all available water on the planet up to at least 212 degrees Fahrenheit (100 degrees Celsius) the boiling point of water.

In order to make a blast that size, you would need a big, big asteroid. According to Science Magazine, it would have to be the size of Vesta or Pallas, the second- and third-largest asteroids, respectively. Both those objects have diameters at around 310 miles (500km), about the minimum size for a dwarf planet. (Neither Vesta nor Pallas are round and thus arent considered dwarf planets.)

Thats a pretty big impact. Its also what you might need to rob tardigrades of every chemical they need to live. Tardigrades are tiny, hardy pond-dwelling creatures that can seemingly survive anything nature throws at them. They can even survive prolonged radiation exposure or drought, though not indefinitely.

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Ending all life on Earth would take a pretty big object | Astronomy.com - Astronomy Magazine

Many of us thrill to the breathtaking views of outer space permitted by telescopes and spacecraft. But dark matterthe force causing stars to move faster than their mass would allowposes a pesky problem: you cant see it. So Carly Snell, aided by the chair of BUs astronomy department, Tereasa Brainerd, is spending the summer writing computer code to analyze telescopic survey data of the heavens. One goal is to see if the orbits of actual galaxies match those in simulations of dark matter.

Snell doesnt go to BU; the physics major will be a senior this fall at North Dakota State University, and my department there does not have astronomy, she says. The National Science Foundations Research Experience for Undergraduates (REU) program provides aspiring astronomers like Snell the opportunity to pursue this research.

This summerBUs third participating in REUhas brought Snell and five other undergraduates from different universities to campus to help professors researching topics in astronomy and space physics. The latter get research help; the students have the opportunity to wet our feet a little bit in research that a lot of people wouldnt necessarily get at their home university, Snell says. (BUs own students get similar mentoring through the Universitys Undergraduate Research Opportunities Program.)

The REU program in the astronomical sciences includes 28 universities, observatories, museums, and other institutions, including BU. Here, the students enrolled in this summers program hail from the Universities of Kansas, Maryland, Michigan, North Dakota State, Rochester, and Wisconsin. They spend 10 weeks on campus, studying topics from the earth to the galaxies, says Merav Opher, a College of Arts & Sciences associate professor of astronomy and director of BUs REU program.

Each student is matched with a specific research project so that they can work closely with specific researchers. Students receive a stipend as well as financial support for food, lodging, and airfare.

REU teaches both science and career development; here, Mark Kornbleuth (CAS13,16, GRS20), a research fellow in the astronomy department, offers resume-writing tips to students Carly Snell, left, and Genevieve Schroder.

Mark Hubbert, a rising senior at the University of Maryland, is helping Ophers effort to confirm her new model of the shape of the suns magnetic field, the heliosphere. The model is pretty rock-solid from a theoretical perspective, he says, but hasnt really been substantiated from an observational perspective. So hes using various software programs to compare the models predictions with observed properties.

Dr. Opher is a huge name in the field of heliophysics, Hubbert says of his interest in coming to BU. The resourceshuman and equipmenthere are great, and I know that whatever I put my hands on has the potential to be a new and innovative discovery.

He says that another benefit of the REU program is its mentoring style, which makes the students in the program feel like their work is important and appreciated. This, unfortunately, is not something that every program puts focus on when bringing in summer interns. Working at NASAs Goddard Space Center last summer, he says, the sheer magnitude of the operation made it very easy . . . to get lost in the fray. Here, I knew that the environment would be more intimate.

In addition to their individual research, the students gather Wednesdays for discussions, either about specific topics in astronomy or graduate study and career opportunities in the discipline, says Marc Kornbleuth (CAS13,16, GRS20), a research fellow with Opher who runs the weekly discussions.

REU is a great exposure for the [astronomy] department, says Opher. These students come out from here; theyll tell their advisers [at their universities] how great a program it was. As an example, Kornbleuth cites one REU participant from two years ago who is returning to campus this fall for graduate study.

The good news for students thinking of applying to the program is that you dont necessarily have to be an astronomy or physics prodigy to participate. Opher recalls one student she unsuccessfully tried to recruit who had a really strong background in arts but was interested in exploring astronomy. And I thought this would be a very interesting combination.

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NSF Program Brings Budding Astronomers to BU - BU Today

What is the attraction of a total eclipse, deep space?

What is so special about seeing a total eclipse that you're willing to take time off from work to travel hundreds of miles and spend hundreds of dollars to see something that lasts two minutes?

Jeff Struve, president of the Quad-Cities Astronomical Society, opened his laptop computer. "This will showyou why we're going," he said.

He clicked a few keys and up popped an image of the sun, totally blocked by the moon, with only its corona, the outermost part of the sun's atmosphere, glowing like around diamond ring in the darkness of space.

"It's beautiful," he said.

And if you don't grasp that,thenwords won't explain it.

***

Paul Levesque, from Moline, grew up in New England, withthe 1972 hit song "You're So Vain" by Carly Simon playing in his head. The tune was aboutan unnamed, self-absorbed lover who, among other things,"flew (his)Learjet up to Nova Scotia to see the total eclipse of the sun."

The haunting words and melody referencing an eclipse in 1970 planted an interest for Levesque that grew through the years.

About a year ago, he realized he would be near atotal eclipse said, "Holy cow! I've got to see it! It's a bucket list thing. I cannot miss this."

He is traveling to Missouri for his brush with totality, although he's not saying exactly where. "I'm psyched about it," he said.

"It's like a spiritual thing. It touches you. I mean, the sun goes dark in the middle of the day! What the heck? How is that even possible?"

***

Robert Mitchell, physics professor at St. Ambrose University, got hooked onastronomy when he found two books one on constellations and one on planets in his elementary school library.

"It just clicked with me," he said.

Although he's all about science, he finds it "the most incredible coincidence that the distance of our moon and the distance of our sun are just right so that their apparent sizes are almost exactly the same (from Earth) even though the sun is 400 times as big as the moon and is 400 times as far away."

