Stars and meteor streaks are seen behind a medieval tombstone in a Bosnian village late on Friday. Photograph: Amel Emric/PA

Whether youre a budding astronomer equipped with binoculars and a telescope, a loved-up couple looking for a romantic way to spend a summer night or a family on a camping-holiday desperate for something to occupy the kids, tonights the night to look up and count those shooting stars.

On Saturday night, the skies above Ireland are set to be filled with thousands of shooting stars as the annual Perseids meteor shower reaches its peak. While this years display of night sky fireworks may be slightly obscured by a particularly bright moon, star gazers can still expect to see dozens of stars streaking across our skies.

The Perseids meteors, shed by comet Swift-Tuttle, stage their show every August and are among the brightest of all shooting stars. This year, as many as two of the streaking flashes of light may be visible every minute, given a good location and clear skies.

Because the moonlight is up youre probably as good watching in your backyard in the suburbs as you are in the countryside, said David Moore, chairman of Astronomy Ireland, adding that the best time to watch for stars would be between midnight and 4am on Sunday.

This year the moon will drown out the faint stars so instead of seeing one or two shooting stars every minute, you might only see half of this. The moonlight can create a haze and reduce the number of shooting stars you see.

Asked if he was expecting clear skies for the night, Mr Moore said Irish astronomers tend to ignore the forecast given the unpredictable nature of our weather. In this case cloud cover is what is important and its very difficult to predict cloud cover, it can vary from kilometre to kilometre.

He added that while the meteor shower will peak on Saturday night, its shooting star display will continue until at least Monday night.

Astronomy Ireland is calling on members of the public to count how many stars they see in a 15 minute period and email stars@astronomy.ie with their name, location and the night they watched the sky. There arent enough professional astronomers here to record the starts so its down to the general public to count every 15 minutes, said Mr Moore.

The meteors, mostly no bigger than a grain of sand, burn up as they hit the atmosphere at 58 km per second to produce a shooting stream of light in the sky.

Seen from the Earth, the Perseids appear to originate from one place in the north-east known as the radiant which happens to be near the constellation Perseus.

Robin Scagell, vice president of the Society for Popular Astronomy, advises people not to look towards the radiant, but to direct your gaze in the opposite direction.

The Perseids can be very bright and often quite spectacular, said Mr Scagell. Some meteor showers are slow, but we are moving into the Perseid stream so they are coming at us quite swiftly. I think under good conditions you might see one or two a minute, probably more towards Sunday morning rather than Saturday.

The Perseids were the first meteor shower to be linked to a comet when astronomer Giovanni Schiaparelli spotted their association with Swift-Tuttle in 1862.

The comet orbits the sun every 135 years. As the Earth crosses its orbit, it ploughs through some of the debris left by the icy object on previous visits. None of the particles are big enough to avoid destruction and reach the ground.

Additional reporting from PA

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Perseids meteor shower: How and where to see tonight's shooting stars - Irish Times

Local science historian and Colorado Springs native Steve Ruskin on Sunday will be at the Penrose Library, 20 N. Cascade Ave., to discuss his new book, "America's First Great Eclipse." (Photo from Amazon.com)

While looking forward to the total solar eclipse on Aug. 21, take a look back.

Local science historian and Colorado Springs native Steve Ruskin on Sunday will be at the Penrose Library, 20 N. Cascade Ave., to discuss his new book, "America's First Great Eclipse." The account centers on the day in July 1878, when the moon momentarily covered the sun over the Rocky Mountains in an event that Ruskin argues "changed astronomy forever."

"I didn't think that much had happened in the history of science in Colorado," said Ruskin, who has previously authored a book on John Herschel's 1833 astronomical expedition in southern Africa. "I was happy to find out I was wrong."

"America's First Great Eclipse" tells of the phenomenon 139 years ago that made the Springs "overrun" with scientists and tourists from afar. Famed astronomer and physicist Samuel Langley was among those eager to witness the eclipse at a high elevation. His determination led him to the top of Pikes Peak.

In 1878, Colorado was 2 years old as a state, and the Springs was on its way to becoming the resort envisioned by Gen. William Jackson Palmer. Ruskin found that the buzz surrounding the total eclipse that year was not so different from that surrounding this upcoming one. A celestial show like this spanning coast to coast hasn't occurred in 99 years. While the Springs will experience a partial eclipse, many in town are planning to drive to Wyoming or Nebraska, among the states along the "path of totality" where minutes of complete darkness will descend on the afternoon.

Ruskin is scheduled to speak at 1:30 p.m. in the downtown library's Carnegie Room.

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Colorado Springs author relates account of eclipse that 'changed astronomy' - Colorado Springs Gazette

A full room listens to Jamie Tayar discuss the science behind the eclipse

On Aug. 21, the first total solar eclipse of the millennium will turn day into night across the heart of the United States, and interest in this astronomic event is peaking.

The Ohio State University Libraries and the Ohio State chapter of Sigma Xi, the scientific research honor society, hosted a presentation about the 2017 eclipse this week. More than 50 guests filled a large conference room (after swamping a smaller classroom) to listen to Department of Astronomygraduate student Jamie Tayar discuss the science behind the eclipse.

It was 1979 when the United States last witnesseda total eclipse, when the moon passes between the Earth and the sun and blocks out the light of the sun. Hotel rooms in cities along the path of totality, where the eclipse will be most complete, have been booked for months. Astronomy experts are making regular appearances on local and national news.

Tayar is not surprised.

The eclipse is very accessible this time. Its going across the entire country and everybody in the U.S. is going to see something, she said. And its not a small something; its the sun being partially blocked out.

The uniqueness of the event depends on three celestial bodies the Earth, moon and sun -- lining up just so. Scientists from Ohio State and across the country will be traveling to locations in the path of totality to observe the eclipse.

Eclipses are one of the oldest astronomical techniques. You sit around and wait for something to go in front of something else and you study it while its happening, Tayar said.

Sigma Xi member Brian Hajek and his wife, Edith, searched for rooms along the route of the eclipse but, failing to find any, they are headed out to sea.

Royal Caribbean repurposed one of their cruises at the last minute so we jumped at the opportunity, Hajek said. Normally the ship would head to the Caribbean, but it will now sit off the South Carolina coast in an attempt to let passengers observe the eclipse.

Both Hajeks came away from Tayars presentation more prepared for their trip and the eclipse. They also left armed with a pair of Ohio State-branded eclipse glasses. Eye safety is critical when staring at the sun.

Researchers have done studies about eye damage during the most recent partial eclipse. Thats not a study you want to be a part of, Tayar said.

Tayar expects to be in Nashville for the eclipse with a former classmate. She hopes the interest in the eclipse will serve as a gateway for people to learn more about astronomy.

Its a really accessible way to get people excited about science.

