Weather-wise, spring has hopefully sprung as we begin April. But did you know that many of the prominent winter constellations can still be observed? If the cold and snowy conditions of February and March prevented you from exploring the winter sky, its now time to say farewell to some star patterns that often get overlooked during mid-winter in our region of the country. With public night viewing at Seagrave Observatory and Ladd Observatory closed due to COVID-19, even I did not observe my winter sky friends. Its difficult to set up a telescope in ones backyard with 18 inches of snow on the ground.

Once this column is published, I want you to scan the western sky after sunset to bid goodbye to many of the skies brightest star patterns. See the accompanying star map. Start with Perseus toward the northwest, then move your gaze south (to the left). Here you will encounter Taurus, with the prominent star clusters named the Pleiades (aka the Seven Sisters) and the Hyades. While a binocular view of the Pleiades does show a nice image, the ideal sight you want to achieve is with a telescope under low magnification so the entire cluster fits into the field of view. In a dark, moonless sky, the Pleiades remind me of sparkling diamonds scattered upon black velvet.

Above Perseus and Taurus, youll find Auriga. To the south (left) of Taurus youll encounter the Mighty Hunter Orion. And further to the left will be Canis Major, home of Sirius, the brightest star we can see in our sky other than the sun. Youll find Gemini, the twins above Orion, and this star pattern will be the last of the winter constellations to set below the horizon.

If you dont explore anything else in this region of the heavens before the constellations set, make an effort to observe the Orion Nebula if you havent already done so this past winter season. Usually, the local observatories would have focused on this beautiful region of stellar dust and gas for many weeks, but closures prevented that activity during the winter of 2020-2021. In past columns over the years, I have highlighted this remarkable region of space where new stars are in the process of being born. Following is a brief description.

The grandeur of Orion resides in the region of his sword. Using binoculars, youll see a wispy, hazy patch of green light enshrouding the stars. Using a telescope even under low magnification will reveal a greenish tinged nebula of dust and gas the magnificent Orion Nebula. I never tire of observing this vast dust cloud, often imagining what this region of space will look like when upwards of 1000 stars will be born here.

Mars Still Visible

Due to the orbital paths of Mars and the Earth, when Mars is visible it remains so for an extended period of time. The contrary is also true. When Mars disappears from view it remains hidden for an extended period of time. Right now, you can still observe Mars, as it resides in the constellation of Taurus. See star map. You may recall that Mars and the Earth had a close encounter last Oct. 6, when our two worlds were only 38.6 million miles away from one another. At that time Mars was a very bright pumpkin orange in the night sky and its disk was large enough to see a wealth of detail using a telescope. On April 1 that distance will be 164.5 million miles. Mars will be much dimmer than it was back in October. In fact, it will now be fainter than Taurus brightest star Aldebaran. While the planet will appear small even in a modest-sized telescope, perfect seeing conditions may allow one to discern a Martian surface feature or two. It doesnt hurt to try.

April Lyrids Meteor Shower

I always look forward to a decent display of shooting stars. While the upcoming April Lyrids meteor display on the night of April 21-22 is not a blockbuster event, one can potentially observe upwards of 20 meteors per hour in a dark country sky. The Lyrids appear to radiate outward from an area of sky on the Lyra-Hercules border near the bright star Vega, which will be about 45 degrees (halfway between the horizon and zenith) above the eastern horizon at midnight and well-placed for observing.

A bright waxing gibbous Moon, about 70% illuminated, will somewhat reduce visibility of the fainter meteors. However, it will be located more than 100 degrees away to the west in the constellation of Leo, to the right of the backwards question mark asterism. While still a nuisance light source, the moon shouldnt compromise your observing session. Try to block its brightness using a building or some trees.

These swift and bright meteors disintegrate after hitting our atmosphere at a moderate speed of 29.8 miles per second. They often produce luminous trains of dust that can be observed for several seconds. The moon will set just before 4 a.m. EDT, leaving a little more than an hour of moonless sky before dawns early light will begin to overwhelm the stars and the meteors.

Best of luck in all your observing endeavors.

The author has been involved in the field of observational astronomy in Rhode Island for more than 35 years. He serves as historian of Skyscrapers Inc., the second oldest continuously operating amateur astronomical society in the United States.

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View On Astronomy: April means it's time to say farewell to winter constellations - The Independent

Astronomers havesearched the entire Milky Way to identify the safest places to live.It turns out, we're in a pretty good spot.

But if the past year has made you feel ready to relocate to another planet, you might want to looktoward thecenter of the galaxy, according to the new research.

The new findings were made by a group of Italian astronomers, who studied locations where powerful cosmic explosions may have killed off life. These explosions, such as supernovas and gamma-ray bursts, spew high-energy particles and radiation that can shred DNA and kill life. By this logic, regions that are more hospitable to life will be the ones without frequent explosions, the astronomers reasoned.

"Powerful cosmic explosions are not negligible for the existence of life in our galaxy throughout its cosmic history," said lead author on the new study, Riccardo Spinelli, astronomer at the University of Insubria in Italy. "These events have played a role in jeopardizing life across most of the Milky Way."

Related: 11 fascinating facts about our Milky Way galaxy

In addition to finding the deadliest hotspots, the astronomers also identified the safest places throughout the galaxy's history, going back 11 billion years. The results show that we're currently at the edge of a wide band of hospitable real estate. But in the Milky Way'syouth, the galaxy's edges were a safer bet.