It is those relative distances and sizes thatmake the eclipse possible.

"It's coincidental. Or is it?" he said.

In addition to teaching, Mitchell isdirector of the university-owned Menke Observatory at theWapsi River Environmental Education Center near Dixon.

*********

What is it about deep space that attracts you?

Mike Ombrello, of East Moline, came to his interest in space through photography. One of his nighttime photos happened to capture the Milky Way, the galaxy that includes Earth, "and the next thing you know, I bought a telescope," he said.

"Since then, I've been photographing deep space objects."

Looking through atelescope, you can see things that seem like make-believe because you have never seen anything like them before. You see greatgalaxies with literally billonsand billions of stars and greatnebula, or gas dust, flaring forth.

You can hardly believe these things exist because whenyou look at the sky with your naked eye, you can't see them. So you wonder if the telescope is playing tricks. But no, those things arereal. They exist. And Ombrello takes pictures of them.

He says his equipment isn't especially expensive, but he's able to capture nebula,the nearby galaxy called Andromeda, that appears as a big whirlpool, and many other objects.

This has led to more exploration and learning.

"I never knew where the Milky Way was or how to find it," he said.

Now astronomy and peering into space is something of an addiction.

"I can't wait for it to get dark enough to see something else," he said.

****

Alan Sheidler, president of the Popular Astronomy Club, grew up on a farm in Ohio in the 1960s. There wasn't much light pollution so he could see lots of interesting things in the night sky and,with the Kennedy Administration space program in full gear, "science was king."

Those two elements combined to spur his interest, and he received an inexpensive telescope as a present from his parents for better viewing.

Then one sunny day when he was in late grade school, he and his brother were playing in the barn when they noticed something unusual. They noticedthe sun pouring through a knothole in the barn siding at just the right angle that it cast an image on the opposite wall.

"We could see a circle of light on the other side of the barn," Sheidler recalled. "We looked at it in closer detail and realized we had a perfect image of the sun. The knothole was like a pinhole viewer.

"We got a piece of paper and held it up and we could see sunspots on the sun. We tracked this over a series of weeks, and we could see the spots move. We had a solar observatory in the barn with knotholes."

Eventually the brothers weren't satisfied with the knotholes that existed, so they got a hand drill and made new ones, allowing them to have viewings at different times of the day or year.

They didn't tell their dad until years later. He just smiled, Sheidler said.

Sheidlerretired from Deere & Co. in product development about a year ago, so he's had more time to pick back up on astronomy. He's traveling to Missourito see the eclipse.

He also has made trips to areas of "dark sky," such as Arizona, the Big Island in Hawaii and the outback of Australia.

"That is the most amazing sky I've ever seen because there is zero light," he saidof Australia. "You'd swear there are clouds in the sky. But it's the Milky Way.

"We have no idea what we're missing here," he said.

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The Great American Eclipse: Q-C astronomy clubs, others get ready ... - Quad City Times

Mankind has long gazed toward the heavens, searching to put meaning and order to the universe around him. Although the movement of constellations patterns imprinted on the night sky were the easiest to track, other celestial events such as eclipses and the motion of planets were also charted and predicted.

Definition of astronomy: Astronomy is the study of the sun, moon, stars, planets, comets, gas, galaxies, gas, dust and other non-Earthly bodies and phenomena. In curriculum for K-4 students, NASA defines astronomy as simple the study of stars, planets and space. Astronomy and astrology were historically associated, but astrology is not a science and is no longer recognized as having anything to do with astronomy. Below we discuss the history of astronomy and related fields of study, including cosmology.

NGC 7026, a planetary nebula, lies just beyond the tip of the tail of the constellation of Cygnus (The Swan).

Historically, astronomy has focused on observations of heavenly bodies. It is a close cousin to astrophysics. Succinctly put, astrophysics involves the study of the physics of astronomy and concentrates on the behavior, properties, and motion of objects out there. However, modern astronomy includes many elements of the motions and characteristics of these bodies, and the two terms are often used interchangeably today.

Modern astronomers tend to fall into two fields: the theoretical and the observational.

Observational astronomers in the observational field focus on direct study of stars, planets, galaxies, and so forth.

Theoretical astronomers model and analyze how systems may have evolved.

Unlike most other fields of science, astronomers are unable to observe a system entirely from birth to death; the life of worlds, stars, and galaxies span millions to billions of years. As such, astronomers must rely on snapshots of bodies in various stages of evolution to determine how they formed, evolved, and died. Thus, theoretical and observational astronomy tend to blend together, as theoretical scientists use the information actually collected to create simulations, while the observations serve to confirm the models or to indicate the need for tweaking them.

Astronomy is broken down into a number of subfields, allowing scientists to specialize in particular objects and phenomena.

Red spots on Jupiter, photographed on Feb. 27, 2006.

Planetary astronomers, for instance, focus on the growth, evolution, and death of planets, while solar astronomers spend their time analyzing a single starour sun. Stellar astronomers turn their eyes to the stars, including the black holes, nebulae, white dwarfs, and supernova that survive stellar deaths.

Galactic astronomers study our galaxy, the Milky Way, while extragalactic astronomers peer outside of it to determine how these collections of stars form, change, and die.

Cosmologists focus on the universe in its entirety, from its violent birth in the Big Bang to its present evolution, all the way to its eventual death. Astronomy is often (not always) about very concrete, observable things, whereas cosmology typically involves large-scale properties of the universe and esoteric, invisible and sometimes purely theoretical things like string theory, dark matter and dark energy, and the notion of multiple universes.

Astronomical observers rely on different wavelengths of the electromagnetic spectrum (from radio waves to visible light and on up to X-rays and gamma rays) to study the wide span of objects in the universe. The first telescopes focused on simple optical studies of what could be seen with the naked eye, and many telescopes continue that today. [Celestial Photos: Hubble Space Telescope's Latest Cosmic Views]

But as light waves become more or less energetic, they move faster or slower. Different telescopes are necessary to study the various wavelengths. More energetic radiation, with shorter wavelenghts, appears in the form of ultraviolet, x-ray, and gamma-ray wavelengths, while less energetic objects emit longer-wavelength infrared and radio waves.