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Total eclipse in the hearts of astronomy fans at Ohio State - The Ohio State University News (press release)

In the coming months, two asteroids will make relatively close passes by the Earth. Called 3122 Florence and 2012 TC4, neither will hit us so dont panic! though TC4 will come pretty dang close.

Lets talk about TC4, first. It was discovered in 2012, and is small, about 20 meters across. It takes just over two years to orbit the Sun, going out as far as the orbit of Mars and back to just inside the Earths orbit. It will pass the Earth once again on October 12, 2017.

Until very recently, it wasnt clear just how close it would get to Earth at that time; the last observations were made back in 2012, and the farther into the future you try to project an asteroids orbit, the fuzzier that prediction gets. Ive likened it to being an outfielder in a baseball game: The longer you can keep your eyes on the ball, the better youll know just where it is. If you had to close your eyes a second after the batter hit it, youd only have a vague idea where the ball would be when it gets near you!

Even though we knew the orbit of TC4 well enough from the previous observations to rule out an impact, the news gets better: It was recovered (that is, seen again since the first set of observations) on July 27, 2017 using the Very Large Telescope in Chile. These new observations improved the orbital calculations a lot, and we now know itll most likely pass about 44,000 km above Earths surface! A close shave, to be sure, (about three times Earths diameter), but a miss, nonetheless.

In fact, this asteroid gets close enough that it makes a great test case for detecting incoming asteroids and determining their orbits. Astronomers from NASA are using TC4s approach as an exercise to test their systems, initially setting things up to recover it, track it, and characterize the asteroids orbit.

It wasnt expected to be visible again for a few weeks, but the VLT observations threw something of a monkey in the wrench of that. Im not surprised they were surprised by the early recovery; when VLT saw it, TC4 was incredibly faint. At magnitude 26.8 (!), the faintest star you can see with your naked eye is 200 million times brighter. But VLT has an 8-meter mirror, so it has quite an advantage in detecting ridiculously faint objects.

Still, theres much that can be done. Astronomers all over the world will track it and, most excitingly,it will be observed using the Goldstone radio antenna, which can ping it with radar and get good measurements of its size, rough shape, and rotation rate. Observations from 2012 clearly showed TC4 changing in brightness as it passed us, which indicates it is elongated and rotating about once every 12 minutes.

Itll be a challenging target for small telescopes; itll be faint (around magnitude 16) until a few hours before closest approach, and, even then, itll only brighten to about magnitude 13 (about 600 times fainter than the faintest star you can see naked eye). Itll also be screaming across the sky, at least as far as asteroids go, moving at several degrees per hour. Hopefully, as more observatories watch it, the orbit will get nailed down, and its position in the sky can be more accurately predicted.

By the way, since I know people will ask: A collision with TC4 would be bad, though not apocalyptic. Its roughly the same size as the rock that blew up over Chelyabinsk, Russia in 2013. I dont want to downplay this, nor do I want to exaggerate it: That one exploded with the force of about a half million tons of TNT, which is substantial (like a small nuclear weapon), but localized. It was fortunate that no one was killed in that event (though a thousand were injured by flying glass when the shock wave from the explosion shattered windows), but had circumstances been slightly different, there could have been fatalities. So, an impact like that is a concern.

And, in fact, thats one of the major reasons astronomers want to study TC4. If another asteroid like it does come in on an impact trajectory some day, then our best weapon is our scientific knowledge of it. Well that, and a rocket with a kinetic impactor on it.

The other rock that will pass us soon is 3122 Florence, which will sail past Earth on September 1, 2017 at a distance of about 7 million kilometers (more than 15 times the distance from the Earth to the Moon). Thats a much larger margin than for TC4, but this encounter is no less interesting. Why? Because Florence is big.

Florence is about 5 kilometers (3 miles) across, and is, in fact, one of the biggest near-Earth asteroids known. Technically, Florence is what we call a potentially hazardous asteroid, because not only does its orbit brings it very close to Earth, but its also large enough to do serious, global damage should it hit us.

However, to be very clear, at the present time, an impact isnt possible. Thats because of the way its orbit is tipped as it goes around the Sun: It doesnt physically cross Earths orbit; it just gets close to us. And 7 million kilometers is a long way; even though its a big rock, it wont get bright enough to see without optical aid. Itll be visible in binoculars from a dark site, but a small telescope is what youd really need to see it (JPL has software to calculate ephemerides coordinates on the sky over time if you have some observational experience and want to see it, yourself).

Having said that, orbits do change over time due to the gravitational influences of the planets and other forces, so its possible some time in the distant future it might hit us, but that day wont be for a long, long time. In fact, this encounter is the closest it will get for at least the next 160 years! There will be several close encounters between now and the year 2177, but all are at least slightly farther away than this one will be.

So, far from being scared about this, you should be excited. This is the closest a large asteroid will safely get to us for some time, so the potential for scientific observations is great. I havent heard a lot about whats planned, just yet, but hopefully well hear something soon, and also get some fun images of it once it passes us by.

Asteroids are scientifically fascinating; rubble thats suffered countless impacts from other rocks over the billions of years of history of our solar system. By studying them, we learn so much about how our cosmic neighborhood came to be, and how its changed since its formation. And while the threat from them at any one time is low, its still real. So, studying them is critical.

As is usually the case, science may very well save the world.

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Two space rocks will (safely!) buzz Earth this fall - SYFY WIRE (blog)

Few subjects captivate minds young and old quite like astronomy.

Short of boarding a space shuttle, a planetarium offers the best possible environment to satisfy one's celestial curiosity, and better still, earn credits to fulfill a science requirement at Indiana University Northwest.

On Saturdays while classes are in session, Adjunct Professor Gregg Williams' astronomy students file into the Merrillville Community Planetarium, where Williams also happens to be the director, and has been for the past 35 years.

The planetarium, housed inside Clifford Pierce Middle School in Merrillville, greets visitors with a model space shuttle suspended from the ceiling and murals of stars and planets adorning the walls. When exiting the 64-seat planetarium, visitors even exit into a mini gift shop.

Having created at least half of the 50-plus shows that the planetarium shows to the entire region's K-12 audiences, Williams seems an obvious choice for college-level instruction as well.

Williams teaches The Solar System (A100), Stars and Galaxies (A105), and just this past summer, he added Charting the Night Sky (A109), rounding out a full three semesters of consecutive courses.

The new course examines what Williams calls "naked-eye astronomy," or what astronomy was like for the Earth-bound before the advent of technology and telescopes.

Speaking of "naked-eye astronomy," Williams, his students, and anyone with a passing interest will have an opportunity to learn about astronomy when a total eclipse of the sun will be visible across the continental U.S. on August 21, coinciding with the first day of classes at IU Northwest.

Solar eclipses occur during the new moon, when the moon is directly between the Earth and sun, causing the disk of the moon to partially or totally cover the disk of the sun. In Gary, the eclipse begins at 11:54 a.m., achieves its maximum view at 1:20 p.m. and ends at 2:43 p.m.

