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 astronomer Edwin Hubble discovered nearly 100 years ago that the universe was uniformly expanding in all directions, the finding was a big surprise. Then, in the mid-1990s, another shocker occurred: astronomers found that the expansion rate was accelerating perhaps due to a repulsive property called "dark energy." Now, the latest measurements of our runaway universe suggest that it is expanding faster than astronomers thought. The consequences could be very significant for our understanding of the shadowy contents of our unruly universe. It may mean that dark energy is shoving galaxies away from each other with even greater – or growing – strength. Or, the early cosm…
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Using data from three of NASA's Great Observatories (the Hubble Space Telescope, Chandra X-ray Observatory, and Spitzer Space Telescope), scientists have found the best evidence to date that supermassive black holes in the early universe were produced by the direct collapse of a gas cloud. If confirmed, this result could lead to new insight into how black holes were formed and grew billions of years ago. This artist's illustration depicts a possible "seed" for the formation of a supermassive black hole. The inset boxes contain Chandra (top) and Hubble (bottom) images of one of two candidate seeds, where the properties in the data matched those predicted by sophisticated m…
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On May 12, 2016, astronomers using NASA's Hubble Space Telescope captured this striking image of Mars, when the planet was 50 million miles from Earth. The photo reveals details as small as 20 miles to 30 miles across. This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth. Mars also will be 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth. View the full article
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For thousands of years, humans have recorded sightings of mysterious comets sweeping across the nighttime skies. These celestial wanderers, "snowballs" of dust and ice, are swift-moving visitors from the cold depths of space. Some of them periodically visit the inner solar system during their journeys around the sun. Astronomers using NASA's Hubble Space Telescope captured images of Comet 252P/LINEAR just after it swept by Earth on March 21. The visit was one of the closest encounters between a comet and our planet. The comet traveled within 3.3 million miles of Earth, or about 14 times the distance between our planet and the moon. The images reveal a narrow, well-defin…
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Makemake is one of several dwarf planets that reside in the frigid outer realm of our solar system called the Kuiper Belt, a "junkyard" of countless icy bodies left over from our solar system's formation. After discovering Makemake in 2005, astronomers had searched several times for a companion orbiting the icy world. Now, the Hubble Space Telescope has uncovered a tiny moon around Makemake that is estimated to be 100 miles wide. Nicknamed MK 2, the moon is more than 1,300 times fainter than Makemake, which is 870 miles across. MK 2 is 13,000 miles away from the dwarf planet. View the full article
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Twenty-six candles grace NASA's Hubble Space Telescope's birthday cake this year, and now one giant space "balloon" will add to the festivities. Just in time for the 26th anniversary of Hubble's launch on April 24, 1990, the telescope has photographed an enormous, balloon-like bubble being blown into space by a super-hot, massive star. Astronomers trained the iconic telescope on this colorful feature, called the Bubble Nebula, or NGC 7635. The bubble is 7 light-years across – about one-and-a-half times the distance from our sun to its nearest stellar neighbor, Alpha Centauri. The Bubble Nebula lies 7,100 light-years from Earth in the constellation Cassiopeia. View …
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Imagine driving through a small town containing modest-sized buildings and seeing a 100-story skyscraper. Astronomers found the equivalent monstrosity in space: a near-record supermassive black hole that weighs 17 billion suns and lives in a cosmic backwater community of a few galaxies. Until now, extremely massive black holes have been found at the cores of very large galaxies in regions of the universe packed with other large galaxies. This is not just coincidence. Like a cosmic Pac-Man, a monster black hole gobbles smaller black holes when two galaxies collide. This game of bumper cars is common in large galaxy clusters. In fact, the current black hole record holder ti…
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Hubble's infrared vision pierced the dusty heart of our Milky Way galaxy to reveal more than half a million stars at its core. Except for a few blue, foreground stars, the stars are part of the Milky Way's nuclear star cluster, the most massive and densest stellar cluster in our galaxy. Located 27,000 light-years away, this region is so packed with stars, it is equivalent to having a million suns crammed into the volume of space between us and our closest stellar neighbor, Alpha Centauri, 4.3 light-years away. At the very hub of our galaxy, this star cluster surrounds the Milky Way's central supermassive black hole, which is about 4 million times the mass of our sun. …
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NASA has selected 36 fellows for its prestigious Einstein, Hubble, and Sagan Fellowships. Each postdoctoral fellowship provides three years of support to awardees to pursue independent research in astronomy and astrophysics. The new fellows will begin their programs in the fall of 2016 at a host university or research center of their choosing in the United States. View the full article