This large field-of-view image of sunspots in Active Region 10030 was observed on July 15, 2002. Researchers colored the image yellow for aesthetic reasons.

Astrometry, the most ancient branch of astronomy, is the measure of the sun, moon, and planets. The precise calculations of these motions allows astronomers in other fields to model the birth and evolution of planets and stars, and to predict events such as eclipses, meteor showers, and the appearance of comets.

Early astronomers noticed patterns in the sky and attempted to organize them in order to track and predict their motion. Known as constellations, these patterns helped people of the past to measure the seasons. The movement of the stars and other heavenly bodies was tracked around the world, but was prevalent in China, Egypt, Greece, Mesopotamia, Central America, and India.

The image of an astronomer is a lone soul at a telescope during all hours of the night. In reality, most hard-core astronomy today is done with observations made at remote telescopes on the ground or in space that are controlled by computers, with astronomers studying computer-generated data and images.

Since the advent of photography, and particularly digital photography, astronomers have provided amazing pictures of space that not only inform science but enthrall the public. [All-Time Great Galaxy Photos]

Astronomers and spaceflight programs also contribute to the study of our own planet, when missions primed at looking outward (or travelling to the moon and beyond) look back and snap great pictures of Earth from space.

Nola Taylor Redd

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What is Astronomy? Definition & History - Space.com

In 2015, reports of an unusual signal observed around a distant star spurred suggestions of the presence of an alien megastructure. But new research suggests that the bizarre discovery could instead be the sign of a destroyed world.

While most planets orbit their stars from a safe distance, some see their suns up close and personal. Orbiting far closer than Mercury, these worlds experience extreme temperatures that cause their atmospheres to expand. If the planet is too small, with too little gravity to hold on to the growing atmosphere, it can wind up losing it. A handful of worlds have been spotted with the remnants of their atmospheres trailing along behind them.

Disintegrating planets can reveal extremely important compositional information, which is the primary reason we are interested in them, Jake Hanson, a doctoral student at Arizona State University, told Astronomy by email. Hanson, who is studying how exoplanets lose their atmospheres, presented his research in April at the Astrobiology Science Conference in Mesa, Arizona.

A look inside When scientists see an atmosphere flowing behind its planet, its unlikely to be the one the world was born with. That atmosphere was likely lost soon after the planet began its close residence to its star. Instead, Hanson said the molten surface of a disintegrating planet most likely resupplied the atmosphere, as gases escaped from the overheated landscape.

Depending how much of the planet has already evaporated, we could be looking deep into the remnants of a giant planet or near the original surface of a rocky planet or near the core of a rocky planet, for that matter, he said.

Even the best instruments can only peer at the upper layers of the atmosphere surrounding a world beyond the solar system. But these melting worlds may provide the first look at whats going on deeper down, at the surface.

To help understand whats happening on these worlds, Hanson first modeled how an exoplanet might look if it was steadily losing its atmosphere at a consistent rate. He found that it was difficult to drain an atmosphere from a planet by the same degree over time. Its more likely that atmospheres on these worlds build up in large quantities, then suddenly blow off in massive chunks.

The rock is vaporized into an atmosphere and then, BAM! Bulk ejection, Hanson said in his presentation. Then reboot and restart.

The unusual signal could provide a way to detect worlds too small to be spotted with current instruments, he said. The four disintegrating worlds known to date are small, estimated to have diameters within the size of Earth and the Moon, while their massive comet-like tails suggest they are losing roughly an Earth-mass of atmosphere every billion years.

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"Alien megastructure" star may be a sign of a dying world - Astronomy Magazine

Artists illustration of the LISA Pathfinder spacecraft. Credit: ESA

The European Space Agencys LISA Pathfinder spacecraft, now sailing around the sun on a trajectory away from Earth, was deactivated Tuesday after a nearly 18-month mission testing previously-untried lasers, vacuum enclosures, exotic gold-platinum cubes and micro-thrusters needed for a trio of gravitational wave observatories set for launch in the 2030s.

Stefano Vitale, principal investigator of the LISA Pathfinder missions core instruments, sent the long-planned command to passivate the probe at 1800 GMT (2 p.m. EDT) Tuesday from the European Space Operations Centre in Darmstadt, Germany.

The end of LISA Pathfinders mission Tuesday marked another turning point in gravitational wave research, a field of astrophysics reinvigorated in the last two years by two major advances, according to Paul McNamara, the missions project scientist at ESA.

First came the launch of LISA Pathfinder on Dec. 3, 2015. Three months later, scientists announced the first confirmed detection of gravitational waves, ripples in the fabric of spacetime produced by the movement of massive objects in space, such as immense supermassive black holes at the centers of galaxies.

The gravitational waves, first predicted more than a century ago by Albert Einstein, were discovered by scientists crunching data gathered in September 2015 from a ground-based observatory called LIGO, which has antennas positioned 1,800 miles (3,000 kilometres) apart in Hanford, Washington, and Livingston, Louisiana.

Gravitational wave research requires huge detectors spread of thousands or millions of miles because the ripples are observed at very low frequencies as they travel through the Universe at the speed of light. Astronomers say the waves, which can be triggered by violent phenomena such as black hole mergers, reveal a new way of studying the cosmos impossible with conventional optical telescopes.

The back-to-back breakthroughs catapulted gravitational waves to the forefront of astronomical journals and space mission planning.

Was it a big step forward? Absolutely, because up to this point there were two doubts, McNamara said in an interview this week with Spaceflight Now. One doubt was gravitational waves dont exist, and then LIGO comes along and detects them.

Then we launched LISA Pathfinder, and we demonstrated the hardware in space, he said. So the two big questions do they exist and can we detect them? both were answered within three months of each other.

