Category Archives: Astronomy

Move over, Gustav Holst. Theres a new Planets in town. And this one is based on astronomy, not astrology.

Holsts seven-movement orchestral suite The Planets premiered in London in 1918. Now, a little more than a century later, a modern version on the theme saw first light on Sunday May 22, 2022. But while Holst turned to astrology for inspiration, composer Daniel Perttu turned to astronomy.

Pianist Jeffrey Biegels longtime dream was to bring to life an updated version of Holsts The Planets, infusing the music with current scientific understanding. Biegel was born deaf, and until the age of three, when corrective surgery allowed him to hear for the first time, his world was very closed. He relied on other means of expression and communication, and so music became his first language. As a result, his projects often have an out of the box element. Biegels vision of a revamped Planets features the pianist as a space traveler journeying through the solar system.

A Planets Odyssey isnt your typical three-movement concerto. Instead, its in a theme-and-variations form. It begins with the Big Bang, followed by the pianist introducing the main theme of the concerto, Perttu explains. This theme is then varied as the pianist visits each planet and is inspired by the unique properties of each planet. Like Holst, Perttu skips the Earth. But unlike Holst, these planets are featured in their order from the Sun. And more importantly, Perttu focuses solely on the science.

Perttu picked a few characteristics of each planet for inspiration and transformed those into sonic visions. For example, Mercury, subject of the first variation, is the innermost and smallest of the solar systems planets and experiences extremes in temperature. It also has virtually no atmosphere. So Perttu drew on those characteristics to produce a variation that conveys the imagery of a stark, extreme kind of place.

Venus is the brightest object in the night sky, apart from the Moon and the Sun. Its atmosphere is largely roiling clouds of carbon dioxide. At the planets surface, where temperatures reach a whopping 470C (870F), the pressure is some 90 times that of Earths. At some point in its early, cooler history, Venus may have had a shallow liquid-water ocean and may have harbored life, but thats all long gone by now. The prospect of potential current or past life is always thrilling, and thats the angle that sonically describes Venus in this variation.

Rounding out the rocky planets, Mars continues to capture our imagination, with its dusty red surface and the solar systems biggest volcano. Perttu nevertheless reads a sadness in Marss story. A planet that once may have had a lush environment with liquid water on its surface and perhaps life is today instead a cold and arid world.

When we get to the gas giants, Perttu introduces a sense of airiness to the music. First comes majestic Jupiter, the largest planet in the solar system, rich in hydrogen and helium. Its famous for its Great Red Spot, which is, in fact, one humongous storm that has raged for more than 300 years. The Great Red Spot and other storms on Jupiter are also sites of lightning! In fact, Perttu describes this passage as swirly, blustery, and sometimes tempestuous.

Ask most any astronomer what drew them to the subject, and the answer more often than not is their first view of Saturn through a telescope. The sight of the ethereal planet with its system of rings is inspiring at every level. But to add to the planets attraction, we now know that its atmosphere contains diamonds. And not only that, but that the diamonds might fall as rain! Hence, Saturns variation is slower but shimmery in its sensibility.

William Herschel discovered Uranus in 1781. The ice giants atmosphere is largely hydrogen and helium, with traces of methane that give the planet its eerie, greenish hue (by absorbing the red wavelengths of light). Uranus is a planet with a quirk: A cataclysmic interaction with another body in the early solar system tipped it over on its side with respect to its orbital plane, so instead of orbiting the Sun like the other planets, it rolls along in its orbit. Because of this, Perttu has inverted the main theme in the variation, as well as infusing it with a dark, dismal sentiment.

Perttu composed the eighth variation to reflect a sense of windiness since the last of our planets, Neptune, is the windiest of them all. The blue ice giant, the most distant of all planets (more than 30 times the Earth-Sun distance), is dark and cold, and supersonic winds rage through its atmosphere at speeds greater than 2,000 km/h (1,200 mph). For comparison, the fastest winds recorded on Earth clock in at around 400 km/h.

And in a neat final touch, we end our odyssey all the way out in the Kuiper Belt. Of course, when Holst composed The Planets, Pluto and other distant solar system objects hadnt yet been discovered. But in a fitting coda to A Planets Odyssey, Perttu brings us to the very outer edges of our solar system.

