Astronomy and Stars
Discussions about astronomy and stars. As we look further out what can we find in the universe beyond Earth's atmosphere?
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When you want to know the size of a room, you use a measuring tape to calculate its dimensions. But you can’t use a tape measure to cover the inconceivably vast distances in space. And, until now, astronomers did not have an equally precise method to accurately measure distances to some of the oldest objects in our universe – ancient swarms of stars outside the disk of our galaxy called globular clusters. Estimated distances to our Milky Way galaxy’s globular clusters were achieved by comparing the brightness and colors of stars to theoretical models and observations of local stars. But the accuracy of these estimates varies, with uncertainties hovering between 10 per…
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NASA has selected 24 new Fellows for its prestigious NASA Hubble Fellowship Program (NHFP). The program enables outstanding postdoctoral scientists to pursue independent research in any area of NASA Astrophysics, using theory, observation, experimentation, or instrument development. Each fellowship provides the awardee up to three years of support. View the full article
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Through a quirk of nature called “gravitational lensing,” a natural lens in space amplified a very distant star’s light. Astronomers using Hubble took advantage of this phenomenon to pinpoint the faraway star and set a new distance record for the farthest individual star ever seen. They also used the distant star to test one theory of dark matter, and to probe the make-up of a galaxy cluster. The team dubbed the star “Icarus,” after the Greek mythological character who flew too near the Sun on wings of feathers and wax that melted. Its official name is MACS J1149+2223 Lensed Star 1. View the full article
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Grand, majestic spiral galaxies like our Milky Way are hard to miss. Astronomers can spot these vast complexes because of their large, glowing centers and their signature winding arms of gas and dust, where thousands of glowing stars reside. But some galaxies aren't so distinctive. They are big, but they have so few stars for their size that they appear very faint and diffuse. In fact, they are so diffuse that they look like giant cotton balls. Observations by NASA's Hubble Space Telescope of one such galaxy have turned up an oddity that sets it apart from most other galaxies, even the diffuse-looking ones. It contains little, if any, dark matter, the underlying scaff…
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The universe is so huge that it's estimated that a star explodes as a supernova once every second. Astronomers capture a small fraction of these detonations because they are comparatively short-lived, like fireflies flickering on a summer evening. After skyrocketing to a sudden peak in brightness, a supernova can take weeks to slowly fade away. For the past decade astronomers have been befuddled by a more curious "flash-in-the-pan" that pops up and then disappears in just a few days, not weeks. It's called a Fast-Evolving Luminous Transient (FELT). Only a few FELTs have been seen in telescopic sky surveys because they are so brief. Then along came NASA's Kepler Space …
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In a cosmic tug-of-war between two dwarf galaxies orbiting the Milky Way, only NASA’s Hubble Space Telescope can see who’s winning. The players are the Large and Small Magellanic Clouds, and as they gravitationally tug at each other, one of them has pulled out a huge amount of gas from its companion. This shredded and fragmented gas, called the Leading Arm, is being devoured by the Milky Way and feeding new star birth in our galaxy. But which dwarf galaxy is doing the pulling, and whose gas is now being feasted upon? Scientists used Hubble’s ultraviolet vision to chemically analyze the gas in the Leading Arm and determine its origin. After years of debate, we now have th…
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The adventuring cinema archeologist Indiana Jones would be delighted to find a long-sought relic in his own backyard. Astronomers have gotten lucky enough to achieve such a quest. They identified a very rare and odd assemblage of stars that has remained essentially unchanged for the past 10 billion years. The diffuse stellar island provides valuable new insights into the origin and evolution of galaxies billions of years ago. As far as galaxy evolution goes, this object is clearly a case of “arrested development.” The galaxy, NGC 1277, started its life with a bang long ago, ferociously churning out stars 1,000 times faster than seen in our own Milky Way today. But it ab…
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Finding lots of dust around stars may not sound like anything astronomers would get excited about. The universe is a dusty place. But dust around a young star can be evidence that planet formation is taking place. This isn’t a new idea. In 1755, German Philosopher Immanuel Kant first proposed that planets formed around our Sun in a debris disk of gas and dust. Astronomers imagined that this process might take place around other stars. They had to wait until the early 1980s for the first observational evidence for a debris disk around any star to be uncovered. An edge-on debris disk was photographed around the southern star Beta Pictoris. Beta Pictoris remained the poste…