LISA Pathfinder was named for a follow-on mission dubbed the Laser Interferometer Space Antenna, which was formally selected by ESAs science planning board June 20 to move into the next phase of mission planning after decades of starts and stops.

With the astonishing success of LISA Pathfinder, we now know how to build a mission like LISA, said Vitale, a researcher at the University of Trento and the National Institute for Nuclear Physics in Italy.

Launched from French Guiana aboard a Vega rocket, the hexagonal space probe is about the size of a small car. LISA Pathfinder reached an operating point at the L1 Lagrange point nearly a million miles (1.5 million kilometres) from Earth in January 2016, lurking near a gravitational balance point between in a direction toward the Sun.

In March 2016, on the first day LISA Pathfinder was in full science mode, ground controllers confirmed the mission had already met its minimum success requirements.

Two gold-platinum test cubes launched inside the LISA Pathfinder spacecraft were released from their launch restraints, a complicated procedure involving needle-like appendages that carefully pulled away from the cubes each 1.8 inches (46 millimetres) on a side and with a mass of 4.4 pounds (2 kilogrammes) to avoid disturbing them with electrostatic forces.

The crux of the mission was to prove the test cubes could be kept in a constant state of nearly perfect free fall during LISA Pathfinders mission.

Two sets of low-impulse thrusters essentially steered the spacecraft around the free-floating test masses suspended inside two vacuum enclosures placed 15 inches (38 centimetres) apart on the satellite.

Accelerometers aboard LISA Pathfinder precisely tracked its movements, and a control computer sent signals to the low-thrust rocket packs outside the probe to continuously correct to keep the test cubes from contacting the walls of their chambers.

A high-precision laser interferometer constantly measured the range between the two test cubes, and that device also exceeded requirements, measuring the relative motion of the test masses with a precision of a femtometre, or one quadrillionth of a metre.

LISA Pathfinder is 10,000 times more stable than any satellite flown on a previous science mission, officials said, demonstrating that it was possible for the test masses to remain virtually motionless with respect to each other.

ESA said the test masses had a relative acceleration of only ten billionths of a billionth of Earths gravity, an achievement made possible by a tedious accounting of every component of the spacecraft that could influence the floating metallic cubes.

Many of the lessons learned from LISA Pathfinder were not in how to build a space-rated gravitational wave detector, but how to operate it, McNamara said. Even the switch-on of a transponder or star tracker added noise to the instrument beyond acceptable limits.

This is such a sensitive instrument that it responds to anything changing whatseover, NcNamara said. Weve learned that, for LISA, we have to assume if you make any changes on-board its going to take you time to recover back into equilibirium. If you turn any unit on, you turn any heater on, or do anything on the spacecraft to put it in a slightly different orientation, itll take you a week to get back to operational status.

Such precision is needed because gravitational waves have an amplitude of a few millionths of a millionth of a meter over a distance of a million kilometres (621,000 miles). Any larger movement of the test masses would mask the gravitational wave.

The LISA Pathfinder mission cost nearly 500 million, a figure that includes contributions from ESA, NASA and other institutions scattered across Europe.

LISA Pathfinder was conceived to prove a gravitational wave mission was technically feasible.

People just didnt think it was possible, McNamara said. Thats why LISA Pathfinder came into being. It was just to see could we build an instrument which was quiet enough.

The concept for the LISA mission selected by ESA last month calls for three spacecraft similar to LISA Pathfinder to launch in 2034 into an orbit around the sun that trails the Earth.

The LISA spacecraft will fly in a triangular formation more than 1.5 million miles (2.5 million kilometres) apart, linked by lasers to track the exact distances between the nodes, which will each contain two free-floating test masses. Sensors will watch for tiny variations in the range between the craft as gravitational waves pass through the solar system.

With gravitational waves, its a completely new endeavour were taking on, McNamara told Spaceflight Now. This idea of flying three spacecraft separated by millions of kilometres, and you have to be able to measure the distance to a hundredth the size of an atom.

We have exceeded not only the requirements set for LISA Pathfinder, but also the accuracy required for LISA at all frequencies: we are definitely ready to take the next step, said Karsten Danzmann, a LISA Pathfinder co-investigator, the lead proposer of the LISA mission, and director at the Max Planck Institute for Gravitational Physics in Germany.

ESA expects the LISA mission to cost more than 900 million (more than a billion euros), not including support from NASA.

Paul Hertz, director of NASAs astrophysics division, said Wednesday that the U.S. space agency wants to contribute technology and hardware to the LISA mission roughly equivalent to around 20 percent of the missions total cost.

NASA and ESA originally planned a larger, more ambitious LISA mission, but NASA dropped out of the partnership in 2011 due to budget constraints. ESA pressed on with a scaled-back gravitational wave observatory, which received prioritisation from the agency in 2013 ahead of the LISA concepts selection last month.

European officials want ESA to lead the LISA mission to avoid falling victim to another failed partnership, but NASA will still be a significant contributor. After discussions in the last few years for NASA to be a 10 percent partner, the U.S. stake in the LISA mission is now likely to be closer to 20 percent.

We are talking about a more substantial contribution than a 10 percent share, Hertz said. ESA has welcomed us as a very major partner.

NASA might develop lasers and telescopes for the LISA observatory, or the missions charge management system. Another potential U.S. addition to the mission could be the micro-thrusters needed to deftly control each of the LISA spacecraft, which will be assembled in Europe.

LISA is third in ESAs Cosmic Vision line of large-class billion-euro space science missions.

A robotic spacecraft that will orbit Jupiter, and then circle Jupiters largest moon Ganymede, is on schedule for launch aboard an Ariane 5 rocket in 2022, followed by liftoff of the Athena X-ray astronomy observatory in 2028.

Then it will be LISAs turn.

Before shutting down LISA Pathfinder, controllers fired its thrusters to nudge it out of its post at the L1 Lagrange point in April to head into a heliocentric orbit around the sun. The maneuver minimized the chance the spacecraft will return to Earths vicinity.