Williams said that eclipses provide a chance for modern people to re-connect with their ancient ancestors' awe of the sky.

"Besides checking the weather, most people give only a passing glance to the sky," Williams said. "By contrast, ancient people felt a connection to the heavens since they depended on the sun and stars to tell time and mark their calendars. Many people who observe a total eclipse of the sun report experiencing a sense of awe bordering on the spiritual. This response is probably very similar to the emotions our ancient ancestors felt as they saw the sun, upon which our planet depends for light and heat, temporarily blotted from view."

This observation reflects the type of discussions students will experience in Williams' newest course, as well as the others, which he says are "perfect for non-science majors." They are not mathematical, as some might assume, but rather, descriptive.

"The last time I had any kind of astronomy was probably in middle school which was many moons ago," laughs Denise Maragos, a 48-year-old from Schererville who is majoring in history.

"Having the class at a planetarium is awesome," she said, "because the shows really drive home the concepts from the unit we are working on. I have learned a lot and it has reignited my curiosity of the universe."

Anthony Taylor, 58, of Merrillville admitted that science was never his strong suit, so when he learned that astronomy would satisfy his major's science requirement, he was happy to register.

"I've learned so much from the course and have a greater appreciation every time I look into the night sky," said Taylor, who is pursuing a bachelor's degree in general studies.

Erika Rose is a media communications specialist for Indiana University Northwest. Kevin Fryling of IU Communications contributed to this article.

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IU Northwest astronomy professor explains fascination with upcoming solar eclipse - Chicago Tribune

There are so many photographs of eclipses, and while theyre all amazing to see, this one might be the most special.

Emeritus J. McKim Kim Malville, professor of astrophysical and planetary sciences at the University of Colorado Boulder, said there may be a very old symbol of a total solar eclipse in New Mexicos Chaco Canyon.

The petroglyph, a picture carved into a rock known as Piedra del Sol in the canyon, shows a circle with looping lines coming off of it, similar to the suns corona. The petroglyph was first discovered during a CU Boulder school trip and is believed to have been a representation of the July 11, 1097 total solar eclipse.

To me it looks like a circular feature with curved tangles and structures, Malville said in a press release. If one looks at a drawing by a German astronomer of the 1860 total solar eclipse during high solar activity, rays and loops similar to those depicted in the Chaco petroglyph are visible.

Malville worked with Jos Vaquero, a professor at the University of Extremadura in Cceres, Spain, to study the petroglyph in relation to the 1097 eclipse using three different sources. The first was using ancient tree rings that were dated back to thousands of years ago. The rings also have traces of isotope carbon-14, which can be correlated back to solar activity at the time. Less carbon-14 means more sunspots, and sunspots are evidence of high solar activity.

The second method the pair used was naked-eye observations of sunspots, and the third method was studying data from northern Europeans about auroral nights, or the northern nights, which is another sign of high solar activity. Their findings about the petroglyph were published in the Journal of Mediterranean Archaeology in 2014.

Piedra del Sol also has a spiral petroglyph that Malville said marks sunrises about 15 days before June solstice as well as a hollowed-out bowl on the east side where Chacoans left offerings. There are two other astronomical art pieces on rocks Chaco Canyon: what is believed to be the A.D. 1054 supernova and a comet, possibly Halleys Comet.

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Is this the first picture of an eclipse? - Astronomy Magazine

The asteroids that populate our solar system are some of the oldest relics of its formation. Studying these relics tells astronomers not only about the conditions in which they and the planets formed, but also about the dynamical history of the solar. Recently, a team of astronomers including researchers from the Southwest Research Institute (SwRI) identified some of the oldest, most pristine asteroids in the main belt, offering an even clearer picture of our nascent solar system.

The work, which was published online August 3 in Science, yielded two important results. First, astronomers spotted a relatively empty spot in the main asteroid belt. The low population in this area means asteroids found in it likely havent undergone significant collisions or evolution, leaving them largely unchanged since their formation. Second, the team identified the oldest family of asteroids found yet, revealing samples of our early solar system for future study.

Nothing is static in our solar system. Over time, asteroids in the main belt (and elsewhere) have undergone collisions that have changed their shape, composition, and other properties. The remnants of these collisions typically end up on similar orbits, creating families of asteroids that astronomers can trace back to one or a few parent bodies.

By identifying all the families in the main belt, we can figure out which asteroids have been formed by collisions and which might be some of the original members of the asteroid belt, said Dr. Kevin Walsh, an astronomer at SwRI and co-author on the paper, in a press release.

Astronomers have already identified more than 100 asteroid families. But the family recently identified was previously unknown, Walsh said. We identified all known families and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids. These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked like just after it formed.

How did they find it? By using a new technique that looked for the edges of asteroid families. Over time, families spread apart, largely due to the effects of sunlight on the asteroids surface, which can impact their orbits. The effect impacts smaller bodies more than larger bodies, causing those small bodies to spread the widest. But by correlating properties such as size and distance, the team was able to reconstruct the shape of a new asteroid family one that formed four billion years ago and stretches throughout the inner part of the asteroid belt.

This family is much darker (less reflective) than other known asteroid families. And those other known families are thought to have formed only about one billion years ago. Thus, the new family is four times older, revealing a much more pristine picture of the early solar system for astronomers to study.

Notably, four billion years ago is a time before the gas giants in our solar system had been locked into their current orbital positions. Thats significant, Walsh said, because The giant planet migration shook up the asteroid belt, removing many bodies, possibly including the parent of this family.

Data on the new family has already indicated that its smallest original members were at least 22 miles (35 kilometers) across. This information has significant meaning for the way in which the asteroids formed, as large initial sizes supports the theory that these bodies formed as dust particles smashed together, quickly creating larger bodies with more gravity.

Now that the team has successfully identified an old, previously unknown asteroid family with their technique, they plan to search the entire asteroid belt for more clues about how the bodies in it formed and the history theyve undergone.

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Astronomers find pristine dark asteroids lurking in the inner belt - Astronomy Magazine

Total solar eclipses like the one that will cross the U.S. on Aug. 21 have captured the attention of astronomers throughout history and have often led to advances in our understanding of how the universe works.

Astronomers have been studying solar eclipses for centuries. In the late 16th and early 17th centuries, Danish astronomer Tycho Brahe and his apprentice German astronomer Johannes Kepler studied eclipses to try to arrive at a rough estimate of the moon's diameter.

In the 19th century, eclipse observations got even more interesting, thanks in large part to advances in scientific instruments like telescopes and spectrometers, devices that let scientists analyze the chemistry of stars and distant planets. In 1868, French astronomer Jules Janssen and English astronomer Norman Lockyer were observing separate solar eclipses when they discovered a new element, which they named helios , after the Greek word for "sun." Today, it's known as helium .

