|
Post by auntym on Sept 7, 2018 12:57:39 GMT -6
www.space.com/41748-milky-way-glitters-in-spectacular-photo.html?utm_source=dlvr.it&utm_medium=twitter Behold, the Milky Way! Our Galaxy Glitters in This Spectacular PhotoBy Miguel Claro, Space.com Contributor / September 7, 2018 A paannamic view captured from the village of Campinho in Portugal's Dark Sky Alqueva Reserve shows the arc of the Milky Way as seen during a spring night in the Northern Hemisphere. The scene also includes Mars, Saturn and Jupiter. Credit: Miguel Claro Miguel Claro is a professional photographer, author and science communicator based in Lisbon, Portugal, who creates spectacular images of the night sky. As a European Southern Observatory photo ambassador, a member of The World At Night and the official astrophotographer of the Dark Sky Alqueva Reserve, he specializes in astronomical skyscapes that connect Earth and the night sky. Join Miguel here as he takes us through his photograph "A Spring Arch of Milky Way." The starry arc of the Milky Way galaxy sprawls across the evening sky on a spring night in this photo captured near the village of Campinho in Portugal's Dark Sky Alqueva Reserve. For skywatchers in the Northern Hemisphere, the Milky Way makes its first appearance of the year in spring after hiding beneath the horizon during the winter months. This photo was taken on April 18, 2018 at 3:40 a.m. local time (0230 GMT), about 3 hours before sunrise. [How to See the Milky Way in the Summer Night Sky] Visible high above the arc of the Milky Way is the bright-blue star Vega, which shines with an apparent magnitude of 0.0 (Vega is used as the standard reference star on the scale of stellar magnitude). Located in the Lyra constellation, Vega forms an asterism, or star pattern, well known as the Summer Triangle along with the stars Deneb (in the Cygnus constellation) and Altair (in the constellation Aquila). Glowing red just below the right end of the Milky Way's arc is Mars, and Saturn is shining to its right, near the dusty core of the galaxy. Tracing the line formed by Mars and Saturn farther to the right, we can find the red supergiant star Antares in the Scorpius constellation followed by the bright planet Jupiter. Above the horizon, yellow-green airglow mixes with the lights from the Portuguese village of Aldeia da Luz. Below, water from the Great Lake of Alqueva — the largest man-made lake in Europe — mirrors the starry night sky. Editor's note: If you captured an amazing astronomy photo and would like to share it with Space.com for a story or gallery, send images and comments to managing editor Tariq Malik at spacephotos@space.com. To see more of Claro's amazing astrophotography, visit his website, www.miguelclaro.com. www.space.com/41748-milky-way-glitters-in-spectacular-photo.html?utm_source=dlvr.it&utm_medium=twitter
|
|
|
Post by swamprat on Nov 16, 2018 14:45:46 GMT -6
|
|
|
Post by auntym on Jan 31, 2019 14:15:50 GMT -6
spacetelescope.org/images/opo0014a/?utm_source=Twitter&utm_medium=social&utm_campaign=SocialSignIn Galactic silhouettesThrough an extraordinary chance alignment, the Hubble telescope has captured a view of a face-on spiral galaxy lying precisely in front of another larger spiral. The unique pair is called NGC 3314. This line-up provides astronomers with the rare chance to see the dark material within the foreground galaxy, seen only because it is silhouetted against the light from the object behind it. NGC 3314 lies about 140 million light-years from Earth in the direction of the southern hemisphere constellation Hydra. This picture is one of many produced by the Hubble Heritage Program, created 1-1/2 years ago to publicly release some of the best celestial views taken by the telescope's visible-light camera. Now, the International Center of Photography in New York City has rewarded the program for its work with the annual Infinity Award for Applied Photography. Credit: NASA/ESA and The Hubble Heritage Team (STScI/AURA) spacetelescope.org/images/opo0014a/?utm_source=Twitter&utm_medium=social&utm_campaign=SocialSignIn
|
|
|
Post by auntym on Feb 7, 2019 15:03:07 GMT -6
curiosity.com/topics/an-undiscovered-galaxy-just-photobombed-the-hubble-telescope-curiosity An Undiscovered Galaxy Just Photobombed the Hubble TelescopeFebruary 6, 2019 by Elizabeth Howell / When NASA compares a scientific discovery to a game of "Where's Waldo?", you know something fun will be announced. It turns out the Hubble Space Telescope discovered a dwarf galaxy in our stellar neighborhood. The best thing about this find is it was completely accidental. Loner GalaxyWhat the telescope was really doing was photographing a star cluster called NGC 6752, which is 13,000 light-years away — a respectable distance by cosmic standards. (A light-year is the distance light travels in a year; our own Milky Way galaxy is about 100,000 light-years across.) So imagine astronomers' surprise when a "loner" galaxy popped up in the image. It was super-tiny and super-faint, but scrutiny showed that this tiny, 3,000-light-year-across galaxy was something like 30 million light-years away from us. That's about 12 times further than the Andromeda Galaxy, a bright object that northern hemisphere observers can see with the naked eye (no telescopes or binoculars needed). Now that astronomers know where this galaxy is hiding, they promise us that it will teach us more about how galaxies change as they grow and age. In fact, this galaxy is almost as old as our universe itself, which is estimated at 13.7 billion years. "Because of its 13-billion-year-old age, and its isolation — which resulted in hardly any interaction with other galaxies — the dwarf is the astronomical equivalent of a living fossil from the early universe," NASA said in a statement. CONTINUE READING & WATCH VIDEO: curiosity.com/topics/an-undiscovered-galaxy-just-photobombed-the-hubble-telescope-curiosity
|
|
|
Post by swamprat on Feb 8, 2019 10:31:11 GMT -6
When will the Milky Way and Andromeda galaxies collide?By EarthSky in SPACE | February 8, 2019
The Andromeda galaxy is the nearest large spiral to our Milky Way. Astronomers have suspected for some time it will eventually collide with our Milky Way. Now – thanks to the Gaia satellite – they know more.