On Sunday May 22, 2022, in the evening, the Canton Symphony Orchestra (lead commissioning orchestra in a consortium of multiple orchestras) ushered A Planets Odyssey into the world, under the direction of the Orchestras Music Director, Gerhardt Zimmermann. Biegel was at the piano.

Today is tomorrow's history, Biegel said, after the concert. There is a unique energy in the room when all the stars align to witness the birth of a new creation Dan's A Planets Odyssey created a synergy of musical, spiritual, and scientific energies igniting the hearts and minds of the audience and the performers. He concludes, It is a feeling which joins us in an historic moment like no other.

Perttu was also philosophical following the concert. Writing this piece was not only about creating a musical representation of our scientific knowledge of the planets in 2020, but it was also about how the science can inspire imagination, he mused. Who would have thought of diamond rain?! There are mysteries in this universe that likely go beyond our most fantastical speculation and this piece is meant to capture that spirit as well.

After the thrill of Sunday evening, Biegel notes that the journey doesnt finish there. He envisions that A Planets Odyssey will serve the purposes of music, science and education for students learning about our solar system.

If youre in the Flagstaff, Arizona, area in September 2022, make sure you catch the next performance of A Planets Odyssey by the Flagstaff Symphony Orchestra conducted by Music Director Charles Latshaw, with Jeffrey Biegel as piano soloist.

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Piano Concerto on the Planets Premieres - Sky & Telescope - Sky & Telescope

By Minerva Baumann, Media Relations OfficerNMSU News Team

Astronomers cant go back in time to observe how the solar system was formed, but they can observe planets that are forming now and use computer simulations to help them better understand the process.

A New Mexico State University astronomy professor is part of a team of scientists that wrote a paper published this month in the journal Nature that has identified a protoplanet in another star system that may be forming differently than expected. It is the first system in which the evidence points to this alternative theory of planet formation.

The paper images of embedded Jovian planet formation at a wide separation around AB Aurigae was published in the May 9 edition of the journal Nature and co-authored by NMSU astronomy associate professor Wladimir Lyra.

The ultimate arbiter of science is nature. We need to observe what nature does. Then to advance our knowledge, we build models to explain our observations, said Lyra, who builds computer models based on astronomical data.

The recent paper is a result of Lyras collaboration among a group of scientists including lead author Thayne Currie, an astrophysicist at NASA-Ames Research Center and the Subaru Telescope. Currie, along with other researchers, shared observational data of the protoplanet forming around AB Aurigae, a very young star in the Auriga constellation about 531 light years from the Sun.

Its not even a baby planet. Its an embryo planet, Lyra said. Its a planet that is still embedded in the disc. These planets form from gas and dust around young stars. Thats how the Earth and other planets around the Sun were formed.

Using the Subaru Telescope and the Hubble Space Telescope, researchers found the data on this protoplanet was intriguing and not easily explainable. Lyra created a computer simulation to match the observations and better understand the process of how this massive gas giant planet is forming.

What they found is unexpected.

On this particular observation, what was observed was a planet 10 times more massive than Jupiter at a distance from the star that is twice the distance that Pluto is from the sun, Lyra said. This planet is still embedded in the disc. It is also still very hot. You can see the object is still glowing from its formation.

For decades, scientists have relied on two theories of how planets and stars form. One is core accretion, also known as bottom up, when small bodies about the size of an asteroid, collide and coalesce in a disk cloud, eventually adding gasses and growing massive planets the size of Jupiter or Saturn.

The second theory of planet formation is gravitational instability, also known as top down. This theory begins with a massive disc of dust and gas so large that it ends up fragmenting. In a disc around a star, these fragments collapse from the top down and are about as massive as Jupiter. This is the process by which massive stars form in a galaxy.

While the theory of gravitational instability forming planets has been around for decades, there has been no clear-cut case that demonstrates a planet could be formed in that way. The Nature article outlines evidence that the protoplanet observed around AB Aurigae is such a planet, countering long established theories.

I think that the main message from a theoretical perspective from this paper is that this is a system for which gravitational instability is a plausible mechanism for formation of this protoplanet, Lyra said. There are several independent lines of evidence that point toward gravitational instability.

Lyra emphasized while the evidence points to the formation of this protoplanet by gravitational instability, so far it doesnt disprove the possibility of it forming through the core accretion method.