During an eclipse in 1879, American astronomer Charles Augustus Young and Scotland-born astronomer William Harkness both thought they had discovered another new element . But they had actually observed exceptionally hot iron in the sun's corona, the suns outer atmosphere. This was the first indication that the corona is millions of degrees hotter than the sun's surface, a mystery that puzzles astronomers to this day.

Perhaps the most interesting eclipse-based discovery came in 1919. Albert Einsteins theory of general relativity was still being met with skepticism. Under this theory, big gravitational masses like stars and planets warp the fabric of space-time, bending light as it travels through the universe. Einstein didn't have a way of proving it, but luckily, Sir Frank Watson Dyson, the Astronomer Royal of Britain at the time, a senior post in the Royal Households of the U.K., came up with a solution. He plotted the positions of stars that would be near the suns limb, or edge, before a solar eclipse, then measured their positions again during the eclipse. He found that the stars' positions had changed. The only explanation was that the mass of the sun was bending space-time and curving the stars light. They looked to be in different positions, but it was really an effect of the suns mass. It was proof Einstein was right.

So when you watch the eclipse on Aug. 21, which will be visible in parts of 14 states as a total solar solar eclipse and in the rest of the country as a partial solar eclipse, it's a good moment to remember the cosmic event's history of illuminating our place in space.

Amy Shira Teitel is a spaceflight historian who will co-host TIME's livestream of the solar eclipse on Aug. 21

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What Solar Eclipses Have Taught Us About the Universe - TIME

The Search for Extraterrestrial Intelligence, or SETI, has been seeking to improve our ability to intercept and identify intelligent signals from beyond our planet for decades. Now, Laser SETI represents another leap forward, with the ability to search the entire sky all the time for signals that might last just a fraction of a second. This ambitious but achievable project will use cost-effective camera systems at observatories positioned around the globe to put eyes on the sky 24/7. Laser SETI is still in its initial funding stages, and theres still time to get behind this groundbreaking project. And now, you also have the opportunity to have your questions about Laser SETI and the SETI effort answered by a scientist working on the project.

Last month, Astronomy magazine featured a closer look at the Laser SETI project on our website. Now, were pleased to announce that next week, Astronomy.com will host a guest blog by Eliot Gillum, a Laser SETI project scientist and director of the Optical SETI program. And for that blog, were requesting questions from you about Laser SETI, Optical SETI, and the SETI effort. Well pick a few of the top questions we receive for Eliot to address on our Local Group blog.

If you have questions about Laser SETI and the Search for Extraterrestrial Intelligence, please leave them in our comments section below or email them to askastro@kalmbach.com by Tuesday, August 15.

Laser SETIs crowdfunding project will continue through August 18. You can find out more about the project and how to become a contributor to the SETI effort on the Laser SETI Indiegogo campaign page.

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Do you have questions about Laser SETI and the Search for Extraterrestrial Intelligence? - Astronomy Magazine

This artists impression shows the orbits of three of the stars very close to the supermassive black hole at the centre of the Milky Way. Analysis of data from ESOs Very Large Telescope and other telescopes suggests that the orbits of these stars may show the subtle effects predicted by Einsteins general theory of relativity. There are hints that the orbit of the star called S2 is deviating slightly from the path calculated using classical physics. The position of the supermassive black hole is marked with a white circle with a blue halo. Credit: ESO/M. Parsa/L. Calada

A new analysis of data from ESOs Very Large Telescope and other telescopes suggests that the orbits of stars around the supermassive black hole at the centre of the Milky Way may show the subtle effects predicted by Einsteins general theory of relativity. There are hints that the orbit of the star S2 is deviating slightly from the path calculated using classical physics. This tantalising result is a prelude to much more precise measurements and tests of relativity that will be made using the GRAVITY instrument as star S2 passes very close to the black hole in 2018.

At the centre of the Milky Way, 26 000 light-years from Earth, lies the closestsupermassive black hole, which has a mass four million times that of the Sun. This monster is surrounded by a small group of stars orbiting at high speed in the black holes very strong gravitational field. It is a perfect environment in which to test gravitational physics, and particularly Einsteins generaltheory of relativity.

A team of German and Czech astronomers have now applied new analysis techniques to existing observations of the stars orbiting the black hole, accumulated usingESOs Very Large Telescope(VLT) in Chile and others over the last twenty years. They compare the measured star orbits to predictions made using classicalNewtonian gravityas well as predictions from general relativity.

The team found suggestions of a small change in the motion of one of the stars, known as S2, that is consistent with the predictions of general relativity. The change due to relativistic effects amounts to only a few percent in the shape of the orbit, as well as only about one sixth of a degree in the orientation of the orbit. If confirmed, this would be the first time that a measurement of the strength of the general relativistic effects has been achieved for stars orbiting a supermassive black hole.

Marzieh Parsa, PhD student at the University of Cologne, Germany and lead author of the paper, is delighted: The Galactic Centre really is the best laboratory to study the motion of stars in a relativistic environment. I was amazed how well we could apply the methods we developed with simulated stars to the high-precision data for the innermost high-velocity stars close to the supermassive black hole.

The high accuracy of the positional measurements, made possible by the VLTs near-infrared adaptive optics instruments, was essential for the study. These were vital not only during the stars close approach to the black hole, but particularly during the time when S2 was further away from the black hole. The latter data allowed an accurate determination of the shape of the orbit.

During the course of our analysis we realised that to determine relativistic effects for S2 one definitely needs to know the full orbit to very high precision, comments Andreas Eckart, team leader at the University of Cologne.

As well as more precise information about the orbit of the star S2, the new analysis also gives the mass of the black hole and its distance from Earth to a higher degree of accuracy.

Co-author Vladimir Karas from the Academy of Sciences in Prague, the Czech Republic, is excited about the future:This opens up an avenue for more theory and experiments in this sector of science.

This analysis is a prelude to an exciting period for observations of the Galactic Centre by astronomers around the world. During 2018 the star S2 will make a very close approach to the supermassive black hole. This time theGRAVITY instrument, developed by a large international consortium led by the Max-Planck-Institut fr extraterrestrische Physik in Garching, Germany, and installed on the VLT Interferometer, will be available to help measure the orbit much more precisely than is currently possible. Not only is GRAVITY, which is already making high-precision measurements of the Galactic Centre, expected to reveal the general relativistic effects very clearly, but also it will allow astronomers to look for deviations from general relativity that might reveal new physics.

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Hint of relativity effects in stars orbiting centre of galaxy - Astronomy Now Online

A multinational group of astronomers has detected four possible alien worlds circling tau Ceti, which is less than 12 light-years from our Solar System.

Artists illustration of a four-planet system. Image credit: Mark A. Garlick, University of Warwick / Space-art.co.uk.

Tau Ceti is a Sun-like star located just 11.9 light-years away, in the constellation Cetus.