Many factors make a planet habitable. For instance, planets need to be in a Goldilocks zone, where heat and activity from their host star isn't too much or too little it's just right. But in addition to these local conditions, life also has to combat harmful radiation coming from interstellar space.

Powerful cosmic events, such assupernovas and gamma-ray bursts, stream dangerous, high-energy particles at nearly the speed of light. Not only can they kill all the lifeforms we know about, but these particles can also strip entire planets of their atmospheres. After such an event, the scientists believe that planets orbiting nearby star systems would be wiped clear of life.

Related: The 9 real ways Earth could end

"For planets very close to the stellar explosion it is plausible that there is a complete sterilization," Spinelli told Live Science. "In those far away, a mass extinction is more likely."

The authors wrote in the study that a nearby gamma-ray burst may have played a leading role in theOrdovician mass extinction event around 450 million years ago the second largest in Earth's history. While there is no concrete evidence linking a specific gamma-ray burst to this extinction event, the authors think it could be likely, given Earth's position in the galaxy.

Using models of star formation and evolution, the astronomers calculated when specific regions of the galaxy would be inundated with killer radiation. Early on in the galaxy's history, the inner galaxy out to about 33,000 light-years was alight with intense star formation, which rendered it inhospitable. At this time, the galaxy was frequently rocked by powerful cosmic explosions, but the outermost regions, which had fewer stars, were mostly spared these cataclysms.

Until about 6 billion years ago, most of the galaxy was regularly sterilized by massive explosions. As the galaxy aged, such explosions became less common. Today, the mid regions, forming a ring from 6,500 light-years from the galaxy's center to around 26,000 light-years from the center, are the safest areas for life. Closer to the center, supernovas and other events are still common, and in the outskirts, there are fewer terrestrial planets and more gamma-ray bursts.

Luckily for us, our galactic neighborhood is getting more and more life-friendly. In the long-term galactic future, there will be fewer extreme events nearby that could cause another mass extinction.

The new paper's conclusions seem reasonable at first glance, Steven Desch, an astrophysicist at Arizona State University, told Live Science.

"I'm pleased to note that they do seem to put [the research] in a rigorous framework and have realistic expectations about what a gamma ray burst would do, and account for factors that sometimes people forget," such as how the energy and material released by gamma-ray bursts isnt equal in all directions, said Desch, who was not involved with the new work. "I haven't gone through their numbers in detail, but at first glance it's reasonable."

The new research, published in the March issue of the journal Astronomy and Astrophysics, might one day help astronomers decide where to search for habitable exoplanets. But for now technology limits astronomers to only searching nearby areas, Desch said.

Originally published on Live Science.

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Astronomers find the 'safest place' to live in the Milky Way - Space.com

Artificial satellites and space junk orbiting the Earth can increase the brightness of the night sky, researchers have found, with experts warning such light pollution could hinder astronomers ability to make observations of our universe.

There are more than 9,200 tonnes of space objects in orbit around the Earth, ranging from defunct satellites to tiny fragments, according to the European Space Agency (ESA). Now it seems space junk not only poses a collision risk but, together with other space objects, is contributing to light pollution.

Writing in the Monthly Notices of the Royal Astronomical Society, researchers describe how sunlight that is reflected and scattered from space objects can appear as streaks in observations made by ground-based telescopes.

Because the streaks are often comparable to or brighter than objects of astrophysical interest, their presence tends to compromise astronomical data and poses the threat of irretrievable loss of information, the team writes.

But for some instruments, the impact could be greater still. When imaged with high angular resolution and high sensitivity detectors, many of these objects appear as individual streaks in science images, they write. However, when observed with relatively low-sensitivity detectors like the unaided human eye, or with low-angular-resolution photometers, their combined effect is that of a diffuse night sky brightness component, much like the unresolved integrated starlight background of the Milky Way.

Calculations in the report suggest this glow could reach up to 10% of the natural night sky brightness a level of light pollution previously set by the International Astronomical Union (IAU) as being the limit that is acceptable at astronomical observatory sites.

While the researchers say the idea of a natural level of brightness has its own difficulties, they stress further research is necessary, adding that the situation could become worse as further satellites, including mega-constellations, are launched.

Greg Brown, a Royal Observatory astronomer who was not involved in the study, said light pollution was a big problem for astronomers.

Telescopes like the soon-to-be-operational Vera C Rubin Observatory are expecting vast contamination of their images from just the mega-constellations expected in the next few years, which will be difficult and costly to compensate for and do seriously risk scientists missing out on key scientific discoveries, he said.

While Brown said it was unclear whether the assumptions made in the study held true, given changes in satellite design and the difficulty of estimating small space debris, he said astronomical observations would be increasingly affected by such light pollution.

This is definitely the time to be concerned about the future of both professional and amateur astronomy, he said.

Prof Danny Steeghs of the University of Warwick said there was a balance to be struck between the benefits of satellites and their impact on our ability to study the night sky, but agreed light pollution was likely to be a growing, and escalating, problem.

We can, as astronomers, remove or reduce the direct impact on our data somewhat by employing image processing techniques, but of course it would be a lot better if they are not there for starters, he said.