The team will continue looking at that system in longer wavelengths, probing deeper into the disc. Lyra called it a very interesting avenue to explore in the future to see if there are conditions that this planet can still form by core accretion.

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NMSU professor has alternate theory on planet formation - Las Cruces Bulletin

I believe that it is in our DNA that there is the need to explore, to find something and make sense to it.

The connection between space and our origins is unique and quite identical, so I believe that through my images of the cosmos, Im reconnecting to that realm that I belong.

As much as I love photographing space as an explorer, the images that I capture are much more prefunding as Im witnessing the grandeur with never ending bliss of heaven.

Astrophotography makes me feel like actually taking part in that whole thing of whats going on.

The fact that we cant explain the wonders of the cosmos and the Universe, drives me to go out more over and over again.

The Milky-way is our home in the cosmos, the galaxy that we live in holds about 100 billion stars. During the past few decades we have discovered that at least from a physical perspective, humans are but a speck of dust in the grand scheme of the universe.We live on a small planet which revolves around a very ordinary star.

The Kepler space observatory has shown us that our Milky Way galaxy is teeming with about a billion Earth-size planets orbiting their parent stars in the Habitable Zone (that not-so-cold-not-so-hot region that allows for liquid water to exist on the planets surface) so its inevitable that earth like planets exist in our home galaxy, one can imagine now what cannot exist in the grandeur cosmos.

A deep image of a tiny piece of sky, taken with the Hubble Space Telescope. Almost every point of light in this image represents a galaxy with about a hundred billion stars like the Sun.

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Why am I addicted to astronomy? - Newsbook

Astronomers have discovered a new example of a creepy kind of dead star that shoots death rays so powerful they cook their binary companion star and eat its remains.

No, Im not kidding. And this discovery is interesting because the two stars are closer together than any other object in its class, swinging around each other in an astonishing 62 minutes. This makes it a weird example of whats a weird class of objects in the first place.

To look for such objects, a team of astronomers used archived observations from the Zwicky Transient Facility a sky survey that takes huge images of the sky every night looking for things that move or change brightness: Asteroids, supernovae, variable stars, black holes with bad table manners, and the like.

They searched the data for short-timescale periodic brightness changes in 20 million objects that were fainter than youd expect for a star of their kind. That may seem pretty specific, but then they had a specific kind of object in mind: black widow pulsars.

Thats an apt name for something that, well, shoots out a death ray, cooks its companion, and eats it.

Ive written about pulsars many times:

Pulsars are neutron stars,the incredibly dense corpse of the core of a massive star that exploded as a supernova. The outer layers of the star get blasted away, but the core itself collapses. If the core has less than about three times the Suns mass it will become a ball of neutronsvery roughly 20 kilometers wide. This makes it ultradense; a cubic centimeter of it the size of a six-sided die will have a mass of about 100 million tons,about the same as if you took every car in the United States and crushed them down until all together they were the size of a sugar cube.

Neutron stars tend to spin rapidly, and have powerful magnetic fields that can be trillions of times stronger than Earths. This sets up a lot of different phenomena; one is that this powers incredibly strong beams of radiation that blast away from the magnetic poles of the star, which sweep around the sky due to the neutron stars rotation like a pair of lighthouse beams.When these beams pass over Earth we see a blip of light, a pulse, hence the termpulsar.

Some pulsars are solitary, and others have normal stars like the Sun orbiting them. Its not a lot of fun being near a pulsar, but if youre a star far enough away you can survive, even in a binary system.

But some stars are much closer in and face the fury of hell.

A star that close is more likely to be hit by those spinning beams of radiation, and also the beams effects on them are more powerful. They can zap the binary companion star so energetically that it heats up and loses material the pulsar is almost literally boiling it away. That material then leaves the star and flies into space where some will fall onto the pulsar, feeding the energy and the beams.

Again, black widow pulsar is amazingly apt.

So thats what the astronomers were looking for in the data, and not only did they find one, they found a weird one. Called ZTF J1406+1222, its about 3,700 light-years away from us and has the shortest orbital period of any known black widow, just 62 minutes. That means the two objects are very close together; for a standard neutron star mass of 1.4 times the mass of the Sun, the companion has a mass just a twentieth of the Suns so about 50 times Jupiters and their orbit is only about 800,000 km across. Thats less than three times the distance of the Moon from the Earth.