Boom! Future motions of the Milky Way and Andromeda galaxies show them on a collision course. Meanwhile, the 3rd major galaxy in our Local Group – the Triangulum galaxy – is likely to give the collision a wide berth. Image via ESA/Gaia/DPAC.
Astronomers have said for some time that the nearby Andromeda galaxy – also known as M31, nearest large spiral galaxy to our home Milky Way – will one day collide with the Milky Way. On February 7, 2019, the European Space Agency (ESA) provided an update on the newest insights about this impending collision, based on data from its Gaia satellite. Across the course of 2018, astronomers announced multiple, very interesting discoveries about our galaxy, based on Gaia’s second data release last April. Now Gaia has looked beyond the Milky Way, at the motions of stars within both the Andromeda galaxy and the Triangulum galaxy (aka M33), which is the third large galaxy in our Local Group. The data reveal some surprises about the Andromeda galaxy’s collision course with the Milky Way.
The first surprise is a new estimate for when the collision will occur. Astronomers thought it would happen some 3.9 billion years from now. But the astronomers who studied Gaia’s data said they now believe it’ll happen 600 million years later than previously estimated, perhaps 4.5 billion years from now. What’s more, they said, the Andromeda galaxy is:
"… likely to deliver more of a glancing blow to the Milky Way than a head-on collision."
These results were published February 7 in the peer-reviewed Astrophysical Journal. Astronomer Roeland van der Marel of the Space Telescope Science Institute in Baltimore – who led the study – commented:
"We needed to explore the galaxies’ motions in 3D to uncover how they have grown and evolved, and what creates and influences their features and behavior.
We were able to do this using the second package of high-quality data released by Gaia."
Gaia does what is called astrometry. Its job is to scan the sky repeatedly, observing each of its targeted billion-plus stars an average of 70 times over its five-year mission. Again and again and again, Gaia will acquire data points on the positions of stars in the Milky Way, and now in the Andromeda and Triangulum galaxies, too. We know that stars move through space. Gaia will tell us, exactly, how they moved during that five-year period.
It may not sound very dramatic. But it is. That much knowledge about star motions – actual data on the motions of more than a billion stars – is unprecedented in the history of astronomy. That is why there have been so many astounding discoveries from Gaia already.
Ultimately, Gaia’s data will be used to build the most precise 3D map of the stars in the nearby universe, ever. A statement from ESA explained:
"Previous studies of the Local Group have combined observations from telescopes including the NASA/ESA Hubble Space Telescope and the ground-based Very Long Baseline Array to figure out how the orbits of Andromeda and Triangulum have changed over time. The two disk-shaped spiral galaxies are located between 2.5 and 3 million light-years from us, and are close enough to one another that they may be interacting.
Two possibilities emerged: either Triangulum is on an incredibly long six-billion-year orbit around Andromeda but has already fallen into it in the past, or it is currently on its very first infall.
Each scenario reflects a different orbital path, and thus a different formation history and future for each galaxy."
That was where things stood until Gaia came along.
Mark Fardal, also of Space Telescope Science Institute, is second author on the new paper. He explained:
"We combed through the Gaia data to identify thousands of individual stars in both galaxies, and studied how these stars moved within their galactic homes.
While Gaia primarily aims to study the Milky Way, it’s powerful enough to spot especially massive and bright stars within nearby star-forming regions – even in galaxies beyond our own."
The stellar motions measured by Gaia not only reveal how each of the galaxies moves through space, but also how each rotates around its own spin axis, ESA said, adding:
"A century ago, when astronomers were first trying to understand the nature of galaxies, these spin measurements were much sought-after, but could not be successfully completed with the telescopes available at the time."
Roeland said:
"It took an observatory as advanced as Gaia to finally do so. For the first time, we’ve measured how M31 and M33 rotate on the sky. Astronomers used to see galaxies as clustered worlds that couldn’t possibly be separate ‘islands’, but we now know otherwise.
It has taken 100 years and Gaia to finally measure the true, tiny, rotation rate of our nearest large galactic neighbor, M31. This will help us to understand more about the nature of galaxies."
Bottom line: An analysis of data from Gaia’s second data release revealed an longer-than-expected timeline for the impending collision between our Milky Way galaxy and the neighboring Andromeda galaxy. The data also show that the collision is likely to be a glancing blow, rather than the head-on crash that had been expected previously.
Sharpest-ever view of the Andromeda Galaxy, via the Hubble Space Telescope is at the URL below. On the right side, scroll down and click on "zoomable" feature to be mesmerized. You can zoom in and out. If you're bored and have some spare time, magnify and start counting stars.....:
spacetelescope.org/images/heic1502a/
|
|
|
Post by swamprat on Mar 14, 2019 9:12:10 GMT -6
Galaxy with a tailBy Eleanor Imster in TODAY'S IMAGE | March 14, 2019
This striking image shows just a part of the spectacular tail emerging from a spiral galaxy nicknamed D100.
Image via ESA/Hubble & NASA, Cramer et al.
This image, created by combined data from the Hubble Space Telescope and the Subaru Telescope in Hawaii, shows just a part of the tail emerging from a spiral galaxy nicknamed D100.
Galaxy D100 is a member of the huge Coma Cluster. One of the most populated galaxy clusters known, the Coma Cluster is thought to contain as many as 10,000 galaxies and to stretch 20 million light-years from side to side.
D100 got its spectacular tail of gas – which stretches far beyond the left side of this image – when pressure from the cluster’s hot constituent plasma (known as the intracluster medium) stripped gas from D100 and tore it away from the galaxy’s main body, drawing it out into the plume you can see in the image above.
Here’s more from the ESA explaining the phenomenon:
Tails such as these are created by a process known as ram-pressure stripping. Despite appearances, the space between galaxies in a cluster is far from empty; it is actually filled with superheated gas and plasma, which drags and pulls at galaxies as they move through it, a little like the resistance one experiences when wading through deep water. This can be strong enough to tear galaxies apart, and often results in objects with peculiar, bizarre shapes and features — as seen here.