Fabio Falchi, from the Light Pollution Science and Technology Institute in Italy, said the problem was global. The distribution of the space debris is fairly uniform around our planet, so the contamination is already present everywhere, he said, suggesting those responsible for the problem should help to solve it.

Maybe Elon Musk can put his engineers at work to find out a solution, at least to counterbalance a little the damage that his Starlink mega-constellation of satellites is going to make to the starry sky, he said.

While projects have recently begun to clean up space junk, Steeghs said one difficulty was that small fragments could be tricky to sweep up yet could nonetheless contribute to the light pollution.

Chris Lintott, a professor of astrophysics at the University of Oxford, also stressed the need for action. It does seem that simple efforts like building satellites out of darker materials might be very helpful, and I hope operators will take such steps as soon as possible, he said.

Link:

Light pollution from satellites 'poses threat' to astronomy - The Guardian

In March 2020, the Vera C. Rubin Observatory sat partially erected, perched on Chiles Cerro Pachn in the foothills of the Andes Mountains. The Observatory had halted construction of the 8.4-meter telescope and its associated buildings due to the coronavirus pandemic. By October 2020, with safety precautions in place, construction teams began to slowly return to the mountain. Earlier this month, just one year after its unexpected closure, the Rubin Observatory reached a major milestone when crew used a crane to lower the top end of the telescope, weighing approximately 28 tons and measuring 10 meters in diameter, through the observatorys open dome and into its place on the telescope. This was one of the last remaining heavy pieces to be added to the telescope as the project nears completion and looks forward to beginning regular observations in 2022.

Once in operation, the Rubin Observatory will survey the sky above it, capturing images every few nights to create a catalog of data and a map of the visible universe. Astronomers will use this accumulation of roughly 20 terabytes of data each night, enough to hold the equivalent of four million of your favorite songs, to push our scientific understanding of the structure and evolution of the universe.

Initially called the Large Synoptic Survey Telescope, the Vera C. Rubin Observatory was renamed to honor a pioneer in astronomy, particularly in the field of dark matter, one of the many mysteries the new observatory is expected to help probe. Beginning in the 1960s, Dr. Vera Rubin used a new instrument designed by Kent Ford to study the motion of galaxies. Rubin discovered that the stars in the galaxies she observed orbited faster than expected. One explanation for this discrepancy was that there was more mass in the galaxy than could be seen in the stars alone. Rubins observations helped provide the best observational evidence that the universe is not only composed of ordinary matter, but is actually dominated by dark matter.

In 2019, two U.S. House of Representative members, Eddie Bernice Johnson and Jennifer Gonzlez-Coln, introduced the congressional bill to rename the observatory, the text of which noted Rubins pioneering astronomical work, but also the barriers she faced because of her gender. Princeton University, Rubins preferred choice for graduate work, did not allow women to apply to its programs and the astronomical community largely ignored Rubins research early in her career. Eventually she succeeded in securing a position at the Carnegie Institution of Washington and became the first woman to officially observe at the Palomar Observatory, which was home to the worlds largest telescope. Before her death in 2016, Rubin served as a mentor to other women astronomers and fought for better gender parity in astronomy.

Rubin observed the universe with some of the largest telescopes available during the late twentieth century, including those in Chile, at the newly established Cerro Tololo Inter-American Observatory and the Las Campanas Observatory. When Rubin began her astronomical career, Chile held a small fraction of the worlds telescopes. However, largely due to the nearly perfect dry and clear conditions, particularly in the Atacama Desert in Chiles northern region, today Chile contains the vast majority, around 70%, of the worlds large ground-based telescopes.

Most Chilean observatories constructed in the last 60 years are operated by North American and European nations. For their access to Chiles pristine skies, these international collaborators agreed to reserve 10% of observing time for Chilean astronomers, a percentage that many argue is not adequate. The number of Chilean universities offering PhD degrees in astronomy has increased in the last decade and the number of professional astronomers working in Chile has tripled in that decade alone. At the Vera C. Rubin Observatory, all of the data will be made available to both Chilean and U.S astronomers which should aid the growing number of astronomers in Chile. However, in Chile, women astronomers still only account for 15% of the countrys astronomers, which is about half their representation worldwide. Placing Rubins name on a new observatory and providing greater access to its data is a recognition of her incredible accomplishments and tireless efforts but it is also a reminder of the continued marginalization of women in astronomy and the further inequity across race and nationality.

While the number of women astronomers in Chile remains low, women have succeeded in contributing to the extension of our knowledge of the universe. Dr. Mara Teresa Ruiz broke through her own barriers as she worked to become a trailblazer for women in Chilean astronomy. Born in Santiago, Ruiz was the first woman to earn a degree in the newly formed astronomy program at the University of Chile. When she graduated there were no astronomy PhD granting programs in Chile so she traveled to the United States where she attended Princeton University, the same institution where two decades earlier, Rubin had not been permitted to apply. In 1975, Ruiz became the first woman to earn a PhD in astrophysics at Princeton. Ruiz eventually returned to Chile and helped to rebuild and foster the university system. In 1997, she discovered one of the first free floating brown dwarfs using the European Southern Observatorys La Silla observatory. Brown dwarfs are star-like objects that are too small to fuse hydrogen but too large to be planets. Their discovery and subsequent study refuted the hypothesis that brown dwarfs may account for a significant amount of the dark matter in the universe. For her long and accomplished career in astronomy, Ruiz was awarded Chiles National Prize for Exact Sciences and remains a leader for science in Chile.