That secondary object is getting fried.

Thats already strange, but it gets stranger. The mass of the second object is too small to be a normal star. Its possibly a brown dwarf, an object more than about 13 but less than about 77 times the mass of Jupiter. It might also be a star that was once like the Sun but lost a lot of mass to the pulsar, exposing its core. Whatever it is, its density is 10 grams per cubic centimeter, which is high. Twice as dense as Earth, and 10 times that of a normal star. On the low end for a brown dwarf, but again also possibly an old, mostly eaten stellar core.

The amount of energy the pulsar beams is staggering, about 10 times the Suns total energy output. The astronomers calculated the temperature of the secondary object, and found that on the side facing away from the pulsar beams its about 6,300C, but on the side facing into the beams its over 10,000C. Ouch. Those beams are heating it up by about 4,000 C, and likely that heat from the dayside carries over into the night side via circulation in the atmosphere. Interestingly thats hotter than many stars, so if that secondary is a brown dwarf its a whole lot different than other ones, which are generally pretty cool temperature-wise. And if its a stripped core that would be amazing to know as well.

Theres a third star too; the astronomers measured the motion of the pulsar through space and found another star traveling with it. If that actually is a second companion in what is then a trinary system, its pretty far removed, with the third star taking very roughly 10,000 years or so to orbit once. Thats a long way off, but still, what a view!

If you could survive it. I think I prefer seeing it from Earth. Still, the third star, if it is physically associated, will help astronomers understand this system, because somehow it stayed bound to the binary even at such a distance. A supernova is an exceedingly violent event; being able to keep a third star makes the physics tricky.

Everything about this object is tricky. I imagine astronomers will be looking to get more data on it because its full of surprises, and itll be a fun puzzle to solve. And thats one of the biggest reasons we observe the skies.

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Bad Astronomy | Black widow pulsar is zapping and eating its companion | SYFY WIRE - Syfy

Few subjects are as awe-inspiring and fascinating than the night sky, and we've just uncovered an archive of photos from NASA that are out of this world. Astronomy Picture of the Day is a free website that exists to bring you just that: every day a different image or photograph of the universe gets featured, and there's also a brief explanation written by a professional astronomer so that you can find out more about the shot.

For example, in the picture above by Ignacio Javier Diaz Bobilloy , the explanation on the Astronomy Picture of the Day NASA website reads: "The entire Carina Nebula, captured here, spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. While Eta Carinae itself maybe on the verge of a supernova explosion, X-ray images indicate that much of the Great Nebula in Carina has been a veritable supernova factory."

Wondering what the difference between astronomy and astrophotography is? Astronomy is the scientific study of celestial objects, space, and the physical universe, while astrophotography is "the use of photography in astronomy!"

You can see up to 35 years' (yes, years) worth of daily photos on the Archive to inspire your astrophotography. Why not bookmark the page and revisit for a daily dose?

And if you're keen to start taking stunning astronomical images yourself, why not discover the best cameras for astrophotography?

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Landscape astrophotography masterclassWhat is astrophotography and what camera equipment do you need?Best CCD cameras for astrophotography

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Astronomy picture of the day: discover 35 years' worth of amazing NASA images - Digital Camera World

Joshua Doucette found his academic and career paths through research, joining faculty-led teams in space physics and particle physics during his undergraduate years at Iowa. These rewarding experiences have launched his next phase: the pursuit of a doctorate in physics.

Story: Richard C. Lewis

Photography:Justin Torner

A simple request from Joshua Doucette opened his academic and careerpaths.

The fall of his first year at the University of Iowa, Doucette decided he wanted to do research in physics and astronomy. He emailed as many faculty members as he could find in the department who were looking for undergraduate help in theirlabs.

At the same time, Doucette was taking an introductory physics class taught byAllison Jaynes, assistant professor in the Department of Physics and Astronomy. Still looking for a research home, Doucette decided to ask Jaynes in person afterclass.

I knew who she was, and shes approachable, hesays.