Also known as 52 Ceti, HD 10700 and HIP 8102, the star is very similar to our Sun in its size and brightness, but it is not as active as the Sun.

In 2012, University of Hertfordshire astronomer Dr. Mikko Tuomi and co-authors announced the discovery of five potential planets in the tau Ceti system, labeled tau Ceti b, c, d, e and f.

In a new study, the same team confirmed the existence of tau Ceti e and f and detected two completely new planets, tau Ceti g and h.

We came up with an ingenious way of telling the difference between signals caused by planets and those caused by a stars activity, Dr. Tuomi explained.

We realized that we could see how a stars activity differed at different wavelengths, then used that information to separate this activity from signals of planets.

The four planets are all relatively small, with minimum masses less than 4 times that of Earth. They orbit tau Ceti once every 20, 49, 160 and 642 days, respectively.

Two of them tau Ceti e and f are located on the inner and outer edges of the habitable zone, respectively. They are likely to be candidate habitable worlds, although a massive debris disc around their host star probably reduces their habitability due to intensive bombardment by asteroids and comets.

This illustration compares the four planets detected around tau Ceti (top) and the inner planets of our Solar System (bottom). Image credit: F. Feng, University of Hertfordshire.

Tau Ceti e, f, g and h were detected by observing the wobbles in the movement of the parent star.

This required techniques sensitive enough to detect variations in the movement of the star as small as 30 cm per second.

We are getting tantalizingly close to the 10 cm per second limit required for detecting Earth analogs, said team member Dr. Fabo Feng, also from the University of Hertfordshire.

Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earths habitability through comparison with these analogs.

We are now finally crossing a threshold where, through very sophisticated modeling of large combined data sets from multiple independent observers, we can disentangle the noise due to stellar surface activity from the very tiny signals generated by the gravitational tugs from Earth-sized orbiting planets, added team member Professor Steven Vogt, of the University of California, Santa Cruz.

The data were obtained by using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph, an instrument installed on the 3.6-m telescope at ESOs La Silla Observatory in Chile, combined with the High-Resolution Echelle Spectrometer (HIRES) at the W. M. Keck Observatory on Maunakea, Hawaii.

The teams findings will be published in a paper in the Astronomical Journal. The article is also publicly available at arXiv.org.

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Fabo Feng et al. 2017. Color difference makes a difference: four planet candidates around tau Ceti. AJ, in press; arXiv: 1708.02051

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Four Exoplanets Detected around Nearby Star Tau Ceti - Sci-News.com

MORAGA Dr. Ronald Olowin, a well-known Saint Marys College School of Science professor and astrophysicist and member of the faculty there since 1987, died Saturday at age 72.

A Lafayette resident, Olowin a devout Catholic often gave lectures on the complex relationships between politics, religion, science and art, starting from the era of the historical Christ.

He was a member of the executive committee for the Inspiration of Astronomical Phenomenon consortium, which holds international meetings to explore the influence of astronomical phenomena on art, literature, myth, religion and history.

With a National Science Foundation grant and a major donation from Saint Marys alumnus and Bay Area dentist Louis Geissberger, Olowin was central to establishing the Norma Geissberger Observatory, where a research telescope was installed in 2004 on Observatory Hill near campus.

He also worked to deepen the colleges relationship with Moraga and the other Lamorinda cities, giving talks about the intersection of science and religion at his church, St. Perpetua Catholic Community in Lafayette, at Berkeleys Graduate Theological Union, and at installments of the Science Cafe series of discussions at the Lafayette Library.

A native of Pennsylvania, Olowin studied geophysics and astronomy at the University of British Columbia and worked at an observatory in South Africa before coming to Saint Marys 30 years ago.

Funeral services will be at 10:30 a.m. Saturday, Aug. 26 at St. Perpetua Church; a vigil service will he held the night before Friday, Aug. 25 at 7 p.m. in the Saint Marys College Chapel.Donations may be made in Rons honor to the Ron and Mary Olowin Memorial Gift, for the support of the Christian Brothers educational ministry in Myanmar under Brother Ling John. Send such donations to the De La Salle Institute (DLSI), 4401 Redwood Road, Napa CA 94558.

Donations may also be made to the St. Perpetua Church Capital Campaign, for the purpose of building a new social hall for the parish. Those contributions can be sent to St. Perpetua Church, 3454 Hamlin Road, Lafayette CA 94549.

Read more from the original source:

Ron Olowin, Saint Mary's physics, astronomy professor, dies - East Bay Times

The Sun is the closest star to Earth at a mere 93 million miles (150 million kilometers) away. Despite the fact that you can feel its heat on your skin and its disk appears as large as the Full Moon in the sky, the Sun still largely remains an enigma. For all that astronomers have learned about our planets nearby host star, many questions and uncertainties remain. Now, though, one of those questions has been answered: the rotation rate of the Suns core.

An international team of astronomers using the Global Oscillations at Low Frequencies (GOLF) instrument aboard the ESA/NASA Solar and Heliospheric Observatory (SOHO) satellite have accurately measured the speed at which the Suns core rotates for the first time. That rotation rate is once per week. Their results, including the novel method they developed to measure this rotation rate, are published in Astronomy & Astrophysics.

The SOHO satellite has been studying the Sun for more than two decades. Its GOLF instrument records oscillations, which are wavelike changes in the gases of the Suns atmosphere that reveal information about its inner structure. GOLF records these changes at the level of the Suns surface every 10 seconds; solar astronomers then look at the signals over time to infer details about the activity deeper within the star. Studying the Sun this way is similar to studying the way waves caused by earthquakes propagate through the Earth, which tells scientists about the structure that lies beneath our feet.

To study the Suns core, the team examined an aspect of the oscillations visible at the Suns surface that reflects the time it takes for waves to travel through the center of the Sun. They found that the thermonuclear core rotates once per week, which is nearly four times faster than the rotation rate of the middle and outer layers of the star.

Using this new information, astronomers will be able to refine their models of the Suns current and past behavior, as well as determine more accurately its composition and the structure of its layers and magnetic field.

Read the rest here:

The Sun's core rotates faster than its surface - Astronomy Magazine

IRVINE Astronomers from UC Irvine have concluded that as many as 100 million black holes exist in our galaxy a tally far more than previously believed and shocking even to the three researchers.

The findings, while surprising, dont figure to affect life on earth or offer any immediate change in thinking about how the universe was formed and continues to evolve.

Its not like we need to go out and buy black hole insurance soon; not like were in danger of being sucked into a black hole any more than we were before, said James Bullock, UCIs chairman and professor of physics and astronomy and one of the researchers on the project.

There are wonderless giant objects lurking out there, Bullock said of black holes. Its just amazing that the universe was created out of things like this.

The trios discovery grows out of the 2015 detection of evidence showing that two black holes, each the size of 30 suns, collided to form a single one some 1.3 billion years ago. In response to thatground-breaking news which confirmed a key part of Einsteins theory of relativity the three UCI astronomers launched their study to determine how many black holes there are in the Milky Way.