LISA Pathfinders science mission officially ended June 30, and engineers spent the final weeks practicing procedures to recapture the test masses inside their housings, which might be necessary if problems develop on the LISA mission. Other final tasks included monitoring the instruments behaviour when the spacecrafts thrusters were turned off, and tracking the test masses response to a coronal mass ejection from the sun.

Scientists were eager to see how the spacecraft responded when it was zapped by ionizing energy from a solar eruption last week. In particular, mission officials wanted to know whether the instrument would still provide useful science data when the test masses were hit by charged particles. Reviews of that data are still ongoing, McNamara said.

The final commands uplinked to LISA Pathfinder turned off the crafts transponder and corrupted the memory files of the probes primary and redundant computers by filling the processors with the names of scientists and engineers who worked on the mission.

This is a celebration, and its certainly not a sad moment, Vitale said moments before sending the order that silenced the spacecraft.

LISA Pathfinder has done everything and more that we could have asked of it, McNamara said. And its allowed LISA to go ahead, so yes, were sad thats going away and its ending, but were very happy LISA is taking off.

Its another 17 years to go before that one launches, so well exercise our patience.

Email the author.

Follow Stephen Clark on Twitter: @StephenClark1.

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Pioneering probe for gravitational wave observatory ends mission - Astronomy Now Online

The Flint Hills Discovery Center, in collaboration with the department of physics at Kansas State University, hosted an astronomy viewing July 14. The event was free to the public and focused on educating attendees about the night sky.

The event allowed local residents to view the moon, planets and stars through 8-inch reflecting telescopes and 4-inch refracting telescopes. The major planets the attendees viewed included Jupiter and Saturn.

This is making science real, and people are actually able to experience it, Jonathan Mertz, event supervisor at Flint Hills Discovery Center, said. Its not something in a book; its not something in a big city. Its something here in Manhattan where people can come together and experience science and something really great thats going to be happening.

Stephen Bridenstine, curator of education at Flint Hills Discovery Center, said the event was inspired by the upcoming solar eclipse occurring Aug. 21.

I think one of the most important things it does is it gets people excited about science, Bridenstine said. Its a free program. Theres no cost to come and experience this tonight. Its a way that we can fulfill our mission of serving the Manhattan community and providing some great opportunities to experience the natural world around them, including the night sky.

The astronomy viewing was led by Chris Sorensen, distinguished professor of physics at K-State and local astronomy enthusiast.

What you hope is some of these kids will realize there are things they cant see normally, Sorensen said. If they take special effort, theres a lot of hidden secrets in the universe, and theyre pretty neat and beautiful.

The astronomy viewing provided a unique learning experience for those in attendance.

Were strong advocates for what we call informal education, Bridenstine said. That means grabbing a telescope and looking at the night skies, hiking through the prairie and looking at the rocks and the flowers. Its learning out in the world around you. Not all learning happens in the classroom.

Sorensen used his personal, handmade telescope for the event. He said he began building the telescope when he was about 12 years old but was forced to stop after being unable to grind some of the parts into shape. Sorensen said he resumed the project when he was about 14 or 15 years old, and the telescope took less than a year to finish after that.

It was a very difficult thing to do, Sorensen said. I had to read books on how to do it. I probably learned tenacity building that telescope, and thats done me well throughout my career.

The event was educational for people of all ages, especially newcomers to astronomical observation.

Its family-friendly. It brings out a lot of people who have never been here before, Bridenstine said.

Sorensen said he was pleased to see so many people in attendance.

Its heartening to see that, Sorensen said. You realize theres a lot of people who want to broaden themselves up in all kinds of ways. Its good to seewe have a viable community.

The event demonstrated the effectiveness of local educational outreach, especially for younger audiences.

You know whats great about this event? Anyone can be a scientist, Bridenstine said. I think Chris Sorensen is a great example of why and how at a young age you can become interested in something, and you can make it your career or you can keep it a hobby.

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Upcoming solar eclipse inspires astronomy viewing night - Kansas State Collegian

Today, some bittersweet spacecraft news: The LISA Pathfinder mission is shutting down. Thats always a bit sad, but in this case, in sum, its actually good news: Thats because it accomplished all its goals. And even better, it means that a bigger, beefier mission will take its place! That mission, called LISA, was recently approved by the European Space Agency to continue its planning phase, aiming for a launch in 2034.

Why am I happy about this? Because LISA is the Laser Interferometer Space Antenna, and it will use what is essentially Star Trek technology to detect merging black holes all across the Universe.

So,yeah. How awesome is that? And, for a while, I feared it would never get off the ground. It hasnt yet, but the odds are looking much better now.

OK, you probably want a modicum of background here. Ill be glad to help.

Maybe youve read reports about LIGO, the Laser Interferometer Gravitational-Wave Observatory, which recently detected black holes merging for the third time. I wrote about that eventand gave a lot of background a couple of years ago when LIGO bagged its first black hole coalescence.

In a nutshell, one of the predictions of Einsteins Theory of Relativity is that when matter is accelerated it creates ripples in the fabric of spacetime, much as shaking a bedsheet up and down causes ripples in the fabric. These ripples are stronger if the objects are very massive, very dense and accelerated very rapidly.

You dont get more massive, more dense and more accelerated things in this Universe than two black holes at the very moment they eat each other.

There are a few ways this can happen. Probably the most common is from black holes that form when massive stars explode. If those stars are orbiting each other in a binary system, then, eventually, after both stars blow up, you get two black holes orbiting each other. As they emit gravitational waves those Einsteinian spacetime ripples they spiral in toward one another. Over a long time (usually billions of years), as the distance between them closes, they orbit faster and faster. Then, finally, accelerating each other to very nearly the speed of light, they merge into a single bigger black hole, emitting a fierce, sharp blast of gravitational waves.

These ripples in spacetime then move across the Universe at the speed of light. When they wash over our planet, they physically compress and expand space itself. The effect is incredibly tiny by the time these waves reach us: A typical ruler would only shrink or expand by a tiny fraction of the size of a proton! But these effects can be measured because we are very clever apes, we humans.