One in-person meeting later, Doucette was hired. He joined Jayness research group that November and has been with her ever since. Doucette, a senior from Charles City, Iowa, who will graduate in May with a physics degree, has learned new programming languages, contributed to discoveries in space and particle physics, and won a summer research stint at the Brookhaven National Laboratory, operated by the U.S. Department of Energy. He will further his studies as he pursues a doctorate in physics at the University ofWisconsinMadison.

Doucette describes his involvement in research as rewarding in both short and longterms.

The research roles reward you in different ways, Doucette says. You may have a challenging programming problem, and you might need to spend a few hours to get that to work, and then its immediately rewarding to see you have built this application that furthers the research. Then, theres the long-term reward, which is, OK, now Ive built several programs, I can make all these graphs, Im putting in all this data gathered by the spacecraft and actually doing the analysis that leads to discoveries published in peer-reviewedjournals.

As an undergraduate, Doucette has won substantial funding for research-oriented awards and scholarships. Hes earned money from myriad entities, including the Iowa Center for Research by Undergraduates (ICRU), the U.S. ATLAS SUPER Program, the NASA Iowa Space Grant Consortium, and the UI Department of Physics andAstronomy.

His tip? Find the opportunity, andpounce.

First, youve got to apply. Thats the biggest thing, Doucette says, adding he made sure a faculty member reviewed his applications before he submittedthem.

The awards supported Doucettes varied researchadventures.

His first opportunities came with Jaynes, whose group was examining the Van Allen radiation belts, intense bubbles of energy surrounding Earth named for famed Iowa physicist James VanAllen.

Josh wrote original computer programs to determine the amount of high-energy electrons in the radiation belts, and how those levels change over time, using data from the Van Allen Probes spacecraft mission, says Jaynes, a co-investigator on the NASA-led mission. He also created a program that analyzes a proxy value of a type of magnetospheric wave, so we can estimate how many particles are being lost to the atmosphere from the radiationbelts.

Doucettes contributions earnedpraise.

Im amazed by Joshs abilities and enthusiasm, Jaynes says of the first-generation college student. Hes one of the strongest undergraduate students Ive everencountered.

In spring 2020, as a sophomore, Doucette joined the research group led byUsha Mallik, a particle physicist and professor in the Department of Physics and Astronomy. The next summer, he was selected to join scientists at Brookhaven National Laboratory on Long Island who were involved in investigating upgrades to ATLAS, one of two main detectors operating at the Large Hadron Collider, the particle accelerator that has yielded a host of revelations about the fundamental laws of physics and theuniverse.

I was involved in preparing for the upgrade. We need to have construction, and we need to have testing, Doucette says. And this needs to be done by technicians, not scientists, who chiefly will analyze data. So, people like me need to make software that is easy enough for the technicians to get their jobs done and to operate as automatically as possible.

Doucette chose Iowa after taking classes at North Iowa Area Community College. He says he was influenced partly by an outreach coordinator from the university who visited his highschool.

I told him I wanted to study physics, and he told me Iowa has a world-class, internationally recognized program in physics, Doucette recalls. In hindsight, I say thats the best choice I could havemade.

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Research Ambitions Yield Big Rewards | Physics and Astronomy - The University of Iowa - The University of Iowa

Blood moons? Old news. Lunar eclipses? To some observers, frankly un-spectacular. Aurora borealis? Good luck spotting that. If you're in the market for a celestial phenomenon that really makes its presence known in New York City, there's one word you should have on the tip of your tongue: Manhattanhenge.

Also known as the Manhattan Solstice, Manhattanhenge occurs when the sun comes into perfect alignment with parts of the city's street grid for a few blissful summer evenings. It happens every year around late May and mid-July, twice with a full sun and twice with a half sun, weather permitting. ("Full sun" and "half sun" refer to how much of the solar disk is visible above the horizon.)

"It's perfectly framed by the concrete jungle of New York City I like to call it 'astronomy in your face,'" said Dr. Jackie Faherty, an astrophysicist at American Museum of Natural History (AMNH) who has become the museum's henge-whisperer. "Manhattanhenge is the event of the summer for the celebration of astronomy."

It's an ideal NYC activity, whether you're interested in grabbing a sunset selfie with Helios' avatar behind you, or you just want to soak in the scene as locals and tourists thrust their iPhones toward the sky and jockey for position in the middle of 42nd Street as if they were extras from World War Z.