Ruiz paved the way for younger scientists to follow in her footsteps. Dr. Brbara Rojas-Ayala began her astronomical studies under Ruiz and continues to research dwarf stars at the University of Tarapac. Dr. Maritza Soto has already impressed with the discovery of three planets, the first of which she discovered in 2011 while a graduate student at the University of Chile. Soto continues her research while hoping to normalize careers in astronomy, particularly for women. In 2019, Soto hoped to import that astronomy is not alien stuff that only two people in the world do; its really a career path. Its something you can do, that anyone can do, if you work a lot for it. Its not impossible, you dont have to be a genius, she says. You can just be a normal person.

By the time the Vera Rubin Observatory begins operations in 2022, followed by other large telescopes built along the Chilean Andes, we can hope that the number of women astronomers using those facilities will continue to rise. To accomplish this, major steps still need to be taken and enforced to make the astronomy community more inviting and more supportive of women, particularly in the places that host the worlds telescopes.

Link:

The Vera C. Rubin Observatory and Women of Chilean Astronomy - National Air and Space Museum

It is no exaggeration to say that the study of extrasolar planets has exploded in recent decades. To date, 4,375 exoplanets have been confirmed in 3,247 systems, with another 5,856 candidates awaiting confirmation. In recent years, exoplanet studies have started to transition from the process of discovery to one of characterization. This process is expected to accelerate once next-generation telescopes become operational.

As a result, astrobiologists are working to create comprehensive lists of potential biosignatures, which refers to chemical compounds and processes that are associated with life (oxygen, carbon dioxide, water, etc.) But according to new research by a team from the Massachusetts Institute of Technology (MIT), another potential biosignature we should be on the lookout for is a hydrocarbon called isoprene (C5H8).

The study that describes their findings, Assessment of Isoprene as a Possible Biosignature Gas in Exoplanets with Anoxic Atmospheres, recently appeared online and has been accepted for publication by the journal Astrobiology. For the sake of their study, the MIT team looked at the growing list of possible biosignatures that astronomers will be on the lookout for in the coming years.

To date, the vast majority of exoplanets have been detected and confirmed using indirect methods. For the most part, astronomers have relied on the Transit Method (Transit Photometry) and the Radial Velocity Method (Doppler Spectroscopy), alone or in combination. Only a few have been detectable using Direct Imaging, which makes it very difficult to characterize exoplanet atmospheres and surfaces.

Only on rare occasions have astronomers been able to obtain spectra that allowed them to determine the chemical composition of that planets atmosphere. This was either the result of light passing through an exoplanets atmosphere as it transitted in front of its star or in the few cases where Direct Imaging occurred and light reflected from the exoplanets atmosphere could be studied.

Much of this has had to do with the limits of our current telescopes, which do not have the necessary resolution to observe smaller, rocky planets that orbit closer to their star. Astronomers and astrobiologists believe that it is these planets that are most likely to be potentially habitable, but any light reflected from their surfaces and atmospheres is overpowered by the light coming from their stars.

However, that will change soon as next-generation instruments like the James Webb Space Telescope (JWST) takes to space. Sara Seager, the Class of 1941 Professor of Physics and Planetary Sciences at MIT, leads the research group responsible (aka. the Seager Group) and was a co-author on the paper. As she told Universe Today via email:

With the upcoming October 2021 launch of the James Webb Space Telescope wewillhave our first capability of searching for biosignature gasesbut it will be tough because the atmospheric signals of small rocky planet are so weakto begin with. With the JWST on thehorizon the number of people working in thefield has growntremendously.Studies such as this one coming up with newpotential biosignature gases, and other workshowing potential false positives even for gases such as oxygen.

Once it is deployed and operational, the JWST will be able to observe our Universe at longer wavelengths (in the near- and mid-infrared range) and with greatly improved sensitivity. The telescope will also rely on a series of spectrographs to obtain composition data, as well as coronagraphs to block out the obscuring light of parent stars. This technology will enable astronomers to characterize the atmospheres of smaller rocky planets.

In turn, this data will allow scientists to place much tighter constraints on an exoplanets habitability and could even lead to the detection of known (and/or potential) biosignatures. As noted, these biosignatures include the chemical indications associated with life and biological process, not to mention the types of conditions that are favorable to it.

These include oxygen gas (O2), which is essential to most forms of life on Earth and is produced by photosynthetic organisms (plants, trees, cyanobacteria, etc.). These same organisms metabolize carbon dioxide (CO2), which oxygen-metabolizing life emits as a waste product. Theres also water (H2O), which is essential to all life as we know it, and methane (CH4), which is emitted by decaying organic matter.

Since volcanic activity is believed to play an important role in planetary habitability, the chemical byproducts associated with volcanism hydrogen sulfide (H2S), sulfur dioxide (SO2), carbon monoxide (CO), hydrogen gas (H2), etc. are also considered biosignatures. To this list, Zhan, Seager, and their colleagues wished to add another possible biosignature isoprene. As Zhan explained to Universe Today via email:

Our research group at MIT focuses on using a holistic approach to explore all possible gases as potential biosignature gas. Our prior work led to the creation of the all small molecules database. We proceed to filter the ASM database to identify the most plausible biosignature gas candidates, one of which is isoprene, using machine learning and data-driven approaches Dr. Zhuchang Zhan.