Bottom line: Image of a spiral galaxy with a tail.
earthsky.org/todays-image
|
|
|
Post by auntym on Mar 15, 2019 14:58:58 GMT -6
www.universetoday.com/141750/this-is-what-itll-look-like-when-the-milky-way-and-andromeda-galaxies-collide-billions-of-years-from-now/ This is What It’ll Look Like When the Milky Way and Andromeda Galaxies Collide Billions of Years from NowPosted on March 13, 2019 by Evan Gough / www.universetoday.com/author/evan-gough/Located in the constellation of Hercules, about 230 million light-years away, NGC 6052 is a pair of colliding galaxies. Image Credit: ESA/Hubble & NASA, A. Adamo et al.This is What It’ll Look Like When the Milky Way and Andromeda Galaxies Collide Billions of Years from Now What happens when two galaxies collide? The Milky Way and the Andromeda Galaxy are on a collision course, and in about 4.5 billion years, they will meet. Now astronomers using the Hubble have provided some visual insight into what that collision might look like. When two galaxies collide, it’s highly unlikely that any stars will actually collide with one another. There is a vast distance between stars, and it’s measured in light years. So even though galaxies are enormous conglomerations of stars, when two galaxies collide, it’s extremely rare for two stars to actually meet. Instead, the gravitational interactions between all the stars will alter their trajectories. This is what’s happening in NGC 6052. When NGC 6052 was first discovered in 1784 by William Herschel, he thought it was a single galaxy. It was classified as an irregular galaxy because of its odd shape. But now we know different. Now we know it’s actually two different galaxies merging into one. The two galaxies are named NGC 6052A and NGC 6052B. The pair are in the late stages of their merger, and once things settle down, it will be a stable galaxy, and we can call it just NGC 6052 again. The leading image was taken with the Wide Field Camera 3 (WFC3) on the NASA/ESA Hubble Space Telescope. But the Hubble also imaged the galaxies in December 2015 with its Wide Field Planetary Camera 2 (WFPC2). The Hubble captured this image of NGC 6052 A and B in December 2015 with its Wide Field Planetary Camera 2 (WFPC2.) Merging galaxies can be a beautiful site, as the gravitational forces draw long wispy streams of stars into fluid-like shapes. The Mice galaxies, NGC 4676 A and B are in the process of merging and are one of the most striking examples of merging galaxies. CONTINUE READING: www.universetoday.com/141750/this-is-what-itll-look-like-when-the-milky-way-and-andromeda-galaxies-collide-billions-of-years-from-now/
|
|
|
Post by auntym on Mar 16, 2019 15:25:26 GMT -6
www.astronomy.com/magazine/ask-astro/2019/01/andromeda-distance?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter The Andromeda Galaxy is moving toward the Milky WayThe Andromeda Galaxy is speeding toward us, but it will take 4 billion years to get here. This artist’s concept shows the night sky from Earth in 3.75 billion years: Andromeda is much closer, appears larger, and has begun to distort the plane of the Milky Way with its gravitational pull. NASA, ESA, Z. Levay and R. van der Marel/STScI, T. Hallas, and A. MellingerThe Andromeda Galaxy is moving toward the Milky Way from 2.5 million light-years away. Today, we see it as it was 2.5 million years ago. Wouldn’t its actual position be 2.5 million light-years closer, and shouldn’t it be colliding with our galaxy now? Published: Wednesday, January 23, 2019 NASA, ESA, Z. Levay and R. van der Marel/STScI, T. Hallas, and A. Mellinger Ever since we could measure the movement of Andromeda, we’ve known it was on a collision course with the Milky Way. Fortunately, a galaxy is much heftier than a photon, and it is not flying toward us at the speed of light, so we have a little more than 2.5 million years to prepare. To figure out how soon this collision will occur, first we have to figure out how fast Andromeda is moving. We do this by observing the galaxy and comparing what we expect to see from a galaxy at rest to what we actually see from Andromeda. Things moving away from us have light that is Doppler shifted toward the red end of the spectrum; things moving toward us have light shifted toward the blue. Based on Doppler shifting of its light, Andromeda is speeding toward us at 68 miles per second (110 kilometers per second). Compare this to the light from Andromeda, which is moving toward us at 186,000 miles per second (300,000 km/s). So how much closer to collision with Andromeda have we come in the past 2.5 million years? If we assume Andromeda has been moving at the same speed without accelerating, then in the last 2.5 million years, Andromeda has moved only 900 light-years closer to us. Considering that the galaxy itself is 110,000 light-years across (give or take; this number is continually being revised), this is a small but significant mosey. But our assumption isn’t totally correct. As Andromeda gets closer, the gravitational attraction between it and the Milky Way gets stronger and Andromeda accelerates in our direction. On top of that, there’s one more factor we don’t know well: Is Andromeda headed straight for us, or is it aimed off to the side? Right now, we know that if there is any offset, it’s pretty small (less than the size of a pixel on the Hubble Space Telescope’s detector). However, even a small angle between Andromeda and the Milky Way will affect when and how the two galaxies collide, which stars will be flung out of the galaxies, and which will stay in. Think about playing golf or baseball or tennis — the movement of the ball changes when you don’t hit it head on. Unless something radically changes Andromeda’s course, current estimates say that we’re only about 4 billion years from a catastrophic collision that will leave us inside a merged remnant of what was once two separate galaxies. Valerie Mikles www.astronomy.com/magazine/ask-astro/2019/01/andromeda-distance?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter
|
|
|
Post by auntym on Mar 21, 2019 13:54:00 GMT -6
medium.com/starts-with-a-bang/could-the-milky-way-be-more-massive-than-andromeda-38725096d016 Could The Milky Way Be More Massive Than Andromeda?The only other large galaxy in the local group is larger in size and has more stars. But mass? Perhaps we’re the biggest, after all.by Ethan Siegel / medium.com/@startswithabangMar 21, 2019 The Milky Way, as we know it today, hasn’t changed much in billions of years, and neither has Andromeda. For a long time, we thought that Andromeda was larger, more massive, and contained far more stars than we did. But new observations have changed the story; now, we’re not so sure. (ESO/S. GUISARD)The Milky Way is home to the Sun, our Solar System, and hundreds of billions of stars beyond that. Yet unlike all the other galaxies out there — in our Local Group and in the Universe beyond — we have no good way to view our own galaxy from our position within it. As a result, the full extent of our galaxy, including its total size, mass, matter content, and number of stars, remains mysterious to modern astronomers. We’ve long looked at the galaxies surrounding our local neighborhood in space and compared ourselves to them. Although there may be more than 60 galaxies present within the Local Group, two of them dominate in every way imaginable: ourselves and Andromeda. We are the two largest, most massive galaxies around, with more stars than all the others combined. But which one is bigger? Long thought to be Andromeda, we’re now finding out the Milky Way might have a chance at being number one. Our Local Group of