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An international team of astronomers using the ultraviolet capabilities of NASA's Hubble Space Telescope has identified nine monster stars with masses over 100 times the mass of the sun in the star cluster R136. This makes for the largest sample of very massive stars identified to date. The results, which will be published in the Monthly Notices of the Royal Astronomical Society, raise many new questions about the formation of massive stars. R136 is only a few light-years across and is located in the Tarantula Nebula within the Large Magellanic Cloud, about 170,000 light-years away from Earth. The young cluster hosts many extremely massive, hot, and luminous stars whose e…
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To learn more about galaxy clusters, including how they grow via collisions, astronomers have used some of the world's most powerful telescopes, looking at different types of light. They have focused long observations with these telescopes on a half-dozen galaxy clusters. The name for the galaxy cluster project is the "Frontier Fields." Two of these Frontier Fields galaxy clusters, MACS J0416.1-2403 (abbreviated MACS J0416) in the right panel and MACS J0717.5+3745 (MACS J0717 for short) in the left panel, are featured here in a pair of multiwavelength images. Located about 4.3 billion light-years from Earth, MACS J0416 is a pair of colliding galaxy clusters that will ev…
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NASA's Hubble Space Telescope is an amazing time machine; by looking back through space, astronomers actually look back through time. Now, by pushing Hubble to its limits, an international team of astronomers has shattered the cosmic distance record by viewing the farthest galaxy ever seen. Named GN-z11, this surprisingly bright, infant galaxy is seen as it was 13.4 billion years in the past. The astronomers saw it as it existed just 400 million years after the big bang, when the universe was only three percent of its current age. At a spectroscopically confirmed redshift of 11.1, the galaxy is even farther away than originally thought. It existed only 200 million to 300 …
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Though nearly 2,000 planets have been found around other stars, the light from only a handful of them has ever been collected by the world's most powerful telescopes. Ironically, a lot of them are detected by the shadows they cast, as they pass in front of their parent stars. Follow-up observations measure the planet's feeble, but telltale, gravitational tug on its parent star. Now, Hubble Space Telescope astronomers have been able to pick up the faint infrared glow of a giant planet located 170 light-years away from Earth. Not only is it glowing, but also rhythmically flickering as the planet spins on its axis like a top. The interpretation is that the subtle changes in …
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After years of preparatory studies, NASA is formally starting an astrophysics mission designed to help unlock the secrets of the universe the Wide-Field Infrared Survey Telescope (WFIRST). WFIRST will image large regions of the sky in near-infrared light to answer fundamental questions about dark energy and the structure and evolution of the universe. It will also find and characterize planets beyond our solar system, and as a general-purpose observatory, revolutionize many other astrophysical topics. WFIRST will have a mirror the same size as Hubble's, but it will have a 100 times wider view of space. Slated for launch in the mid-2020s, it will complement the capabilitie…
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The old adage "what goes up must come down" even applies to an immense cloud of hydrogen gas outside our Milky Way galaxy. First discovered in the 1960s, the comet-shaped cloud is 11,000 light-years long and 2,500 light-years across. If the cloud could be seen in visible light, it would span the sky with an apparent diameter 30 times greater than the size of the full moon. The cloud, which is invisible at optical wavelengths, is plummeting toward our galaxy at nearly 700,000 miles per hour. Hubble was used to measure the chemical composition of the cloud as a means of assessing where it came from. Hubble astronomers were surprised to find that the cloud, which is largely …
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Some of the Milky Way's "celebrity stars" — opulent, attention-getting, and short-lived — can be found in this Hubble Space Telescope image of the glittering star cluster called Trumpler 14. It is located 8,000 light-years away in the Carina Nebula, a huge star-formation region in our galaxy. Because the cluster is only 500,000 years old, it has one of the highest concentrations of massive, luminous stars in the entire Milky Way. Like some Hollywood celebrities, the stars will go out in a flash. Within just a few million years they will burn out and explode as supernovae. But the story's not over. The blast waves will trigger the formation of a new generation of stars ins…
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Astronomers have made the most detailed study yet of an extremely massive young galaxy cluster using three of NASA's Great Observatories. This multiwavelength image shows this galaxy cluster, called IDCS J1426.5+3508 (IDCS 1426 for short), in X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light from the Spitzer Space Telescope in red. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications for understanding how these megastructures formed and evolved early in the universe. Astronome…