Like its cousin methane, isoprene is an organic hydrocarbon molecule that is produced as a secondary metabolite by various species here on Earth. In addition to deciduous trees, isoprene is also produced by a diverse array of evolutionary-distant organisms such as bacteria, plants, and animals. As Seager explained, this makes it promising as a potential biosignature:

Isoprene is promising because it is produced in vastqualities by life on Earthas much as methane production!Furthermore, a hugevariety of life forms (from bacteria to plants and animals), those that are evolutionary distant from each other, produce isoprene, suggesting it might be some kind of keybuilding block that life elsewhere might also make.

While isoprene is about as abundant as methane here on Earth, isoprene is destroyed by interaction with oxygen and oxygen-containing radicals. For this reason, Zhang, Seager, and their team chose to focus on anoxic atmospheres. These are environments that are predominantly composed of H2, CO2, and nitrogen gas (N2), which is similar to what Earths primordial atmosphere was composed of.

According to their findings, a primordial planet (where life is beginning to emerge) would have abundant isoprene in its atmosphere. This would have been the case on Earth between 4 and 2.5 billion years ago when single-celled organisms were the only life and photosynthetic cyanobacteria were slowly converting Earths atmosphere into one that was oxygen-rich.

By 2.5 billion years ago, this culminated in the Great Oxygenation Event (GOE), which proved toxic to many organisms (and metabolites like isoprene). It was also during this time that complex lifeforms (eukaryotes and multi-celled organisms) began to emerge. In this respect, isoprene could be used to characterize planets that are in the midst of a major evolutionary shift and laying the groundwork for future animal phyla.

But as Zhang noted, teasing out this potential biosignature will be a challenge, even for the JWST:

The caveats with isoprene as a biomarker are that: 1. 10x-100x the Earths Isoprene production rate is needed for detection; 2. Detecting Near-Infrared isoprene spectral feature can be hindered by the presence of methane or other hydrocarbons. Unique detection of isoprene will be challenging with JWST, as many hydrocarbon molecules share similar spectra features in Near-Infrared wavelengths. But future telescopes that focus on the mid-IR wavelength will be able to detect isoprene spectral features uniquely.

Beyond the JWST, the Nancy Grace Roman Space Telescope (successor to the Hubble mission) will also be taking to space by 2025. This observatory will have the power of One-Hundred Hubbles and its recently-upgraded infrared filters will allow it to characterize exoplanets on its own and through collaborations with the JWST and other great observatories.

There are also several ground-based telescopes currently being built here on Earth that will rely on sophisticated spectrometers, coronographs, and adaptive optics (AOs). These include the Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), the Thirty Meter Telescope (TMT) These telescopes will also be able to conduct Direct Imaging studies of exoplanets, and the results are expected to be ground-breaking.

Between improved instruments, rapidly improving data analysis and techniques, and improvements in our methodology, the study of exoplanets is only expected to accelerate further. In addition to having tens of thousands of more available for study (many of which will be rocky and Earth-like), the unprecedented views we will have of them will let us see just how many habitable worlds are out there.

Whether or not this will result in the discovery of extraterrestrial life within our lifetimes remains to be seen. But one thing is clear. In the coming years, when astronomers start combing through all the new data they will have on exoplanet atmospheres, they will have a comprehensive list of biosignatures to guide them.

Seager and Zhans previous work include a concept for a Martian greenhouse that could provide all the necessary food for a crew of four astronauts for up to two years. This greenhouse, known as the Biosphere Engineered Architecture for Viable Extraterrestrial Residence (BEAVER), took second place in the 2019 NASA BIG Idea Challenge. You can read more about it here.

Further Reading: arXiv

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If Astronomers see Isoprene in the Atmosphere of an Alien World, Theres a Good Chance Theres Life There - Universe Today

Galaxy clusters are the largest structures in the universe bound together by gravity. They can contain thousands of galaxies, enormous oceans of hot gas, invisible islands of dark matter and sometimes the glowing ghost of a jellyfish or two.

In the galaxy cluster Abell 2877, located in the southern sky about 300 million light-years from Earth, astronomers have discovered one such jellyfish. Visible only in a narrow band of radio light, the cosmic jelly is more than 1 million light-years wide and includes a large lobe of supercharged plasma, dripping with tentacles of hot gas.

The structure's jelly-like appearance is both "ghostly" and "uncanny," according to the authors of a new paper published March 17 in the Astrophysical Journal. However, even more astonishing than the space jelly's shape is how quickly the structure vanishes from view, the authors said.

Related: 12 Trippy objects hidden in the Zodiac

"This radio jellyfish holds a world record of sorts," lead study author Torrance Hodgson, of the International Centre for Radio Astronomy Research (ICRAR) in Perth, Australia, said in a statement. "Whilst it's bright at regular FM radio frequencies, at 200 megahertz the emission all but disappears. No other extragalactic emission like this has been observed to disappear anywhere near so rapidly."