In Monday interviews, Bullock, Manoj Kaplinghat, a physics and astronomy professor, andOliver Elbert, who in July earned a Ph.D. from UCI, said they couldnt even venture guesseson how many black holes existed.

The three co-authored a research paper on their findings that appears in the current issue ofMonthly Notices of the Royal Astronomical Society.

For more than 18 months, the trio researched existing data about galaxies and stars, and crunched mathematical formulas, creating their cosmic inventory.

It was an amazing exercise we were able to do, given what we know and what we dont know, to come up with a number that was pretty accurate, Bullock said.

A black hole is a star that has burnt off all of its fueland collapsed. The gravity in a black hole typically becomes so strong that light cant escape, rendering the space where the star once existed invisible.

In addition to counting our galaxys black holes, the trio set out to shed light on the elusive phenomenon of black holes colliding. The collision tracked in 2015 was the first time the phenomenon had been proven.

Of the 100 million black holes, Bullock, Elbert and Kaplinghat determined that 10 million are each the size of 50 suns. Some could collide in the near future.

Right now, we know these black hole mergers are occurring in some broad swath of the sky, but not with much precision, Bullock said. Theres hope well be able to triangulate their positions in the sky (and)begin to figure out what galaxy theyre merging in. In the next decade or so, Elbert said, astronomers should figure out the answer.

Its definitely something I will be keeping my eye on, as we get more information coming in from future detection, he said. I plan on coming back to this, revisiting some of our predictions.

Said Bullock: The fun thing about research is when you find out one answer, it always opens up three or four other questions.

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UC Irvine astronomers make a hundred million discoveries black ... - OCRegister

An unusually bright storm system nearly the size of Earth has been spotted in the atmosphere of Neptune, baffling researchers because it is located near the ice giants equator.

This image from the Keck Telescope shows an extremely bright, nearly circular storm system near Neptunes equator. Image credit: Ned Molter & Imke de Pater, University of California, Berkeley / C. Alvarez, W. M. Keck Observatory.

This giant storm system is unusually bright and is about 5,600 miles (9,000 km) in length, or one-third the size of Neptunes radius, spanning at least 30 degrees in both latitude and longitude.

The storm was discovered earlier this year by Ned Molter, a graduate student at the University of California, Berkeley, in images taken by an optical/infrared telescope at W. M. Keck Observatory on Maunakea, Hawaii.

Seeing a storm this bright at such a low latitude is extremely surprising. Normally, this area is really quiet and we only see bright clouds in the mid-latitude bands, so to have such an enormous cloud sitting right at the equator is spectacular, Molter said.

He observed the system getting much brighter between June 26 and July 2.

Historically, very bright clouds have occasionally been seen on Neptune, but usually at latitudes closer to the poles, around 15 to 60 degrees north or south, said Professor Imke de Pater, also from the University of California, Berkeley.

Never before has a cloud been seen at, or so close to the equator, nor has one ever been this bright.

At first, the scientists thought the storm system was the same Northern Cloud Complex seen by the NASA/ESA Hubble Space Telescope in 1994, after the iconic Great Dark Spot, imaged by NASAs Voyager 2 in 1989, had disappeared.

But measurements of its locale do not match, signaling that this cloud complex is different from the one Hubble first saw more than two decades ago, Professor de Pater said.

Images of Neptune (upper row June 26, lower row July 2) revealed an extremely bright storm system near Neptunes equator (labeled cloud complex in the upper figure). Image credit: Ned Molter & Imke de Pater, University of California, Berkeley / C. Alvarez, W. M. Keck Observatory.

A massive, high-pressure, dark vortex system anchored deep in Neptunes atmosphere may be whats causing the colossal cloud cover.

As gases rise up in a vortex, they cool down. When its temperature drops below the condensation temperature of a condensable gas, that gas condenses out and forms clouds, just like water on Earth. On Neptune we expect methane clouds to form.

As with every planet, winds in Neptunes atmosphere vary drastically with latitude, so if there is a big bright cloud system that spans many latitudes, something must hold it together, such as a dark vortex. Otherwise, the clouds would shear apart.

This big vortex is sitting in a region where the air, overall, is subsiding rather than rising. Moreover, a long-lasting vortex right at the equator would be hard to explain physically, Professor de Pater said.

If it is not tied to a vortex, the system may be a huge convective cloud, similar to those seen occasionally on other planets like the huge storm on Saturn that was detected in 2010.

Although one would also then expect the storm to have smeared out considerably over a weeks time.

This shows that there are extremely drastic changes in the dynamics of Neptunes atmosphere, and perhaps this is a seasonal weather event that may happen every few decades or so, Professor de Pater said.

Link:

Giant, Extremely Bright Storm System Spotted in Neptune's Atmosphere - Sci-News.com

Radnor >> On Monday, Aug. 21 a full solar eclipse when the moon blocks the view of the sun will sweep across the United States. Residents in the Philadelphia area will be treated to a 75 percent partial eclipse.

Among those who are eagerly anticipating the eclipse is Villanova University Astronomy Professor Edward Guinan, who plans to travel to Nebraska, where he has relatives, to see the full solar eclipse. This will mark the fifth total solar eclipse that the veteran professor, who has taught at VU for 47 years, has observed.

The really big deal is to see a total one, said Guinan, who is known internationally as an astrophysics expert in solar activity and flares. Over the years, hes journeyed to North Carolina (1970), Turkey (2006), Romania (1999) and Nova Scotia (1972) the latter eclipse made famous in the Carly Simon song, Youre So Vain. He recalled that eclipse as being a particularly beautiful event that he watched from a beach.

This one is convenient, said Guinan. It goes right across the U.S. A lot of my students havent seen any (eclipses).

The total eclipse is just amazing, said Guinan. It gets pretty dark. The stars come out. Birds roost. It only lasts a few minutes. Of course, you can get clouded out and then it just gets dark.

With satellites now circling the planet, eclipses are not as scientifically valuable as they were in earlier times but the phenomenon still yields scientific information. In the past, the 1919 solar eclipse proved the general theory of relativity posited by Albert Einstein, that mass bends space and time. Also, during an 1867 eclipse scientists discovered the then unknown element Helium.

While in Nebraska, Guinan plans to fly drones to look at the shadow created by the eclipse and also take part with a nationwide group of scientists taking pictures of the magnetic streamers in the suns corona that are visible during the 2 minute totality as the eclipse travels across the United States. During this time, bright stars can be seen and planets like Mercury, Mars and Jupiter. When previous eclipses occurred, the solar corona has been shown to be 2 to 3 million degrees. Since light from the corona is about 1 millionth as bright as the surface of the sun, it can only been seen from the Earth during a total eclipse.