galaxies is dominated by Andromeda and the Milky Way, but we still don’t know which one dominates in terms of gravitation. While Andromeda appears to be larger in physical extent and have more stars, it may yet be less massive than we are. (ANDREW Z. COLVIN)It might strike you as a tremendous failing on the part of astronomers that we haven’t yet learned how big, massive, or full of stars our own galaxy is, but it shouldn’t surprise you. Think about it from another point of view: imagine you were looking out at a room of people, and you wanted to determine what everyone’s eye color was. It seems like the easiest experiment of all. All you’d have to do is get close enough to everyone in the room to see what color their eyes were, and you’d know. You’d likely know the eye color of everyone close to you right away, and through use of a tool — a camera, a pair of binoculars, a telescope, etc. — you could determine the eye color of everyone within your view. There’d only be one person in the room who’d give you trouble: yourself. CONTINUE READING: medium.com/starts-with-a-bang/could-the-milky-way-be-more-massive-than-andromeda-38725096d016
|
|
|
Post by auntym on Apr 13, 2019 12:34:39 GMT -6
mysteriousuniverse.org/2019/04/the-way-cities-grow-on-earth-mirror-how-galaxies-are-formed-in-space/
The Way Cities Grow on Earth Mirror How Galaxies Are Formed in Spaceby Sequoyah Kennedy / mysteriousuniverse.org/author/skennedy/April 13, 2019 People are a lot more predictable than we like to pretend. Sociologists have a set of laws they use to predict how large groups of people will behave—how populations shift, how likely two people are to become friends, how population distribution between cities in a given country will shake out. One such law is called Zipf’s law which predicts the populations of cities in a given country with spooky accuracy. Zipf’s law says that populations of cities will be inversely proportional to the city’s rank. If the most populous city in a country has 10 million people, the second most populated city will have a population of 10 million divided by two, the third most populous city will have a population of 10 million divided by three, and so on and so on until you get to the city ranked 10 millionth on the list which is just a dude in a treehouse. Zipf’s law has been accepted as true by sociologists, but until now there was no theoretical framework for why. It was simply based off what sociologists have observed. Well, now there’s a potential answer for why: it was written in the stars. Or, more accurately, galaxies. A recent paper by Henry Lin and Abraham Loeb at the Harvard-Smithsonian Centre for Astrophysics in Cambridge proposes that there is a grand, unifying principal behind all scaling laws—like Zipf’s law—based on the way galaxies formed at the beginning of the universe. They write: “We treat the population density as the fundamental quantity, thinking of cities as objects that form when the population density exceeds a critical threshold. The situation is therefore conceptually and mathematically analogous to the formation of galaxies in the universe.” This is just a big old space-city.Using publicly available population data and the decades of cosmological work done studying galaxies, Lin and Loeb showed that the models that determine the spread and makeup of galaxies can be used to predict human population scaling. Each time they used their galaxy-based model to predict population changes, they came to the exact equations that were already present in sociologists’ scaling laws. And it wasn’t just city size. They found a galactic explanation for the laws governing whether two people become friends, the spread of sexually transmitted diseases, and other complex human interactions. They write: ”We derive a simple statistical model that explains all of these scaling laws based on a single unifying principle involving the random spatial growth of clusters of people on all scales.” Paris And this is just a little people-galaxy.It’s pretty wild, but it’s hard to be surprised by it. After all, we’re made of star stuff, and whether you’re a person or a galaxy, math is math. And while this is hard science, it’s a principal that’s been espoused for very long time by people that don’t really understand what they’re saying: as above, so below. The math that governs galaxies is the same math that governs human populations. I don’t know if I’m awe-struck by that, or depressed. Maybe a little bit of both. mysteriousuniverse.org/2019/04/the-way-cities-grow-on-earth-mirror-how-galaxies-are-formed-in-space/
|
|
|
Post by auntym on Jan 15, 2020 15:56:47 GMT -6
www.cnet.com/news/strange-objects-discovered-orbiting-milky-ways-supermassive-black-hole/?TheTime=2020-01-15T19%3A17%3A57&ftag=COS-05-10aaa0b&ServiceType=twitter&PostType=link&UniqueID=BD32950E-37CB-11EA-AD97-59D539982C1E Strange objects discovered orbiting Milky Way's supermassive black hole Ain't nuthin' but a G thang -- four new G thangs, to be exact.by Jackson Ryan / www.cnet.com/profiles/jacksonryan/January 15, 2020 At the heart of the Milky Way, there's a monster black hole with a mass 4 million times that of the sun, Sagittarius A* (Sgr A*). In the last decade, scientists looking in the black hole's cosmic neighborhood saw two peculiar objects, which seemed to be orbiting the black hole. They were dubbed G1 and G2. The nature of these so-called "G sources" is controversial. Some astronomers believe they're gas clouds, others contend they look more like strange stars shrouded in dust. In a new study, astronomers reveal they have detected four more of these mysterious objects which look very similar to G1 and G2 -- and suggest they are members of a new class of cosmic phenomena. "These objects look like gas and behave like stars," said Andrea Ghez, an astronomer at UCLA and co-author of the new study, published in the journal Nature on Wednesday. Using near-infrared data collected over the last 13 years by the Osiris imager, installed at the W.M. Keck Observatory in Hawaii, the team were able to study the mysterious objects in greater detail. And they had a good template to work from -- both G1 and G2 have been studied fairly intensely and G2, in particular, has enraptured astronomers in the past. In 2014, astronomers observing G2 watched on as it barreled directly towards Sgr A*. Astronomers predicted G2 was a gas cloud and so it would offer the massive black hole a snack -- as it approached it would be ripped apart and gas would fall into the black hole. But... that's not what happened. G2 got perilously close to Sgr A* and survived, prompting a rethink about what it could be. "G2 survived and continues happily on its orbit; a gas cloud would not do that," said Ghez, back in 2014. G1 also survived its own close encounter, relatively unchanged. Ghez postulated what astronomers were seeing was not a gas cloud, but the product of merged binary stars, after two stars orbiting each other collided and formed a single, massive star. CONTINUE READING: www.cnet.com/news/strange-objects-discovered-orbiting-milky-ways-supermassive-black-hole/?TheTime=2020-01-15T19%3A17%3A57&ftag=COS-05-10aaa0b&ServiceType=twitter&PostType=link&UniqueID=BD32950E-37CB-11EA-AD97-59D539982C1EUCLA NEWSROOM: newsroom.ucla.edu/releases/astronomy-strange-objects-galaxy-black-hole
|
|
|
Post by auntym on May 3, 2020 12:03:13 GMT -6
astronomy.com/magazine/2019/02/a-universe-of-galaxies?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter A universe of galaxies The universe is awash in islands of matter — some 100 billion galaxies make up the basic building blocks of the cosmos.