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Eta Carinae, the most luminous and massive stellar system located within 10,000 light-years of Earth, is best known for an enormous eruption seen in the mid-19th century that hurled an amount of material at least 10 times the sun's mass into space. Still shrouded by this expanding veil of gas and dust, Eta Carinae is the only object of its kind known in our galaxy. Now a study using archival data from NASA's Spitzer and Hubble space telescopes has found five similar objects in other galaxies for the first time. View the full article
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Just about anything is possible in our remarkable universe, and it often competes with the imaginings of science fiction writers and filmmakers. Hubble's latest contribution is a striking photo of what looks like a double-bladed lightsaber straight out of the Star Wars films. In the center of the image, partially obscured by a dark, Jedi-like cloak of dust, a newborn star shoots twin jets out into space as a sort of birth announcement to the universe. Gas from a surrounding disk rains down onto the dust-obscured protostar and engorges it. The material is superheated and shoots outward from the star in opposite directions along an uncluttered escape route – the star's rota…
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Hubble has captured an image of the first-ever predicted supernova explosion. The reappearance of the supernova dubbed "Refsdal" was calculated by different mass models of a galaxy cluster whose immense gravity is warping the supernova's light as the light travels toward Earth. The supernova was previously seen in November 2014 behind the galaxy cluster MACS J1149.5+2223, part of Hubble's Frontier Fields program. Astronomers spotted four separate images of the supernova in a rare arrangement known as an Einstein Cross. This pattern was seen around a galaxy within MACS J1149.5+2223. While the light from the cluster has taken about five billion years to reach us, the supern…
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A survey of Jupiter-sized exoplanets conducted with the Hubble and Spitzer space telescopes has solved a long-standing mystery – why some of these worlds seem to have less water than expected. Astronomers have found that planets called hot Jupiters (which orbit very close to their stars) that are apparently cloud-free show strong signs of water. However, atmospheres of other planets with faint water signals also contained clouds and haze – both of which are known to hide water from view. The findings show that planetary atmospheres are much more diverse than expected. Also, the results offer insights into the wide range of planetary atmospheres in our galaxy and how plane…
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For the past 60 years, astronomers have been puzzled by an unusual type of star that looks hotter and bluer than it should for its age. It has been dubbed a "blue straggler" because it seems to lag behind the evolution of neighboring stars. Blue stragglers dwell inside ancient star clusters that should have stopped making youthful and short-lived blue stars billions of years ago. The most popular explanation among several competing theories is that an aging star spills material onto a smaller companion star. The small star bulks up on mass to become hotter and bluer, while the aging companion burns out and collapses to a white dwarf – a burned out cinder. To test this the…
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Hunting for faraway galaxies that existed long, long ago is like a fishing trip for astronomers. So far only the "big fish" have been found, bright galaxies that existed just a few hundred million years after the big bang. Now, using the Hubble and Spitzer space telescopes, astronomers have caught a "smaller fish," a very compact and faint early galaxy that was forming 400 million years after the big bang, which happened 13.8 billion years ago. As there are many smaller fish than big fish in the sea, the new finding is evidence for an underlying population of dim galaxies that must have been common in the early universe. Hubble's upcoming successor, the James Webb Space…
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About 13 billion years ago, long before our sun formed, the construction of our Milky Way galaxy was just beginning. Young, mostly sun-like stars in the core, or central bulge, provided the building blocks for the galaxy's foundation. Many of these building-block stars have long since burned out, and are now just dying embers. But contained within these dead stars, called white dwarfs, is the early history of our galaxy, providing clues on how it came to be. Finding these stellar relics, however, is a daunting task. Astronomers have had a difficult time picking out these dim objects from among the crowd of bright stars that fill the space between us and the core. Using …
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Dr. Kenneth R. Sembach has been appointed director of the Space Telescope Science Institute (STScI) in Baltimore. STScI is operated by the Association of Universities for Research in Astronomy (AURA) under contract with NASA to conduct the science program of the Hubble Space Telescope and to develop the Science and Mission Operations Center for the James Webb Space Telescope. The Institute also operates the Barbara A. Mikulski Archive for Space Telescopes for NASA. Sembach succeeds Dr. Matt Mountain, who had served as STScI director since 2005. View the full article
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