The universe is swimming with energetic structures that are only visible in radio wavelengths, like the mysterious X-shaped galaxies cartwheeling through space, or the twin blobs at the center of the Milky Way. However, no structure this large has ever been observed in such a narrow band of the radio spectrum.

According to the researchers, that likely means this cosmic jellyfish is actually an odd bird known as a "radio phoenix."

Like the mythical bird that died in flame and rose again from the ashes, a radio phoenix is a cosmic structure that's born from a high-energy explosion (like a black hole outburst), fades over millions of years as the structure expands and its electrons lose energy, then finally gets reenergized by another cosmic cataclysm (such as the collision of two galaxies).

To create a radio phoenix, that last cosmic event must be powerful enough to send shockwaves surging through the dormant cloud of electrons, causing the cloud to compress and the electrons to spark with energy again. According to the study authors, that could cause a structure like the jellyfish cluster to glow brightly in certain radio wavelengths, but dim rapidly in others.

"Our working theory is that around 2 billion years ago, a handful of supermassive black holes from multiple galaxies spewed out powerful jets of plasma," Hodgson said.

That plasma's energy faded over millions of years, until "quite recently, two things happened the plasma started mixing at the same time as very gentle shock waves passed through the system," Hodgson said. "This has briefly reignited the plasma, lighting up the jellyfish and its tentacles for us to see."

The researchers used a computer simulation to show that this explanation is a plausible origin story for that big jellyfish in the sky, though several big questions such as where the "gentle shockwaves" came from remain unanswered. The team hopes to take a closer look at the jellyfish in the future, following the completion of the Square Kilometre Array a network of hundreds of radio telescope antennas planned for construction in the Australian Outback.

Originally published on Live Science.

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Astronomers see a ghostly 'radio jellyfish' rise from the dead in the southern sky - Livescience.com

Two years ago, astronomers managed to photograph a black hole for the very first time. The team behind theEvent Horizon Telescopeproject was awarded the Breakthrough Prizeknown as the Oscars of sciencefor their effort, and New Yorks Museum of Modern Art acquired the image in the form of an inkjet print.

Now, the same astronomers have captured the most detailed photograph to date of a black hole, one of the universes most enigmatic features, which was once thought to be unobservable.

Seen in polarized light, the fuzzy ring of light in the original image is now in focus, with crisp lines swirling in toward the center of what appears to be a bottomless pit, sucking in anything and everything within its grasp.

Its like putting on a pair of polarized sunglasses on a bright sunny dayall of a sudden you can see whats going on, astronomer Sheperd Doeleman of the Harvard-Smithsonian Center for Astrophysics told the New York Times.

The Event Horizon Telescope was designed to capture images of a black hole. The image shows the light around the black holes boundary. Image courtesy of the Event Horizon Telescope.

A black hole is a field of matter so dense that not even rays of light can escape its gravitational pull. But as the black hole inexorably draws in gas, dust, and stars, some light is actually propelled outward in jets of energetic particles.

This jet process is totally amazingsomething the size of our solar system can shoot out a jet that pierces through entire galaxies and even galaxy neighborhoods, Event Horizon Telescope team member Sara Issaoun told IGN.

The new image shows the black holes vortex, and the magnetic field lines at its inner edge, illustrating how the magnetic field both feeds the black holes insatiable hunger and powers the intergalactic fireworks show that surrounds it.

This image shows the jet in the M87 galaxy in polarized light. It is 6,000 light-years long. Image courtesy of ALMA (ESO/NAOJ/NRAO), Goddi et al.

The main finding is that we not only see the magnetic fields near the black hole as expected, but they also appear to be strong. Our results indicate that the magnetic fields can push the gas around and resist being stretched. The result is an interesting clue to how black holes feed on gas and grow,Jason Dexter, a professor at the University of Colorado Boulder, told Space.com.

We are now seeing the next crucial piece of evidence to understand how magnetic fields behave around black holes, and how activity in this very compact region of space can drive powerful jets that extend far beyond the galaxy, said Monika Mocibrodzka, coordinator of the EHT Polarimetry Working Group, in a statement.

The galaxy Messier 87, in the constellation Virgo, as capture by the European Southern Observatorys Very Large Telescope. Photo courtesy of the European Southern Observatory.

The findings from the new image are the subject of three papers published last week in the Astrophysical Journal Letters, two by the Event Horizon Telescope Collaboration and one by lead author Ciriaco Goddi of Radboud University in the Netherlands.

This black hole captured by the telescope lies 55 million light-years away, at the heart Messier 87, a supergiant elliptical galaxy in the constellation Virgo.At 6.5 billion times bigger than our sun, it is unimaginably supermassivethe surrounding circular field of electrified gas or plasma captured in the image measures about 30 billion miles across, or four times Plutos orbit.

The Atacama Large Millimeter/submillimeter Array (ALMA), part of the Event Horizon Telescope Collaboration, set against the Milky Way. Photo by European Southern Observatory Photo Ambassador Babak Tafreshi.

Capturing the image was a global effort. TheEvent Horizon Telescope collaboration is powered by eight ground-based radio telescopes in Chile, Mexico, Spain, Hawaii, Arizona, and the Antarctic, overseen by an international team of radio astronomers thatsynchronize their observations by atomic clock. Together, the sites essentially create a planet-sized telescope.