By David J. Eicher / astronomy.com/authors/david-eicher February 22, 2019 Our galaxy, the Milky Way, explodes with color in this image taken in Chile’s high Atacama Desert, perhaps the darkest sky on Earth. The semicircular arc of the Milky Way is peppered with bluish and pinkish light from glowing star clusters and nebulae. The Large and Small Magellanic Clouds lie above and to the right of the Milky Way. P. Horalek/ESOOn the evening of October 4, 1923, near Los Angeles, a young astronomer got into his car and began a motorized trek up to Mount Wilson. There, he arrived at the observatory that housed the 100-inch Hooker Telescope, at the time the largest telescope in the world. Edwin Hubble was a fourth-year astronomer at Mount Wilson; he enjoyed using the Hooker Telescope because he was interested in, among other things, studying spiral “nebulae.” These mysterious gas clouds were scattered across the sky, and no one understood their nature. In the early days of the 1920s, Hubble had assigned himself the task of figuring them out. He pointed the great telescope toward his favorite object: the nebula in Andromeda, M31. This spiral-shaped cloud is faintly visible to the naked eye under a clear, moonless sky. He then captured its image on a photographic plate. Hubble was excited by the result. On it, he found a suspected nova, an exploding star. The next night, he photographed M31 again, hoping to catch the nova and record it under better atmospheric stability. The second plate did indeed record the nova, but little did he know, he also had captured a plate that would become legendary in the history of science. His observing time over, he returned to his office to analyze the catch. Suddenly, Hubble made an astonishing realization: The nova was not a nova at all, but a particular type of star that changed its brightness, a Cepheid variable. Checking earlier plates, he was able to confirm that, and he realized that the star’s faintness had incredible implications. The star, and the nebula that encompassed it, must lie at a distance of a million light-years — three times larger than anyone at the time believed the size of the whole universe to be. Today, thanks to improved measurements, astronomers know the object is 2.5 million light-years away. Aided in part by earlier work done by Vesto M. Slipher and by his own colleague Milton Humason, Hubble had at once discovered that the universe was far larger than anyone had believed, and that spiral nebulae like Andromeda were actually distant galaxies. They were whole systems of stars and gas, separated from our own Milky Way by a long hike. CONTINUE READING: astronomy.com/magazine/2019/02/a-universe-of-galaxies?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter
|
|
|
Post by auntym on May 3, 2020 22:00:50 GMT -6
|
|
|
Post by auntym on May 23, 2020 13:23:07 GMT -6
www.cnn.com/2020/05/23/world/distant-galaxy-wolfe-disk-scn-trnd/index.html?utm_medium=social&utm_term=link&utm_content=2020-05-23T17%3A33%3A04&utm_source=twCNN Astronomers find the Wolfe Disk, an unlikely galaxy, in the distant universeBy Ashley Strickland, CNN / www.cnn.com/profiles/ashley-strickland-profile Sat May 23, 2020 (CNN)Astronomers have spotted a massive disk galaxy, not unlike our own, that formed 12.5 billion years ago when our 13.8 billion-year-old universe was only a tenth of its current age. But according to what scientists know about galaxy formation, this one has no business being in the distant universe. This discovery is challenging how astronomers think about galaxy formation in the early universe. It's known as Galaxy DLA0817g, but astronomers nicknamed it the Wolfe Disk after late astronomer Arthur M. Wolfe, former doctoral advisor to three of the study's four authors. It represents the most distant rotating disk galaxy they have ever observed, thanks to the Atacama Large Millimeter/submillimeter Array of telescopes in Chile known as ALMA. CONTINUE READING: www.cnn.com/2020/05/23/world/distant-galaxy-wolfe-disk-scn-trnd/index.html?utm_medium=social&utm_term=link&utm_content=2020-05-23T17%3A33%3A04&utm_source=twCNN
|
|
|
Post by auntym on May 23, 2020 13:52:10 GMT -6
astronomy.com/magazine/2019/02/welcome-to-the-neighborhood?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter A guide to our galactic neighborhood The Milky Way and Andromeda rule over a motley collection of a few dozen galaxies.By Richard Talcott / Published: Friday, February 22, 2019 Andromeda, Pinwheel, the Magellanic Clouds, oh my! Learn all about the galaxies sitting in the Milky Way's back yard.The Andromeda Galaxy (M31) stands as the largest member of the Local Group. This view shows the dusty spiral arms that make up its disk and its yellowish galactic bulge. Also note two of its satellite galaxies: M32 (left of center) and NGC 205 (at lower right). Hunter WilsonA century ago, most astronomers believed our galaxy was the whole universe. That changed abruptly in 1923 when American astronomer Edwin Hubble discovered Cepheid variable stars in the large “spiral nebula” in the constellation Andromeda. Because the periods of these stars correlate with their luminosities, Hubble could deduce their distances. He concluded that the stars — and the spiral nebula to which they belong — must lie far beyond the Milky Way. That spiral galaxy, now known as the Andromeda Galaxy (M31), shares many characteristics with our own. Both are barred spiral galaxies with hundreds of billions of stars and disks that span more than 100,000 light-years. And even though astronomers long thought M31 outweighed the Milky Way by two or three times, recent studies hint that the two may have similar masses. These two giants — cosmic neighbors 2.5 million light-years apart — anchor our Local Group of galaxies. This gravitationally bound collection spans about 10 million light-years and contains more than 54 members. At least, that’s how many astronomers have detected so far. Finding small, dim galaxies taxes even Earth’s biggest telescopes, so quite a few more likely lurk in the shadows of their big brothers. Finding these low-luminosity companions and studying how they interact with their siblings will help astronomers understand the evolution and ultimate fate of our home galaxy. CONTINUE READING: astronomy.com/magazine/2019/02/welcome-to-the-neighborhood?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter
|
|
|
Post by auntym on Jul 4, 2020 12:37:00 GMT -6
ok...this is eye-opening