LIGO was built to find these ripples, and after decades of trying, it works! It can now feel the Universe shake as black holes collide.

But LIGO, as amazing as it is, isnt nearly as sensitive as whats possible. Enter LISA.

LISA is similar to LIGO, but itll be in space. There are lots of advantages to this. For example, LIGO is so sensitive it has to worry about individual oxygen atoms hitting its mirrors, distorting the signal. In space theres no air, so thats an improvement.

Also, this stretching of spacetime is easier to measure if you have a longer baseline. If your detector is short it only stretches and contracts a little bit, but if its 10 times longer the effect is 10 times bigger. LIGO has mirrors spaced a few kilometers apart, making it highly sensitive. Because LISA is in space, its detectors can be much farther apart. In fact, the plan right now is for the components to be separated by about 2.5 million kilometers!

If you want to think of it as sound (which it isnt, but the analogy isnt bad), LIGO can hear the loudest black hole mergers. LISA will hear the whispers. In fact, it should also be able to detect mergers between neutron stars and even white dwarfs, which are far quieter than their denser black hole brethren.

So, how does it work? LISA is actually three disc-shaped spacecraft, launched together on one rocket. They each have an onboard propulsion system that will move them to their final separation of several million kilometers, forming an equilateral triangle in roughly the same orbit as Earth, but 20 or so million kilometers away from us.

Like LIGO, LISA will use lasers. Each spacecraft will have onboard two lasers, each of which will fire at one of the other two spacecraft. Using a technique called interferometry, the distances between the spacecraft can be measured with utter precision:

But theres a problem with this. The spacecraft need to be able to measure their relative positions with incredible accuracy, so that the teeny tiny effects of a passing gravitational wave can be measured. But there are lots of forces in space that would totally wash that out. Tides from the Earth, Moon, and Sun, cosmic rays, solar wind and more would all be far stronger, moving the spacecraft around and ruining the measurements.

To overcome this, inside each laser assembly is a small, exquisitely crafted cube made of gold and platinum (yes, seriously; theyre very stable and that makes them useful). Each cube, called a test mass, is about 4.5 or so centimeters on a side and has a mass of about 2 kilograms. They are totally disconnected from the LISA spacecraft, untouched by it in any way, allowed to float completely freely. The tolerance is extreme: No force on the cube is allowed more than about that exerted by the weight of a bacterium.

See what I mean by Star Trek technology?

In this way, the cubes are freely floating in orbits around the Sun, and the spacecraft keep position around them. Using extremely sensitive sensors, each spacecraft keeps itself precisely aligned with the cube inside it, measuring their exact location at all times.

The cubes act as benchmarks for the spacecraft around them. As long as the cubes are allowed to move freely, then a gravitational wave passing through them would change their relative separation, allowing it to be detected. The spacecraft act like shields, preventing outside forces from affecting them really, these forces affect the spacecraft, which then use incredibly low-thrust engines to maintain their strictly controlled positions. If theres a force on the spacecraft, say the solar wind, then the thrusters counteract that to make sure the spacecraft stays perfectly centered around the cubes. And I do mean weak: It would take a thousand of these thrusters to generate the same weight as a piece of paper in your hand!

I like to think of all this using an odd analogy: curling. Thats a sport played on an ice lane where a player throws a heavy mass (called a stone) and tries to place it in a target area downrange. Other players, called sweepers, have brooms and they rapidly sweep the ice ahead of the stone, decreasing the friction and making sure the stones trajectory is true.

For LISA, the test masses are the stone, and the sweepers are the spacecraft. They never touch the stone, but they make sure its path is true.

Now, if a gravitational wave passes through the LISA spacecraft, the pattern of light created by the laser changes, and this can be measured with ridiculous accuracy. Even though they will be separated from each other by a distance several times greater than the distance of the Moon from Earth, they will measure their relative positions to an accuracy of a few trillionths of a meter. Yes, trillionths. For those who love words as much as I do, a trillionth of a meter is a picometer. Feel free to work that into your next conversation.

And, again, this exemplifies the idea of how astonishingly advanced this tech is.

This brings us back to LISA Pathfinder. We know all this technology needed for LISA will work because the European Space Agency successfully tested it using Pathfinder. It launched in late 2015 and was equipped with lasers, cubes and other bits of tech LISA will utilize to measure the whisper from colliding hyperdense cosmic objects. It was amazingly successful and completed its mission on June 30. Today it will be shut down, having paved the way for LISA to continue.

Im glad this is happening. Many years ago, NASA was partnered with the European Space Agency to help build LISA. I actually worked a bit on the Education and Public Outreach for the mission, writing up descriptions of how it worked and what it would do. But shortsighted budgetary decisions meant NASA had to pull out of the development, which upset me greatly at the time.

However, over time and with a lot of cajoling by scientists, the U.S. has rejoined the mission as a senior partner, with the ESA leading the way. Im very glad to see this. Now that LIGO has shown we can detect gravitational waves, and LISA Pathfinder has shown the advanced technology is possible, LISA itself will open the floodgates of data. It took a huge effort for LIGO to allow us to dip our toes in the water. Hopefully LISA will let us dive in.

My thanks to NASALISAStudy Scientist Dr. Ira Thorpe for talking to me about how the spacecraft measure their distances and clearing up a misconception I had about the test masses!

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LISA will fly and listen for black holes eating each other - SYFY WIRE (blog)

the Irish News

Science up your Instagram feed with this new astronomy account the Irish News An ESO spokesman said: We invite you to follow ESO to revel in spectacular vistas of the universe, taken with some of the most powerful telescopes in the world, to learn about the astounding discoveries that astronomers make, and to view life at ESO's ... and more »

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Science up your Instagram feed with this new astronomy account - the Irish News

The Pale Red Dot team is coasting off the success of their discovery last year of a planet in the Proxima Centauri system system by casting its net even wider as the Red Dots campaign.