The projects name comes from the point of no return around a black hole. Beyond the event horizon, no light or matter can escape.

Watch a video approaching the Messier 87 galaxy black hole below.

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Astronomers Have Captured the Most Detailed Photo of a Black Hole EverSee the Magnetic Fields That Power It Here - artnet News

One of the biggest problems is astronomy is a simple one: Not enough light. One of the reasons we make telescopes so big is to collect light to see faint things. The analogy is like a bucket in rain: The wider the bucket the more rain you collect. Photons fall from the sky, and the bigger your mirror the more light you collect.

It's hard to make big telescopes. Supporting a mirror bigger than 8 meters is hard, though making them segmented (like the James Webb Space Telescope) helps. Still, the cost is huge, and to make scopes bigger than what we have now you have to start thinking in the billions of dollars. Ouch.

So astronomers get clever in ways to collect light. One of the most clever astronomers I know is David Kipping. I've written about his work a few times, including about his search for exomoons. Like so many others, he's a photon-starved astronomer, and he recently published an amazing concept to collect more light from cosmic objects: The Terrascope.

It's called that because it uses the Earth as a gigantic lens to focus light.

Yes, seriously. It's the Whole Earth Telescope.

He made a video explaining it:

A lens bends the path light takes (this is called refraction), so that a photon that would otherwise miss your camera gets directed into it. Again with a rain analogy: A raindrop that falls a meter away from you misses you, but if you could deflect (refract!) the path of that drop a little bit while it's still up high, it'll be aimed right at you, and you get wet.

In the case of the Terrascope, the lens is actually Earth's atmosphere. When light moves from one medium to another (like air to water, or space to air), its path bends a little bit. The amount it bends depends on the angle it enters and the stuff (what we usually call the medium) it's passing through. This is why the Sun (and Moon) looks flattened when it sets; the top part of the Sun is passing through less air than the bottom part, and in effect the light from those parts of the Sun get squeezed together, making the Sun look smaller vertically.

So a beam of light coming from a distant star, say, passes through Earth's air and its path bends. The most it bends is about a degree (twice the size of the Sun or Moon in the sky). Now imagine you're floating in space, with the Earth between you and that star. You can't see the star because the Earth is in the way. BUT if you are at just the right distance, the Earth's air will bend the light of the star right at you. The distance from Earth you need to be for this is about 360,000 kilometers, nearly all the way to the Moon.

Now think about this: From there, the Earth looks like a disk, and the air around it a thin ring. Any photon from that star hitting Earth's air at any point in that ring will get bent toward you. All those photons would miss you otherwise, but with Earth's air bending them you see lots of photons. That's exactly how a lens works.

I'll note that the header image of his Twitter account is a fanciful drawing of how this works.

This same effect also creates a phenomenon called a central flash, when an object with an atmosphere passes directly in front of a much more distant object and you get a sudden brightening of light when this eclipse (really, called an occultation) is at its midpoint. It's exactly the same effect I'm talking about here. It's been seen with Neptune's moon Triton blocking a distant star, as well as with Saturn's moon Titan doing the same thing.

So faint stars will appear much brighter because of the extra photons. The light amplification can be huge: For a one-meter telescope, it can be as much as a factor of 80,000! That's incredible. That's 10.5 magnitudes, for those who know their astronomy. A telescope like that could see objects down to Hubble-like faintness even better than Hubble.

It turns out there's a lot of physics involved here, which I've elided over. For example, the air above the Earth gets less dense (and in general colder) with height, and that affects refraction. It depends on the wavelength of light you're looking at as well. And placing a one-meter telescope that far from Earth has other issues, too. The Moon will get close enough that you'll have to do a lot of station keeping every month, for one. Clouds in Earth's atmosphere block light, which is kind of a pain, too, which greatly reduces the light you can see.

Also, you can only look at whatever is behind the Earth, so either you just look at stuff in the sky that happens to be there (and that changes all the time, repeating once a year as the Earth orbits the Sun) or you'll have to move your telescope a loooong way. Kipping goes into some of those problems in his paper.

He finds that a lot of these issues can be overcome simply by moving the telescope farther out. Put it about 1.5 million kilometers from the Earth, and the light that passes about 14 km above Earth's surface gets bent into focus. That avoids clouds, which is great, and most infrared light can pass through the air at that height, allowing that part of the spectrum to be observed as well.

At that distance, a one-meter telescope has the equivalent collecting power of a 150meter telescope! Yegads. That's a lot of light, and the more light you collect from an object the better your data are. Which reminds me: You'll have to block the very bright Earth from your detector as well, but that's something we know how to do (using a coronagraph), and is likely just an engineering problem.

Is a Terrascope actually possible? Well, even Kipping is skeptical in his video and by that I don't mean cynical, I mean scientifically skeptical, being careful to acknowledge the plusses and minuses of the concept. He notes there's a long way to go to figure out all the problems here, but it's very much worth proposing this idea to the community and seeing what happens. And if it does work, it'll be the coolest telescope flying.

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Terrascope: The Whole Earth Telescope - SYFY WIRE

Earths only natural satellite, The Moon, is by far the most romantic and inspiring celestial object in our Solar System. Since the beginning of time, adults and children indistinctively have been lifting their eyes to the sky to gaze at this magnificent celestial body in awe and amazedness.