|
|
|
Post by auntym on Feb 12, 2021 23:33:51 GMT -6
astronomy.com/magazine/weirdest-objects/2015/12/1-fermi-bubbles?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitterWeird Object: Fermi BubblesNo. 1: Double Bubble, Toil and TroubleBy Bob Berman / astronomy.com/authors/bob-berman Friday, December 25, 2015 FERMI-MENT FILLER. Enormous expanding bubbles of ultra-powerful gamma rays, each centered on nothingness, meet at our galaxy’s core, as depicted in this illustration of the Milky Way. Discovered in 2010, the origin of these bubbles remains a complete mystery. NASA’s Goddard Space Flight Center In November 2010, astronomers using NASA’s Fermi Gamma-ray Space Telescope announced an astonishing discovery. Emanating from the center of our Milky Way Galaxy are two bubbles made solely of powerful gamma rays. This would have been strange enough if the bubbles, expanding at 2.2 million mph (3.5 million km/h), were concentric — a bubble within a bubble — with both centered at the galaxy’s core. But no, the two enormous spheres each hover in seemingly empty space above and below the black hole in the Milky Way’s nucleus. They are tangent to each other, touching at the galactic center to form a squat hourglass shape. The entire structure looks like the number 8 or a sideways infinity symbol. Gamma rays are the bad boys of the electromagnetic spectrum — the highest-energy photons in the universe. To review high school physics, a photon’s energy is a function of its waves’ lengths. Radiation whose waves are a mile apart (radio waves) are weak and benign; visible light has microscopically close-together waves; X-rays, and especially gamma rays, are crammed together with the maximum number of wave crests passing a given point per second. Because of this, gamma rays do not reliably reflect off objects the way visible light does. Rather, they penetrate stuff. Their photons drill through human bodies at the speed of light, damaging chromosomes along the way. Fortunately, few gamma rays reach us here at Earth’s surface. Although the Sun creates copious gamma rays in its fusion furnace, they are absorbed and re-radiated as gentler forms of light as they squirm upward to the solar surface. What finally flies away from the Sun is a roughly 50-50 mixture of heat and visible light and virtually no X-rays or gamma rays at all. Other stars don’t emit them either, and, in any case, Earth’s atmosphere blocks them. The only gamma rays flying near us come from distant violent events like supernovae. This is why a dense gamma-ray swarm at our galaxy’s center is so puzzling. It’s the unmistakable sign of extreme violence. And yet, these days, the Milky Way’s core is about as energetic as a steamy July lunchtime in New Orleans. These bubbles are sharp-edged, well-defined, and nothing short of enormous. The top and bottom of the “figure 8” extends 25,000 light-years above the galactic plane and the same distance beneath it. From our sideways viewpoint 26,000 light-years from the Milky Way’s center, the hourglass stands a whopping 45° above and below the galactic core, in the constellation Sagittarius. It takes up half of our southern sky. Theorists need to explain more than just what could have produced this kind of extreme energy, which is equivalent to 100,000 exploding supernovae. They must also explain the off-center nature of the bubbles because each seemingly surrounds nothingness. Jon Morse, director of the astrophysics division at NASA, summed up the discovery at a press conference: “It shows, once again, that the universe is full of surprises.” This gargantuan hourglass — which researchers are starting to call the Fermi Bubbles, in honor of the orbiting gamma-ray telescope launched in 2008 that found them — is now regarded as an entirely new type of astronomical object in the known universe. Trying to come up with some explanation for our galaxy blowing bubbles at temperatures of 7 million degrees Fahrenheit (3.9 million degrees Celsius), many astrophysicists have expressed a gratifying unanimity: “We have no idea.” Others, starting perforce from square one, have posited a couple of vague possible causes. The first theory is that, perhaps a few million years ago, a burst of star formation at the galactic center created numerous massive stars, all with high-speed winds of high-energy particles. Because this alone could not begin to explain the super-high energy within the bubbles, that theory further imagines that many of these stars blew up into supernovae simultaneously. Don’t like that one? Neither do I. So let’s go to the second possible explanation, which is that the 4-million-solar-mass black hole at our galaxy’s center had a brief feasting frenzy when much captured material was accelerated within its event horizon. Then, perhaps, that black hole could have developed something it does not presently have: twin jets of outrushing material. We see such jets exploding from the supermassive black holes in a few other galaxies (see M87, number 25 on our list, for example). These jets could have possibly deposited energetic material above and below the galactic plane, although how these bubbles then emanated from those positions is anyone’s guess. The ultimate answer could be even stranger. Might these be the long-sought signs of dark matter? Could dark matter be meeting its opposite entity (whatever that is) in total annihilation, the way matter and antimatter do? More likely, however, is that this is something else entirely, some new phenom that will actually get in the way of the dark matter hunt. As Douglas Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who first discovered the structure, put it, “It just confuses everything.” IT'S GAMMA TIME. Software processing of Fermi Gamma-ray Space Telescope data revealed the giant gamma-ray bubbles extending 25,000 light-years above and below our galaxy’s center. Many theories exist to explain their existence, but many scientists state: “We have no idea.” NASA/DOE/Fermi LAT/D. Finkbeiner, et al. astronomy.com/magazine/weirdest-objects/2015/12/1-fermi-bubbles?utm_source=asytwitter&utm_medium=social&utm_campaign=asytwitter
|
|
|
Post by auntym on Oct 12, 2021 23:28:04 GMT -6