According to Faherty, it's beloved because it's an epic sunset happening at a time of year when New Yorkers are already flocking outdoors and looking for any reason to stay outside. It's also, as with everything related to sunsets, romantic, and provides a unique photo opportunity for our social media age. (Cityhenges also happen in other urban areas on a grid, including Chicago, Toronto and Montreal.)

"It is a fantastic picture with the sun lighting up the canyons of New York City, and those beautiful golden light hues of red and yellow and orange," Faherty said. "And so it becomes a special bonding moment for New Yorkers and visitors to the city."

You can find this year's dates, which were announced by MTA Away, below:

While the observable phenomenon goes back as long as Manhattan has had a grid, the actual term Manhattanhenge was first coined in the late 1990s by Neil deGrasse Tyson when he was working as an astrophysicist at the Hayden Planetarium at AMNH.

"He started to promote it as director of the planetarium, and as an homage to Stonehenge, which is probably the most famous henge or dedicated structure to a solar position," explained Faherty, AMNH's senior scientist in the Department of Astrophysics. "He decided that Manhattan gets to have its own henge."

Faherty started working at the museum around 2002, and despite Tyson spreading the info about Manhattanhenge on his "Starstruck" email list, it took several years to take off. "We'd get the emails from the director, and I was always like, 'Oh, yay!'" Faherty said. "And I would invite my friends, we would go outside and look for it, and no one was out there. This was not a popular phenomenon yet it had not spread."

She took it upon herself to start doing public programs on it at AMNH to bring more attention to the phenomenon. And as Tyson's fame grew, more and more people "started to pick up on it that way. Now it is what it is. It went viral. As an astronomical phenomenon might, this one went viral."

Around a decade ago, Tyson passed the Manhattanhenge baton to Faherty, who now calculates its dates and times each year. It's become one of her favorite parts of the job because of how much joy it brings to the city.

"You get people that are so friendly with each other all of a sudden," she said. "New Yorkers aren't known for talking to each other on the street, but this is a very curious city. So you could be out on a Manhattanhenge sunset moment, and cars are stopping and people are in the middle of the street, and everybody's just like, 'What's going on?' And you unify over that and chat, and that is beautiful and fun. You can learn something...and you can have a good conversation."

Faherty says there are tons of places in the city to watch the phenomenon, from 14th Street up to Washington Heights. She notes that despite the borough's symmetry, you should be mindful of things that break the grid and could get in the way of your view, like hills, buildings or Central Park. You may want to find the widest street possible to really get the full effect, but any street that has buildings you love will suffice.

Her top spots to view it include 145th Street (close to Broadway), 72nd Street, and 42nd Street, which remains the most popular spot for a reason. On 42nd Street, she particularly recommends either going to the Tudor City overpass or heading to Pershing Square by Grand Central the latter of which technically isn't legal because people end up blocking the taxis, but is a "super fun" spot always filled with professional photographers. She adds that Gantry Plaza State Park in Long Island City gets pretty great views as well.

And even if it's raining or overcast on the Manhattanhenge days, that doesn't mean you're out of luck. There'll be tons of gorgeous sunsets to witness between May 29th and July 12th because of what she has termed the "Manhattanhenge effect."

"The effect days can be just as gorgeous," she said. "Because what's happening between those two days is that the sun is still crossing your grid, it's really low in the sky. So you're in the golden hour, you're in that same moment where the beautiful sun rays are close to the horizon, and they're lighting up the canyons in yellows and oranges."

Because I am only human and not above the occasional attempt at capturing mother nature's je ne sais quoi on my phone, here are some tips on how to best photograph a sunset with your iPhone. And if you've never caught Manhattanhenge before, Gabe Elder made the video below showing the crowds of camera-emboldened onlookers in all their awkward glory at the Tudor City overpass in 2018.

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NYC's astronomical event of the summer: Here are the 2022 Manhattanhenge dates - Gothamist

This illustration is an artists impression of the thin, rocky debris disc discovered around the two Hyades white dwarfs. Rocky asteroids are thought to have been perturbed by planets within the system and diverted inwards towards the star, where they broke up, circled into a debris ring, and were then dragged onto the star itself. Credit: NASA, ESA, STScI, and G. Bacon (STScI)

White dwarfs were once normal stars similar to the Sun but then collapsed after exhausting all their fuel. Historically, these interstellar remnants have been difficult to study. A recent study from astronomers at Swedens Lund University, however, reveals new information about the movement patterns of these perplexing stars.