Guinan emphasized how dangerous it is to look directly at the sun during the eclipse and warns people against that. People can see the eclipse safely with special glasses or by using a pinhole in a cardboard to project the suns image onto a paper. Also, its safe to use solar telescopes or solar binoculars or those instruments with approved solar filters. Otherwise, staring at the sun to view the eclipse can cause blindness, he said.

Astronomers have been able to predict eclipses since ancient times and people told various myths to explain the phenomenon, such as that a monster was trying to eat the sun. In ancient China, a ruler once ordered two astronomers to be beheaded when they failed to predict an eclipse. It was the ancient Greeks who figured out the mathematics involved when the earth, moon and sun line up on the same plane causing an eclipse, he said.

If the weather cooperates on Aug. 21, the eclipse should be visible between 1:20 p.m. and 4 p.m. At 2:44 p.m., 75 percent of the sun will be blocked by the moon. Meanwhile, Villanovas Department of Astrophysics and Planetary Science will host a Solar Eclipse Open House for University faculty, students and staff.

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Villanova astronomy professor gears up for solar eclipse - Main Line

A supernova is the largest explosion you might ever see if you ever get to see it! Its the death of a star, and stars go out with a bang. Theyre still mostly a mystery to science. Its possible to understand the basic processes behind them, but predicting them accurately or getting a solid understanding of the chemistry has proven difficult.

Weve taken the first steps toward that goal though. Thanks to improvements in technology, computer models have been able to replicate what exactly happened in SN 1987A: a supernova that occurred 30 years ago. The hope is that by better understanding supernovae, we can learn about the creation of the stars and planets that fill the universe and, therefore, the development of life.

What is a Supernova? If you are lucky enough to see a supernova, it probably occurred in a different galaxy. The Milky Way has plenty, but theyre much harder to see here thanks to the dust, gas, and other astronomical objects blocking our view. Theyre still the brightest, most exhilarating explosions that occur in our galaxy. A single supernova can appear brighter than the galaxy it resides in for a period of time, making it the brightest object in the sky. After the initial explosion, the remnant that you can see is the explosion of debris from the star. There are two ways for a star to reach this point, but both occur at the end of its lifetime.

The Death of Stars Although here on Earth we live in a single-star system, binary star systems are common. (With another 70 times its mass, Jupiter could have been the second star in our system. Instead, it became a planet.) In a binary star system, one star often reaches the end of its life first. Instead of exploding, smaller stars like our Sun will puff up into red giants and then shed their outer layers. Eventually, the core shrinks back down and condenses into a white dwarf. Even smaller stars skip the red giant phase and burn directly down to white dwarfs.

A white dwarf has a significant gravitational pull. As its companion goes through its own red giant phase, some of the material it sheds can be pulled onto the white dwarf. As more mass gets sucked onto the white dwarf, its equilibrium gets thrown off, and it will eventually explode, creating a supernova. This is only one of two ways that supernovae form, at least that we are aware of.

For the largest stars, there is no red giant or white dwarf stage. Instead, the stars simply burn through all of their available hydrogen and are no longer able to use fusion to remain stable. This causes the inner core to collapse, and the still active matter on the outer shell of the star falls into the center, then rebounds in a supernova.

Either way, a supernova spells death for a star.

Mapping Death While we think we have a good understanding of how supernovae form, we dont have a good grasp of what happens inside them. This is mainly due to the fact that weve never been able to observe one from the inside, or even up close which is good; you do not want to be inside one because youd be dead. What we do know is that the largest explosions in the known universe put physics in some weird predicaments. They pop out new elements that make up everything else, including you and me. When you hear someone say that youre made of star stuff, they arent making that up. The deaths of stars have given us every naturally occurring element in creation. So its understandable that astronomers want to find out what happens.

How were scientists able to map this supernova, exactly?

Astronomers have continued to observe the changes in a supernova observed in 1987, called SN 1987A, located in the Large Magellanic Cloud. SN 1987A is an optimal candidate to study since its not yet strongly affected by its surroundings.

Recently, a team from the University of Virginia used the Atacama Large Millimeter/submillimeter Array (ALMA) to study the supernova. ALMA is an array of radio telescopes designed to work together as an interferometer to process information. Astronomers chose ALMA because of its ability to see in submillimeter wavelengths. However, ALMA is susceptible to radio frequency interference. It is imperative that scientists block out all background interference since radio frequency devices are particularly susceptible to a wider variety of noise that can skew data. If its electronics werent protected, signals could cross and prevent discoveries. The array depends on all 66 antennas and accompanying electronics synchronizing down to a millionth of a millionth of a second. No pressure!

Because the telescopes work together at short submillimeter wavelengths, they are able to create the highest-resolution images. The inner core of SN 1987A previously eluded astronomers because gas and dust blocked out other methods of observation. ALMAs ability to see these fine details helped astronomers finally see past the obstructions. Then, they created 3-D maps of the elements and molecules found within the collapsed supernova with the data collected. In the last 30 years, SN 1987A had time to cool down and start forming new molecules. Now we have the first results of what kinds of elements form as the result of one of these explosions.

So, what did astronomers find?

View original post here:

Astronomers just mapped the inside of a supernova - Astronomy Magazine

People nationwide are rushing to buy eclipse glasses with just two weeks left before the historic Aug. 21 event.

But buyer beware.

The American Astronomical Society is warning on its website that the market is being flooded with counterfeit eclipse glasses.

The AAS previously advised people to look for evidence that the glasses comply with international safety standards for filters of direct viewing of the sun by ensuring the following was printed on the glasses: ISO 12312-2.

Related: Best places to watch the Great American eclipse.

But now the marketplace is being flooded bycounterfeit eclipse glassesthat are labeled as if theyre ISO-compliant when in fact they are not, AAS said.Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers havent been properly tested.

The American Astronomical Society says it is no longer enough to check for ISO certification on eclipse glasses. Make sure they come from a reputable vendor also.

You cannot watch the eclipse the first in 99 years to cross the entire U.S. without special glasses or you can do irreversible damage to your eyes, including going blind. Although the sun is no brighter during an eclipse than on a regular day, it is more comfortable to look at, meaning you can stare at it longer and damage your eyes.

Related: Your eyes will fry under normal sunglasses during eclipse.

Regular sun glasses are not enough to keep out the harmful rays of the sun.

What you absolutely shouldnotdo is search for eclipse glasses on the internet and buy whatever pops up in the ads or search results, AAS said.

AAS is now suggesting people ensure their glasses are ISO certified and come from reputable vendors that it has verified and listed on its website.

The manufacturers listed are ones the AAS Solar Eclipse Task Force has had previous experience with as well as companies whose products have been certified safe by authorities we recognize and whose certification we have confirmed to be genuine.

NASA also recommends the glasses not be used if they are older than three years or are scratched.

The problem with fakes is that you cant know if theyre letting unsafe levels of solar ultraviolet and/or infrared radiation into your eyes, said Richard Tresch Fienberg, a press officer with AAS. Youd never know until its too late, because our retinas dont have pain receptors.