www.newscientist.com/article/2293298-something-strange-is-sending-radio-waves-from-the-centre-of-the-galaxy/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1634082121Something strange is sending radio waves from the centre of the galaxySPACE 12 October 2021 By Leah Crane / www.newscientist.com/author/leah-crane/Illustration of radio waves coming from the galactic centre / Sebastian Zentilomo Strange radio signals are coming from the direction of the centre of the galaxy and we aren’t sure what is emitting them. They turn on and off seemingly at random, and their source must be unlike anything else we have seen before. The source of this radiation has been nicknamed “Andy’s object” after Ziteng Wang at the University of Sydney in Australia, who goes by the name Andy and first discovered the radio waves. He and his colleagues spotted the emissions six times in 2020 using the Australian Square Kilometre Array Pathfinder radio telescope. They made further observations with the MeerKAT radio telescope in South Africa. The researchers found that the object occasionally flared for up to a few weeks, but was dark most of the time. When it finally lit up again in February this year, several months after the initial detection, they pointed some of the most powerful non-radio telescopes we have at it and saw nothing. “We’ve looked at every other wavelength we can, all the way from the infrared to optical to X-rays, and we see nothing, so it doesn’t seem to be consistent with any kind of star that we understand,” says David Kaplan at the University of Wisconsin-Milwaukee, who was part of the research team. The fact that it wasn’t visible in any other wavelengths ruled out several possible explanations for this object, including normal stars and magnetars, which are neutron stars with powerful magnetic fields. Whatever Andy’s object is, the polarisation of the radio waves coming from it indicates that it probably has a strong magnetic field. During flares, its brightness varied by up to a factor of 100, and those flares faded extraordinarily quickly – as fast as a single day – facts that suggest the object is small. But no astronomical body we know of fits all of those strange traits. “It’s an interesting object that has confounded any attempt we have to explain it,” says Kaplan. “It could turn out to be part of a known class of objects, just a weird example, but that’ll push the boundaries of how we think those classes behave.” www.newscientist.com/article/2293298-something-strange-is-sending-radio-waves-from-the-centre-of-the-galaxy/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1634082121
|
|
|
Post by auntym on Dec 30, 2022 11:36:13 GMT -6
www.unknowncountry.com/headline-news/ghostly-glow-from-an-unknown-source-in-the-milky-way-may-reveal-a-previously-unidentified-galactic-component/Ghostly Glow from an Unknown Source in the Milky Way May Reveal a Previously Unidentified Galactic Component
December 29, 2022 New observations from the Hubble Space Telescope and the New Horizons spacecraft have unveiled the presence of a mysterious glow that permeates the solar system. This unexplained glow was discovered by the SKYSURF survey, an effort to catalogue the various sources of light within the solar system that can interfere with the observations being made by observatories such as the HST and the James Webb Space Telescope; using 200,000 images captured by Hubble, the survey created a model of the sky that eliminated all known sources of light emanating from local bodies, such as planets, moons, asteroids and comets, and then extended the same process to the stars and galaxies that are beyond the solar system. After eliminating these sources of light and accounting for a phenomenon known as “zodiacal light”—the sunlight that reflects off of the dust of the inner solar system—the survey team found that there was still a small amount of glow being emitted from an unidentified source. This glow is extremely faint—described by the SKYSURF team as being the equivalent of about 10 fireflies spread across the sky when seen from Earth—but still permeates the space throughout the solar system. The survey then turned to data gathered by the New Horizons interplanetary space probe to determine just how far outside the solar system this mysterious glow extends: from its far-flung vantage point far outside Pluto’s orbit, New Horizons detected the same glow, but at a drastically reduced intensity, indicating that this unaccounted-for light is a phenomenon particular to the solar system itself. “Because our measurement of residual light is higher than New Horizons we think it is a local phenomenon that is not from far outside the solar system,” explained Tim Carleton, one of the co-authors of the new study. “It may be a new element to the contents of the solar system that has been hypothesized but not quantitatively measured until now.” Although it is too early to make a proper determination, the survey team hypothesizes that this glow may be coming from a cloud of dust that surrounds the inner solar system, the remnants of material cast off by comets as they begin to heat up as they enter the inner solar system; however, this doesn’t explain why New Horizons saw the same, albeit less intense, glow. www.unknowncountry.com/headline-news/ghostly-glow-from-an-unknown-source-in-the-milky-way-may-reveal-a-previously-unidentified-galactic-component/
|
|
|
Post by auntym on Jul 10, 2023 15:25:01 GMT -6
www.nasa.gov/feature/goddard/2023/new-3d-visualization-highlights-5000-galaxies-revealed-by-webbJul 10, 2023 New 3D Visualization Highlights 5,000 Galaxies Revealed by WebbThis video, a scientific visualization of the galaxies captured as a part of the CEERS (Cosmic Evolution Early Release Science) Survey, showcases a large undertaking by NASA’s James Webb Space Telescope. It flies by thousands of galaxies, starting with those nearby and ending with less-developed galaxies in the very distant universe, including one never seen before Webb.This 3D visualization portrays about 5,000 galaxies within a small portion of the CEERS (Cosmic Evolution Early Release Science) Survey, which gathered data from a region known as the Extended Groth Strip. As the camera flies away from our viewpoint, each second amounts to traveling 200 million light-years into the data set, and seeing 200 million years further into the past. The appearances of the galaxies change, reflecting the fact that more distant objects are seen at earlier times in the universe, when galaxies were less developed. The video ends at Maisie’s Galaxy, which formed only 390 million years after the big bang, or about 13.4 billion years ago. Music: Spring Morning, Maarten Schellekens CC