White dwarfs have a radius of about 1 percent that of the Suns. They have roughly the same mass, which means they have an astonishing density of about 1,000 kg (2,200 pounds) per cubic centimeter. After billions of years, white dwarfs will cool down to a point where they no longer emit visible light, and transform into so-called black dwarfs.

40 Eridani A was the first white dwarf discovered. It is a bright celestial body 16.2 light-years away from Earth, surrounded by a binary system consisting of the white dwarf 40 Eridani B and the red dwarf 40 Eridani C. Ever since it was discovered in 1783, astronomers have tried to learn more about white dwarfs in order to gain a deeper understanding of the evolutionary history of our home galaxy.

In a study published in the journal Monthly Notices of the Royal Astronomical Society, a research team can present new findings of how the collapsed stars move.

Illustration of Gaia with the Milky Way in the background. Gaia is an ambitious mission to chart a three-dimensional map of our Galaxy, the Milky Way, in the process revealing the composition, formation and evolution of the Galaxy. Credit: ESAD. Ducros, 2013

Thanks to observations from the Gaia space telescope, we have for the first time managed to reveal the three-dimensional velocity distribution for the largest catalog of white dwarfs to date. This gives us a detailed picture of their velocity structure with unparalleled detail, says Daniel Mikkola, doctoral student in astronomy at Lund University.

Thanks to Gaia, researchers have measured positions and velocities for about 1.5 billion stars. But only recently have they been able to completely focus on the white dwarfs in the Solar neighborhood.

We have managed to map the white dwarfs velocities and movement patterns. Gaia revealed that there are two parallel sequences of white dwarfs when looking at their temperature and brightness. If we study these separately, we can see that they move in different ways, probably as a consequence of them having different masses and lifetimes, says Daniel Mikkola.

The results can be used to develop new simulations and models to continue to map the history and development of the Milky Way. Through an increased knowledge of the white dwarfs, the researchers hope to be able to straighten out a number of question marks surrounding the birth of the Milky Way.

This study is important because we learned more about the closest regions in our galaxy. The results are also interesting because our own star, the Sun, will one day turn into a white dwarf just like 97 percent of all stars in the Milky Way, concludes Daniel Mikkola.

Reference: The velocity distribution of white dwarfs in Gaia EDR3 by Daniel Mikkola, Paul J McMillan, David Hobbs and John Wimarsson, 22 February 2022, Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/mnras/stac434

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Astronomers Map the Movement of White Dwarfs of the Milky Way - SciTechDaily

Researchers at the University of Victoria are among the first in history to find traces of the first stars in the universe.

Kim Venn, UVic astronomer and director of the Astronomy Research Centre, co-led an international team that found evidence of these post-Big Bang stars in a cluster with the lowest concentration of metals ever observed.

Using the European Space Agencys satellite mission Gaia, Venns team examined a cluster called C19 in the outer reaches of the Milky Way galaxy. The extremely metal-poor stars appeared to share an orbit in the galactic halo. After studying them using spectroscopy the study of how matter absorbs and emits light they determined theyd found what are believed to be traces of first stars.

What an amazing thing, isnt it? Stars that we will never be able to go and touch, that well never be able to send a robot to grab a piece of that atmosphere, and yet we can still figure out their composition from these rainbows, from these spectra, Venn said in an interview on uvic.ca.

Her team is already investigating another stellar cluster and is working on installing a new high-resolution spectrograph in Gemini South observatory in Chile. Thatll allow the team to search for similar stellar streams from the Southern Hemisphere.

New projects will come out of this discovery, like one in which UVic cosmologist Julio Navarro is participating. He has started working with an international team on a project to model the origins of C19 and determine what it could mean for how we understand dark matter.

In astronomy, we often say when it comes to objects theres zero, one, or many, Venn said. So far all weve done is gone from zero to one. Now that we know what to look for and how to find them, we want to find more.

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BC-led astronomy team discovers traces of the universe's first stars Summerland Review - Summerland Review

Why is Bennu spitting rocks into space?