Whereas Pale Red Dot focused just on Proxima Centauri, Red Dots is looking toward Barnards Star and Ross 154 as well. These three stars will be held up to intense scrutiny by the team in the hunt for planets or in the case of Proxima, additional planets.

Barnards Star has been a popular target since the 1963 announcement by Swarthmore College professor Peter van de Kamp of a Jupiter-mass planet around it. His observations ended up discredited, as the telescope he used at Sproul Observatory had a flaw that caused some stars to appear to wobble when they were doing no such thing.

We are inviting anyone willing to collaborate to observe the stars' brightnesses and to join our campaign, Mikko Tuomi, a European Southern Observatory astronomer and Red Dots scientist, said in an email. We have already 1,700 brightness observations of Ross 154 from 5 different observers and as many as 2,500 brightness observations of Barnard's star from as many as 9 observers (Barnard's star is on the northern sky, so more accessible for US and European observers) using as many independent telescopes helping us in studying the variability of these stars in detail.

And one of the observatories participating isnt an optical telescope at all. Its the radio telescope at the Arecibo Observatory in Puerto Rico.

Planets can be detected in the radio spectrum because they disturb known radio emissions of the star (e.g., pulsars) or emit their own radio emissions, Abel Mendez, director of the Planetary Habitability Laboratory at Arecibo, says.

Mendez says that no planets have been found by radio telescopes beyond a handful of pulsar planets, but the team is hopeful.

Big short-periods planets in elliptical orbits around red dwarf stars are probably easier to detect since they might produce more interactions with the star (e.g., tides) to alter their flare patterns or frequencies, he says.

The Red Dots team is logging its progress on its website. All three stars are less than 10 light-years away, so detecting planets around them could make our corner of the universe seem a little less lonely.

Excerpt from:

The hunt is on for planets around some of our closest neighboring stars - Astronomy Magazine

Thursday, July 20, 2017 2 p.m. to 3 p.m.

Location: Emera Astronomy Center, 167 Rangeley Road, Orono, Maine

For more information: 207-581-1341; astro.umaine.edu

ORONO Back to the Moon for Good will be shown 2-3 p.m. Thursday, July 20, Emera Astronomy Center, 167 Rangeley Road.

Immerse yourself in a race to return to the Moon 40 years after the historic Apollo landings. See how a competition among privately funded international teams is ushering in a new era of lunar exploration, and the new opportunities for exploration of our nearest neighbor in space. Learn about the Moons resources and discover what humanitys future on the Moon might hold. Narrated by Tim Allen.

The program includes a look at the night sky as viewed from Maine.

FMI: (207) 581-1341 or http://www.astro.umaine.edu

This post was contributed by a community member. Submit your news

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'Back to the Moon for Good' at Emera Astronomy Center - Bangor Daily News

This artists conception shows how families of asteroids are created. Credit: NASA/JPL-Caltech

Scientists have long held the belief that planets including Earth were built from rocky asteroids, but new research challenges that view.

Published in Science Advances, a journal of the American Association for the Advancement of Science, the research suggests that many of the original planetary building blocks in our solar system may actually have started life, not as rocky asteroids, but as gigantic balls of warm mud.

Phil Bland, Curtin University planetary scientist, undertook the research to try and get a better insight into how smaller planets, the precursors to the larger terrestrial planets we know today, may have come about.

Planetary Science Institute Senior Scientist Bryan Travis is a co-author on the paper Giant Convecting Mud Balls of the Early Solar System that appears in Science Advances.

The assumption has been that hydrothermal alteration was occurring in certain classes of rocky asteroids with material properties similar to meteorites, Travis said. However, these bodies would have accreted as a high-porosity aggregate of igneous clasts and fine-grained primordial dust, with ice filling much of the pore space. Mud would have formed when the ice melted from heat released from decay of radioactive isotopes, and the resulting water mixed with fine-grained dust.

Travis used his Mars and Asteroids Global Hydrology Numerical Model (MAGHNUM) to carry out computer simulations, adapting MAGHNUM to be able to simulate movement of a distribution of rock grain sizes and flow of mud in carbonaceous chondrite asteroids.

The results showed that many of the first asteroids, those that delivered water and organic material to the terrestrial planets, may have started out as giant convecting mud balls and not as consolidated rock.

The findings could provide a new scientific approach for further research into the evolution of water and organic material in our solar system, and generate new approaches to how and where we continue our search for other habitable planets.

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Planets like Earth may have had muddy origins - Astronomy Now Online

An astronomy park honoring astronaut John Glenn will open in the late fall at Hocking Hills.

Construction was recently started on the John Glenn Astronomy Park about 40 miles southeast of Columbus in secluded, tranquil woods. Hocking Hills is known for its lack of light pollution, making it a favorite viewing spot for astronomy fanatics.

The Friends of Hocking Hills State Park is privileged to help honor John Glenns legacy by developing a facility that has such tremendous potential to offer visitors from around the globe an unforgettable experience. said Julieann Burroughs, president of the Friends of Hocking Hills State Park board of directors. The park will spark an interest in science, exploration and astronomy among visitors of all ages and is expected to become a meaningful scientific research facility.

The park, designed by Ohio-based M&A Architects, will include an 80-foot Solar Plaza that is encircled by a law wall with notches that offer framed views of the sun on certain days. An enclosed 540-square-foot observatory also features a retractable roof to permit night sky viewing. The park will also feature gathering areas, open green space and parking.

Before John Glenn died in December, he agreed to lend his name to the park. Raymore added that increased tourism benefits the area through much-needed economic development, as visitors generate more than $134 million annually in the region.

Whats next for Austin Landing? Developer envisions expansion

In addition to miles and miles of trails through dense forests, stunning rock formations and rushing waterfalls, our star-filled skies get high marks from visitors, said Karen Raymore, Hocking Hills Tourism Association executive director. The Tourism Association is thrilled at the opportunity to offer one more reason for travelers to visit the region and a new way for them to experience another natural attraction, which has been here since the dawn of time.