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Using Hubble and Spitzer space telescopes, scientists studied the “hot Saturn” called WASP-39b — a hot, bloated, Saturn-mass exoplanet located about 700 light-years from Earth. By dissecting starlight filtering through the planet’s atmosphere into its component colors, the team found clear evidence for a large amount of water vapor. In fact, WASP-39b has three times as much water as Saturn does. Although the researchers predicted they’d see water, they were surprised by how much they found. This suggests that the planet formed farther out from the star, where it was bombarded by a lot of icy material. Because WASP-39b has so much more water than Saturn, it must have forme…
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The good news: Astronomers have made the most precise measurement to date of the rate at which the universe is expanding since the big bang. The possibly unsettling news: This may mean that there is something unknown about the makeup of the universe. The new numbers remain at odds with independent measurements of the early universe's expansion. Is something unpredicted going on in the depths of space? Astronomers have come a long way since the early 1900s when they didn't have a clue that we lived in an expanding universe. Before this could be realized, astronomers needed an accurate celestial measuring stick to calculate distances to far-flung objects. At that time, f…
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Three billion miles away on the farthest known major planet in our solar system, an ominous, stinky, dark storm is shrinking out of existence as seen in pictures of Neptune taken by the Hubble Space Telescope. Immense dark storms on Neptune were first discovered in the late 1980s by the Voyager 2 spacecraft. Since then, only Hubble has tracked these elusive features that play a game of peek-a-boo over the years. Hubble found two dark storms that appeared in the mid-1990s and then vanished. This latest storm was first seen in 2015, but is now shrinking away. The dark spot material may be hydrogen sulfide, with the pungent smell of rotten eggs. View the full article
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Only 40 light-years away — a stone’s throw on the scale of our galaxy — several Earth-sized planets orbit the red dwarf star TRAPPIST-1. Four of the planets lie in the star’s habitable zone, a region at a distance from the star where liquid water, the key to life as we know it, could exist on the planets’ surfaces. Astronomers using NASA's Hubble Space Telescope have conducted the first spectroscopic survey of these worlds. Hubble reveals that at least three of the exoplanets do not seem to contain puffy, hydrogen-rich atmospheres similar to gaseous planets such as Neptune. This means the atmospheres may be more shallow and rich in heavier gases like those found in Eart…
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Using NASA's Hubble Space Telescope to peer deep into the vast stellar nursery called the Orion Nebula, astronomers searched for small, faint bodies. What they found was the largest population yet of brown dwarfs — objects that are more massive than planets but do not shine like stars. Researchers identified 17 brown dwarf companions to red dwarf stars, one brown dwarf pair, and one brown dwarf with a planetary companion. They also found three giant planets, including a binary system where two planets orbit each other in the absence of a parent star. This survey could only be done with Hubble’s exceptional resolution and infrared sensitivity. View the full article
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Every star has a story to tell. Study a star and it will give you information about its composition, age, and possibly even clues to where it first formed. The stars residing in the oldest structure of our Milky Way galaxy, the central bulge, offer insight into how our pinwheel-shaped island of myriad stars evolved over billions of years. Think of our Milky Way as a pancake-shaped structure with a big round dollop of butter in the middle — that would be our galaxy’s central hub. For many years, astronomers had a simple view of our Milky Way’s bulge as a quiescent place composed of old stars, the earliest homesteaders of our galaxy. A new analysis of about 10,000 normal …
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As powerful as NASA’s Hubble and Spitzer space telescopes are, they need a little help from nature in seeking out the farthest, and hence earliest galaxies that first appeared in the universe after the big bang. This help comes from a natural zoom lens in the universe, formed by the warping of space by intense gravitational fields. The most powerful “zoom lenses” out there are formed by very massive foreground clusters that bend space like a bowling ball rolling across a soft mattress. The lens boosts the brightness of distant background objects. The farthest candidates simply appear as red dots in Hubble photos because of their small size and great distance. However,…
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Supermassive black holes, weighing millions of times as much as our Sun, are gatherers not hunters. Embedded in the hearts of galaxies, they will lie dormant for a long time until the next meal happens to come along. The team of astronomers using observations from the Hubble Space Telescope, the Chandra X-ray Observatory, and as well as the W.M. Keck Observatory in Mauna Kea, Hawaii, and the Apache Point Observatory (APO) near Sunspot, New Mexico, zeroed in on a flickering black hole. A black hole in the center of galaxy SDSS J1354+1327, located about 800 million light-years away, appears to have consumed large amounts of gas while blasting off an outflow of high-ener…