For millennia, The Moon has sparked the imagination of writers and poets, including James Joyce (What counsel has the hooded moon, Put in thy heart, my shyly sweet, Of Love in ancient plenilune, Glory and stars beneath his feet) or Shakespeare ("th'inconstant moon, That monthly changes in her circled orb"), among many others.

In music, the Moon has captivated the spirit of great artists like The Rolling Stones (Moon Is Up), Pink Floyd (The Dark Side Of the Moon), The Beatles (Mr Moonlight) and The Police (Walking on the Moon). Neil Young, the authors favourite, sings a tribute to his wife, picturing the couple dancing under an Harvest Moon, the closest full Moon to the autumn equinox.

And what better representation than art? For centuries, The Moon has played a central role on the canvases of great painters such as Michelangelo (Creation of the Sun, Moon, and Plants), Edvard Munch (Moon Light), Vincent Van Gogh (White House at Night) and Henri Rousseau (La Encantadora de Serpientes).

But our natural satellite is not only a muse for artists and poets. At an average distance of 384,400 km (238,855 miles), The Moon has a strong impact on our planet. It moderates Earths motion on its axis, which stabilises the climate thus making life possible and favouring agriculture. It also regulates the tides to a rhythm that certain species of crabs, worms and fishes follow for their reproduction.

Sadly, The Moon is constantly shifting away from us at a rate of approximately 3.8 cm (1.5 in) each year, similar to the rate our fingernails grow. But no fear, it will take billions of years before the effects become noticeable.

From Earth, we only see one face of The Moon. This phenomena is called tidal locking, and means that The Moon rotates on its own axis at the same rate that it orbits Earth thus showing us always the same face. A complete orbit around Earth takes 27 days but due to our motion and orbit around the Sun, from our perspective the Moon appears to orbit us every 29 days.

The surface of The Moon is marked by long-inactive volcanoes, impact craters, and lava flows. The areas of the surface that appear bright are called Highlands whereas the dark features are called Marea (from Latin mare: sea). The latter are impact basins that were filled with lava from the volcanoes between 4.2 and 1.5 billion years ago. Some of the Mareas are so marked that are easily visible to the naked eye.

The surface temperature can reach peaks of approximately 130C (265F) when lit by the Sun, then dropping to -170C ( -274F) in darkness. Initial samples returned to Earth from the Apollo missions did not detect any signs of liquid water. In 2008, however, the Indian mission Chandrayaan-1 detected hydroxyl molecules spread across the lunar surface and concentrated at the poles.

Following missions went even further and proved that the surface presents high concentrations of ice water in the permanently shadowed regions of the lunar poles. Finally, in October 2020 NASA confirmed for the first time to have found water also on the sunlit surface of the Moon.

This discovery is of significant importance as it makes the Moon a little more hospitable and simplifies life for NASAs scientists in view of the establishment of a stable colony on our satellite, but also for future missions such as the Artemis Program, which will land the next man and the first woman on the Moon by 2024.

Among other things, the mission will serve as an experiment before sending astronauts to Mars. As a great man once said: That's one small step for a man, one giant leap for mankind.

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Astronomy: The Moon, the most romantic object in the sky - RTL Today

The Deep Space Climate Observatory (DSCOVR) captured a view of the moon as it passed between the spacecraft and Earth. DSCOVR EPIC team

The moon orbits Earth - right? The answer is actually a little more complicated than that.

The moon is circling a point about 3,000 miles from our planet's center, just below its surface. Earth is wobbling around that point, too, making its own circles.

That spot is the Earth-moon system's center of mass, known as the barycenter. It's the point of an object (or system of them) at which it can be balanced perfectly, with the mass distributed evenly on all sides.

The Earth-moon barycenter doesn't line up exactly with our planet's center. Instead, it's "always just below Earth's surface," as James O'Donoghue, a planetary scientist at the Japanese space agency (JAXA), explained on Twitter.

It's hard to imagine what that looks like without seeing it for yourself. So O'Donoghue made an animation to demonstrate what's going on. It shows how Earth and the moon will move over the next three years.

The distance between Earth and the moon is not to scale in the animation, but O'Donoghue used NASA data, so the positions over time are accurate.

"You can pause the animation on the present date to figure out where the Earth and moon physically are right now," O'Donoghue said.

Every planetary system - including the star or planet that appears to be at the center - orbits an invisible point like this one. Our solar system's barycenter is sometimes inside the sun, sometimes outside of it. Barycenters can help astronomers find hidden planets circling other stars: A star's wobbling motion allows scientists to calculate mass they can't see in a given system.

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O'Donoghue made a similar animation of Pluto and its moon, Charon. In this system, the barycenter is always outside of Pluto.

That's because Charon's mass is not that much smaller than Pluto's, so the system's mass is more evenly distributed than Earth and our moon.

Because the barycenter is outside of Pluto, O'Donoghue said, you could actually consider this to be a "double (dwarf-)planet system" rather than a dwarf planet and its moon.

In his free time, O'Donoghue has also made animations to explain why leap years are necessary, why you've probably never seen a model of the solar system to scale, and how incredibly slow the speed of light is.

Read the original article on Business Insider

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An astronomer's animation shows how Earth and the moon both orbit a spot 3,000 miles from the true center of the planet - Yahoo News