BY-NC 4.0 Credits: Visualization: Frank Summers (STScI), Greg Bacon (STScI), Joseph DePasquale (STScI), Leah Hustak (STScI), Joseph Olmsted (STScI), Alyssa Pagan (STScI) Download the video at Space Telescope Science Institute. The area highlighted in this visualization is a small part of the Extended Groth Strip, a region between the Ursa Major and Boötes constellations originally observed by the Hubble Space Telescope between 2004 and 2005. While this vast region contains about 100,000 galaxies, the visualization focuses on approximately 5,000 – with the nearest and more complex galaxies, shown in the beginning, located within a few billion light-years of Earth. As the visualization proceeds, showing galaxies farther away from Earth, we see different stages of the universe’s history and evolution. The visualization’s farthest galaxy, known as Maisie’s Galaxy, is a target of great interest to astronomers. It formed about 390 million years after the big bang, or about 13.4 billion years ago. It’s not only one of the first bright, extremely distant galaxies found by Webb, but it’s also an example of an early galaxy that only Webb could see. This is because Webb’s instruments can capture the light from these early galaxies, which has been shifted to infrared wavelengths by the expansion of the universe. “This observatory just opens up this entire period of time for us to study,” said Rebecca Larson of the Rochester Institute of Technology in Rochester, New York, one of the survey’s investigators. “We couldn’t study galaxies like Maisie’s before because we couldn’t see them. Now, not only are we able to find them in our images, we’re able to find out what they’re made of and if they differ from the galaxies that we see close by.” Steven Finkelstein of the University of Texas at Austin, principal investigator of the CEERS program, continued, “This observation exceeded our expectations. The sheer number of galaxies that we’re finding in the early universe is at the upper end of all predictions.” The observatory’s ability to conduct surveys like these provides a demonstration of Webb’s instruments for astronomers to reference for future observations. This visualization not only shows just how far Webb can observe, but also how much it builds off the accomplishments of Hubble. In many cases, Hubble’s observations, along with Webb’s data from the CEERS Survey, enabled researchers to determine which galaxies were truly far away – the early-universe galaxies of interest – and which were nearby, but so dusty that their visible light was obscured. With these observations, the next goal for researchers is to learn about the formation of stars in these early galaxies. “We’re used to thinking of galaxies as smoothly growing,” Finkelstein remarked. “But maybe these stars are forming like firecrackers. Are these galaxies forming more stars than expected? Are the stars they’re making more massive than we expect? These data have given us the information to ask these questions. Now, we need more data to get those answers.” The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency. www.nasa.gov/feature/goddard/2023/new-3d-visualization-highlights-5000-galaxies-revealed-by-webb
|
|
|
Post by auntym on Nov 30, 2023 18:07:36 GMT -6
www.space.com/andromeda-galaxy-november-2023?utm_source=twitter.com&utm_medium=social&utm_campaign=socialflow&utm_content=space.comOur neighbor the Andromeda Galaxy shines overhead this week. Here's how to see itBy Joe Rao / www.space.com/author/joe-rao11-30-2023 Located at a distance of 2.5 million light-years, here is the most distant object that can be seen with the unaided eye.The Andromeda Galaxy. (Image credit: Alan Dyer/VW Pics/Universal Images Group via Getty Images) "In 1976, Janet and I signed up for an 'astronomy cruise' to Bermuda. We were on deck one night where Fred Hess, a planetarium expert, pointed out the star patterns visible to the naked eye. Janet used her binoculars to look at the objects described, and the high point came when we saw the Andromeda Galaxy for the first time. If the cruise had ended at that point, we would have had our money's worth."
— Isaac Asimov, from "In Joy Still Felt" (Doubleday & Company, 1980)
There was a good reason why the famed science writer Isaac Asimov and his wife Janet were jubilant on that night at sea. For they had just had their very first look at the most distant object that can be glimpsed with the unaided eye: the Andromeda Galaxy.And this week, with the bright moon having left our evening sky, you too will have a chance to see this most amazing of deep sky objects, which will be passing almost directly overhead between 7:30 and 8 p.m. local time.To find the Andromeda Galaxy, first locate the Great Square of Pegasus — a landmark of the autumn sky. Then, focus binoculars on the bright star Alpheratz, which is at the upper left corner of the Square. Then move straight across to the east (left) and get the star Mirach (in Andromeda) in your field of view. From there, move slowly up to a fairly bright star above Mirach and continue to run up in the same direction until you'll find the "little cloud" described by Al-Sufi, more than a millennium ago. Night sky, November 2023: What you can see tonight [maps] www.space.com/16149-night-sky.htmlThat will be your stopping place, for you will have found the Andromeda Galaxy. If you aren't familiar with these stars or the Pegasus constellation, you could always use a stargazing app to help you find the Andromeda Galaxy — but put the phone away as soon as you've located it to let your eyes adjust to the dark night sky to ensure they can take in as much light from this distant city of stars as possible. Recall that the Asimov's had the advantage of being located on shipboard in the middle of the Atlantic when they made their Andromeda Galaxy sighting; not much concern about light pollution out there! But in order for you to see it requires good eyesight and a dark, crystal-clear night with no street or house lighting nearby. With the unaided eye it appears as nothing more than an indefinite, mysterious glow; a diffuse elongated cloud perhaps two or three times the apparent width of the moon. CONTINUE READING: www.space.com/andromeda-galaxy-november-2023?utm_source=twitter.com&utm_medium=social&utm_campaign=socialflow&utm_content=space.com
|
|
|
Post by auntym on Apr 16, 2024 17:23:33 GMT -6
If you're ever lost in space...this is the map to get you back home
|
|