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By combining the visible and infrared capabilities of the Hubble and Spitzer space telescopes, astronomers and visualization specialists from NASA's Universe of Learning program have created a spectacular, three-dimensional, fly-through movie of the magnificent Orion nebula, a nearby stellar nursery. Using actual scientific data along with Hollywood techniques, a team at the Space Telescope Science Institute in Baltimore, Maryland, and the Caltech/IPAC in Pasadena, California, has produced the best and most detailed multi-wavelength visualization yet of the Orion nebula. The three-minute movie allows viewers to glide through the picturesque star-forming region and experie…
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It's beginning to look a lot like the holiday season in this NASA Hubble Space Telescope image of a blizzard of stars, which resembles a swirling snowstorm in a snow globe. The stars are residents of the globular star cluster Messier 79, or M79, located 41,000 light-years from Earth, in the constellation Lepus. The cluster is also known as NGC 1904. View the full article
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Voices reverberating off mountains and the sound of footsteps bouncing off walls are examples of an echo. Echoes happen when sound waves ricochet off surfaces and return to the listener. Space has its own version of an echo. It’s not made with sound but with light, and occurs when light bounces off dust clouds. The Hubble telescope has just captured one of these cosmic echoes, called a “light echo,” in the nearby starburst galaxy M82, located 11.4 million light-years away. A movie assembled from more than two years’ worth of Hubble images reveals an expanding shell of light from a supernova explosion sweeping through interstellar space three years after the stellar …
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Photobombing asteroids from our solar system have snuck their way into this deep image of the universe taken by NASA’s Hubble Space Telescope. These asteroids are right around the corner in astronomical terms, residing roughly 160 million miles from Earth. Yet they’ve horned their way into this picture of thousands of galaxies scattered across space and time at inconceivably farther distances. View the full article
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Travelers to the nightside of exoplanet Kepler-13Ab should pack an umbrella because they will be pelted with precipitation. But it's not the kind of watery precipitation that falls on Earth. On this alien world, the precipitation is in the form of sunscreen. Ironically, the sunscreen (titanium dioxide) is not needed on this side of the planet because it never receives any sunlight. But bottling up some sunlight protection is a good idea if travelers plan on visiting the sizzling hot, permanent dayside, which always faces its star. Visitors won't find any desperately needed sunscreen on this part of the planet. Astronomers didn't detect the titanium dioxide directly. T…
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When some people get in the kitchen, they create a delicious meal but leave behind a chaotic mess of splattered food and dirty dishes. Cosmic cookery can be just as messy. While a star can create chemical elements as heavy as iron within its core, anything heavier needs a more powerful source like a stellar explosion or the collision of two neutron stars. Colliding neutron stars can yield gold, plutonium, and a variety of other elements. Theoretically, they also generate gravitational waves as they spiral together at breakneck speed before merging. The first gravitational wave signal from a neutron star merger was detected on August 17. It was accompanied by gamma rays …
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A solitary frozen traveler has been journeying for millions of years toward the heart of our planetary system. The wayward vagabond, a city-sized snowball of ice and dust called a comet, was gravitationally kicked out of the Oort Cloud, its frigid home at the outskirts of the solar system. This region is a vast comet storehouse, composed of icy leftover building blocks from the construction of the planets 4.6 billion years ago. The comet is so small, faint, and far away that it eluded detection. Finally, in May 2017, astronomers using the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in Hawaii spotted the solitary intruder at a whopping 1.5 billion …
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Astronomers categorize the minor bodies in the solar system according to their location and physical composition. Comets are a loose collection of ice and dust that fall in toward the Sun from beyond the orbits of the major planets, and grow long tails of dust and gas along the way. Asteroids are rocky or metallic and are relegated to a zone between Mars and Jupiter. But nature isn't that tidy. The Hubble Space Telescope photographed a pair of asteroids orbiting each other that have a tail of dust, which is definitely a comet-like feature. The odd object, called 2006 VW139/288P, is the first known binary asteroid that is also classified as a main-belt comet. Roughly 5,000…
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Don't go looking for the proverbial black cat eating licorice in a coal bin on the planet WASP-12b. Twice the size of any planet found in our solar system, the world is as black as fresh asphalt. Unlike other planets in its class, WASP-12b has the unique capability to trap at least 94 percent of the visible starlight falling into its atmosphere. The temperature of the atmosphere is a seething 4,600 degrees Fahrenheit, which prevents the formation of reflective clouds on the day side. The planet orbits so close to its host that it is tidally locked, which means that it keeps the same side always facing the star. The exoplanet isn't dining alone. Its host star is also …
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