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John Glenn Astronomy Park to open in Hocking Hills - Dayton Daily News

Our Milky Way galaxy is a collection of gas, dust, dark matter, and a couple of hundred billion stars. Most of those stars orbit the galactic center in a pinwheel-shaped disk about 100,000 light years across and a few thousand light years thick, but theres also a vast roughly spherical halo of stars around the galaxy stretching out about 100,000 light years, itself.

Most of the stars in the halo are moving around the Milky Way in nice, normal orbits. However, over time a handful have been discovered that are weird: Theyre moving too fast.

These stellar bullets are screaming around space much faster than the stars around them. Sometimes their velocity is so high that the galaxys gravity cant hold on to them: Their destiny is to escape the galaxy forever.

We call these high-velocity stars. A really big question is actually a pretty a simple one: Where did they come from? There are lots of possible origins for these stars (which Ill get to in a sec), but a new one has just been found, and Ill be honest, it surprised me: They are coming from the Large Magellanic Cloud (or LMC), a satellite galaxy of the Milky Way.

That startled me for a lot of reasons, but the biggest is that the LMC is over 150,000 light-years from us, and thats a long way to travel for a star even at high speed. But a paper just published outlines how it works, and its pretty convincing.

The main piece of evidence is that a lot of these high-velocity stars are seen in the constellations of Leo and Sextans. Thats significant, because if you map out the location and orbit of the LMC around the Milky Way, the LMC is headed in that direction (think of it as watching a car zoom past you on a road, and you can see its headed toward the east; it might be in front of you at this exact second, but you can extrapolate where it will be in a few minutes). It orbits our galaxy at about 380 kilometers per second, which is really fast, and if you could eject stars from it they would preferentially be found moving in the direction of the LMC itself.

Thats pretty good circumstantial evidence but, to be honest, its not enough. Can stars like this, in fact, be ejected from the LMC?

There are many ways to get stars blowing through space at high speeds. One is if the star starts out in life as part of a binary star, two stars orbiting one another. If they pass really near a black hole, one star can get swallowed by it while the other gets ejected at a pretty substantial clip. We think this happens in our Milky Way when a binary encounters the gigantic black hole at the galaxys exact center. Some high-velocity stars seen are consistent with this, but that doesnt explain the excess seen toward Sextans and Leo. Plus, theres no evidence the LMC has a big black hole like ours, so that doesnt really cover the observations.

There are other ways (for example, encounters with other stars in a dense stellar cluster can kick stars pretty hard), but its hard to account for both the number and distribution of these stars seen.

One way seems to fit the bill, though. You start with a binary system, where at least one of the stars is high-mass, more than 8 times the mass of the Sun. Eventually, that star will turn into a red giant, swelling hugely in size. The other star can then draw material off the giant, increasing its own mass. If they are close enough together, they can actually become whats called a contact binary, a peanut-shaped object which is essentially two stars sharing the same atmosphere! When this happens, the two stars actually can spiral in, getting very close together. As that happens, their orbital speed around each other increases.

Then, catastrophe: The more massive star explodes in a spectacular supernova! If it loses enough mass in the explosion, it no longer has enough gravity to hold the binary together, and the companion star gets flung away at high speed. A-ha! A high-velocity star.

This seems a little unlikely, though. How often does this happen?

Turns out, a lot! The scientists doing the study decided to find out just how common an occurrence this is in the LMC, so they did two things: They used a physical model of how stars form and evolve in the LMC to see how many high-velocity stars you can get this way, and then used a second physical model of the LMC and Milky Way system to see if the gravity of the two galaxies changes the way the stars behave (for example, the gravity of the LMC may slow down the stars ... but the ones shot out ahead of the LMC in its orbit get the galaxys velocity added to them, as a ball thrown out a car window gets the cars speed added to its own).

Their model simulated nearly 2 billion years of time, and what they found was pretty cool: Over that time, more than 860,000 stars will have escaped the LMC, making up about 80% of the high-velocity stars seen in the Milky Ways halo! That shows that its extremely plausible that the stars actually seen come from our companion galaxy.

There were other interesting tidbits to come out of this as well. Because these stars were once part of a contact binary, they may have started off lower mass, but gained mass before getting flung out into the Universe. If they wound up with more than about 8 times the Suns mass, they, too, would explode over time. The model predicts that about half the stars ejected from the LMC exploded on their way here. These supernovae leave behind either a dense neutron star or a black hole, which means thousands of these objects tiny, but possessed of super-strong gravity are blazing past our galaxy even now.

Now, dont fret: Theyre too far away to hurt us in any realistic way, but I do hope some science fiction author hears about this and devises a fun story based on them.

Interestingly, a lot of high-velocity stars are high-mass blue stars (called B stars in the astronomical stellar classification system). That, too, is naturally explained by them once being in a contact binary, where they gained enough mass to fall into this category.

So, how do we prove this? High-velocity stars can be found in a number of ways. In general,its through their spectrum; when you break the light up from a star into thousands of narrowly sliced colors, you can learn a lot about them, including their speed. But thats a hard measurement to make on a large scale.

You can also take images of lots of stars in the sky, wait a few years, then do it again. Stars moving rapidly enough in space will move noticeably in such a survey (if the observations are accurate enough). And there is such a survey: Gaia, which is mapping a billion stars in the Milky Way. Over the course of its multi-year mission it may find quite a few of these runaway stars.

So, is this idea of cannonball stars from the Large Magellanic Cloud correct? Maybe. I do like it, and it explains a lot. The good news is its testable, making predictions about the numbers, locations and types of stars we should expect to see in the Gaia survey. Time will tell, and we wont have to wait too long, since the survey results needed for this will be released over the next few years.

Every time I think Ive heard everything about astronomy, something new comes along. Alien invader stars from another galaxy! Science is just so much fun.

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Stellar cannonballs may be invaders from another galaxy - SYFY WIRE (blog)