I bought several pairs of glasses from different vendors on Amazon before checking the approved list. I didnt realize one set was not on the list. The companys Amazon site is no longer working and neither is its Facebook page. The brand is Cosmos Eclipse Glasses by POGO Industrial CO. Im trying to reach the company.

Fienberg said he has not heard of the brand.

I bought some counterfeits in a New Hampshire country store yesterday, Fienberg said this morning. Theyre printed almost the same as real ones from American Paper Optics, but there are numerous telltale signs that theyre fake.

American Paper Optics glasses have rectangular lenses with metal on one side.

You cannot check yourself to see if your eclipse glasses are safe. But there are signs they are NOT safe.

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Fake eclipse glasses 'flooding' market, astronomy group says - Palm Beach Post (blog)

Recently, I wrote about a collaboration between amateur and professional astronomers: Its purpose is to use the expertise many amateur astronomers have in image processing to create better and more dynamic images of planets to support planetary science and spacecraft.

The results were spectacular. But they were using a 1-meter telescope; small by pro standards these days, but still pretty big, and located on a distant mountaintop, as well. What happens when you try something like this with a sub-1-meter scope?

Well, let me introduce you to the work of Rolf Wahl Olsen, a Dane who now lives in New Zealand. Armed with a 32-centimeter telescope he built himself, he takes images that are of superior quality. But hes not content to just take pretty pictures: He goes after unusual objects, ones that are very difficult to capture, and, to be honest, ones I wouldve thought would be well beyond the capability of small telescopes. But, again and again, Rolf flips my expectations around.

His latest work is crushing my brain. Using his home-built scope, he managed to get an image of a galaxy billions of light years away. And not just any galaxy, but the Horseshoe Galaxy: one of the finest examples of gravitational lensing found, and one so small and faint and bizarre it was only discovered in 2007!

Thisll take a moment to explain

The wide-angle image is lovely, with red and blue stars dazzling. You can also see quite a few fuzzy, distant background galaxies, huge cities of stars like our Milky Way but reduced by distance to faint smears.

But if you look carefully, you can see one (outlined) thats different than the rest. Even zoomed in (upper right) the Horseshoe Galaxy at first doesnt look like much; just a red star-like object with a faint, discolored halo around it. An image taken by Hubble (bottom right) shows it more clearly, though its still odd-looking, like a blue galaxy smeared around a red one.

Because thats exactly what it is. Or really, what it looks like. What you are seeing here is an amazing collision of geometry, relativity, gravity, and luck.

Ive had many occasions lately to write about gravitational lensing. This is when the light traveling through space from a distant background source is bent by the gravity of some other object. Einstein, himself, came up with the idea that what we perceive as gravity is really a warping of space. Its similar to the effect of putting something heavy like a bowling ball on a mattress. The mattress bends, and if you roll a marble past it, the path of the marble will curve.

It light passes a massive object like a galaxy, the path it takes will bend. Anything that bends light is called a lens, so we call this a gravitational lens, and they can cause all kinds of weird effects, including magnifying the brightness of the object as well as distorting its shape. It depends on the mass of the lensing object, how its distributed, and the precise alignment of the background source, the lens, and the observer (us).

If the Earth, the lensing object, and the more distant source are in a perfect line, the lensed source will appear like a circle, a ring, around the lensing object. Thats because light initially sent out by the background galaxy in a direction not exactly toward us can get bent enough to head straight at us. So, light sent slightly to the left, or right, or above, or below (in terms of what you see in a photo, I mean) by the galaxy will all get bent toward us, and what you wind up seeing is a ring. In fact, we call them Einstein Rings.

Thats what youre seeing with the Horseshoe galaxy! Now, get this: The blue galaxy, itself, is a staggering 11 billion light years away, more than three-quarters of the way to the edge of the observable Universe! That means were seeing it as it was 11 billion years ago, when it was young. At that time, it was actively making stars, so it appears quite blue due to the massive, hot, and very luminous blue stars that were being born.

The light from that galaxy traveled a long way to get here. But, on the way to us, it got distorted: A very massive galaxy, called LRG 3-757, was in the way. This is a massive galaxy, perhaps ten times as massive as our own Milky Way, about 4.7 billion light years away (so, less than half the distance to the Horseshoe) and possesses a strong gravitational field. It bent the light from the more distant galaxy, and we see that as a nearly complete circle of blue light around the red galaxy. It goes about 300 around, making it one of the more complete Einstein Rings ever found.

Mind you, the Horseshoe galaxy is probably a lovely spiral galaxy, but we see it as a circle due to this distortion. It was discovered in a survey by astronomers looking for gravitational lenses, and follow-up observations determined its nature. These are important objects, because they can tell us a lot about the mass and distribution of matter in the lensing galaxy, which would otherwise be very difficult to determine.

And thats why its staggering that Rolf was able to detect it! These galaxies are tremendously far away, very faint, and so close together that being able to separate them is a feat unto itself. Of course, the Hubble image is clearer and brighter, but it has a lot of advantages: it uses a mirror over seven times wider than Rolfs scope, and its up in space above our soupy atmosphere.

But the fact that Rolf could capture this at all is remarkable! He took a total of 9.5 hours of exposures to create it (the Hubble image is about three hours total). The camera he used, the QSI 683wsg, costs about $4000, and is very high quality. Im not sure how much the Wide Field Camera 3 on Hubble cost, but the Hubble camera I worked on, called STIS, was around $100 million. So, that also may give Hubble something of an unfair advantage.

Still, they compare pretty well, I think, given the different circumstances. Close enough, at least. And you know what they say about Horseshoe galaxies and hand grenades.

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Horseshoe galaxies and hand grenades - SYFY WIRE (blog)

The sun and moon will be the topics of a program at 10 a.m. Monday, Aug. 14, at the MSU St. Andrews Center, 1910 W. St. Andrews Road (the next driveway west of the Grace A. Dow Memorial Library).

The program will begin with a short presentation describing different telescopes, along with information on the sun and the moon, including some discussion of eclipses. An observation session will follow as participants view the sun through a telescope, using special filters designed for solar viewing. People never should look at the sun through a telescope without a solar filter.

Participants should be able to see sunspots if they are in view asa well as the effects of earth's atmosphere as it warms up during the day.

The moon will also be in the sky that morning. People can compare daytime vs. nighttime viewing. That day, the moon will be in last quarter phase. Many craters will be visible, as well as some of the lunar "seas" and the "Ocean of Storms."

The program is recommended for elementary-age children and above, and their families, but all are welcome. There is no cost.

This program is made possible in part by support from the Dow Chemical Co. Foundation.

In case of clouds or bad weather, the event will move to 10 a.m. Wednesday, Aug. 16.

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Family astronomy day coming to MSU center in Midland - Midland Daily News