This is one of the weirdest things it does, and thats saying something. Bennu is a small asteroid, only a little over 500 meters wide. Its shaped like two cones stuck together base-to-base. Its not a solid rock but is instead a rubble pile, like a bag of rocks held together by gravity. It has one huge boulder sticking out 22 meters high called Benben Saxum.

And, also, well, its spitting rocks out into space.

Bennu is a near-Earth asteroid, moving around the Sun on a mildly elliptical orbit about the same size as Earths orbit. It can get as close as half a million kilometers to us, so its classified as a Potentially Hazardous Object, though at least for the next three centuries it wont get close enough to us to be a real threat. Still, we want to know more about these rocks that could potentially hit us and ruin our day, so NASA sent the OSIRIS-REx mission there to map Bennu and eventually return samples to Earth for scientists to study.

One of the many discoveries from that mission is that Bennu is, somehow, shooting small rocks from its surface into space. That was one of the biggest surprises from the mission, and its not clear how this is happening. One likely cause is small micrometeorite impacts hitting the surface and blasting away shrapnel. Another is thermal stress: The day/night cycle as Bennu spins makes the rocks on the surface expand and contract as they enter and leave sunlight, which eventually cracks them. This can fling small bits away.

The sizes of these spitballs seen went from very small up to about 10 centimeters across. The gravity on Bennu is hardly more than a whisper, just a few millionths of Earths, but if you can reach back to the dim memories of high school science you might recall the van der Waals force, where some closely packed molecules attract or repel each other due to their electron clouds. This force is weak but in an asteroid whose surface is made up of jagged rocks it can help be a cohesive force holding the asteroid together. This too has to be overcome, and launching a rock the size of your fist away at speeds of a few centimeters to a few meters per second takes some effort, so its impressive Bennu can muster that kind of oomph.

But is that the only way rocks are ejected? Just because we can think of two that cover most of the bases doesnt mean they cover all of them. So a team of scientists looked into another possible launching mechanism: Electrostatic charge [link to paper].

Ultraviolet light from the Sun packs quite a punch, and when a UV photon hits the surface of Bennu it can flick away an electron from an atom there. As more hit and more electrons are lost the rocks gain a positive charge. If enough charge builds up, a rock can feel a force repelling it from its fellow rocks, and that could be enough to overcome the meager gravity and launch it into space.

The Sun also blows a wind of charged subatomic particles, and this solar wind can also hit the surface and build up a static charge, and in the end can also launch bits of rock into space. Its the cosmic equivalent of rubbing a balloon on your hair and sticking it to a wall, though in that case you get an attractive force instead of a repelling one, but its the same physics.

This electrostatic charge buildup is almost certainly happening on Bennu, but what the scientists investigated is the possibility that it actually is strong enough to spit rocks away. What they found is that it can, but the force is pretty small so it only works if the rock is small enough; assuming no van der Waals cohesion rocks up to roughly a centimeter in size can be flung away. So this is likely not the reason we see the bigger ones ejected, but it could ping away smaller ones.

Interestingly, some of the rocks seen ejected were on the night side of Bennu. Sunlight cant explain those at all, obviously, but the solar wind still could. As the particles blow past Bennu it blocks them on the day side, leaving a shadow behind it, a hole, like if you were to stand downwind of a building to get out of the wind. This is called a plasma wake, and the physics is pretty fierce but the magnetic field of the wind can still connect to the surface on the lee side of the asteroid, allowing particles to hit there. However, modeling this, the scientists found the force is far weaker, too weak to explain the rocks launched away during local night on Bennu.

So it looks like electrostatic charging is at best a minor force at work here, but this is still valuable research. For one, it can still work on the smallest bits and probably is very good at lofting dust off the surface. Also, the electrostatic cohesive properties of rubble pile asteroids isnt well known, so a study like this is a good step in figuring that out.

There will be a time in the future when a small bag of rocks like Bennu is aimed right at us, and we have to do something about it so it doesnt hit. In that case the more we know about it, especially the forces holding it together, the better. We probably wouldnt want to blow it up but instead push it aside, but even then we need to understand its structure to be able to do that.

Its not every day that astronomy can literally save the world, but that day will come.

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Electrostatic repulsion may be lofting small rocks off the asteroid Bennu - Syfy