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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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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A team of astronomers is proposing that huge spiral patterns seen around some newborn stars, merely a few million years old (about one percent our sun's age), may be evidence for the presence of giant, unseen planets. This idea not only opens the door to a new method of planet detection, but also could offer a look into the early formative years of planet birth. Though astronomers have cataloged thousands of planets orbiting other stars, the very earliest stages of planet formation are elusive because nascent planets are born and embedded inside vast, pancake-shaped disks of dust and gas encircling newborn stars. The conclusion that planets may betray their presence by mo…
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Astronomers are conducting extensive observations to estimate how many planets in our Milky Way galaxy might be potential abodes for life. These are collectively called "Earth-like" – in other words, Earth-sized worlds that are at the right distances from their stars for moderate temperatures to nurture the origin of life. The search for extraterrestrial intelligent life in the universe (SETI) is based on the hypothesis that some fraction of worlds, where life originates, go on to evolve intelligent technological civilizations. Until we ever find such evidence, Earth is the only known abode of life in the universe. But the universe is not only vastly big, it has a vast fu…
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Scientists using NASA's Hubble Space Telescope have produced new global maps of Jupiter – the first in a series of annual portraits of the solar system's outer planets from the Outer Planet Atmospheres Legacy program (OPAL). The two Jupiter maps, representing nearly back-to-back rotations of the planet on Jan. 19, 2015, show the movements of the clouds and make it possible to determine the speeds of Jupiter's winds. The Hubble observations confirm that the Great Red Spot continues to shrink and become more circular. In addition, an unusual wispy filament is seen, spanning almost the entire width of the vortex. These findings are described in a new paper published online i…
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Though astronomers have discovered thousands of planets orbiting other stars, very little is known about how they are born. The conventional wisdom is that planets coagulate inside a vast disk of gas and dust encircling newborn stars. But the details of the process are not well understood because it takes millions of years to happen as the disk undergoes numerous changes until it finally dissipates. The young, nearby star AU Microscopii (AU Mic) is an ideal candidate to get a snapshot of planet birthing because the disk is tilted nearly edge on to our view from Earth. This very oblique perspective offers an opportunity to see structure in the disk that otherwise might…
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Not long before the dawn of recorded human history, our distant ancestors would have witnessed what appeared to be a bright new star briefly blazing in the northern sky, rivaling the glow of our moon. In fact, it was the titanic detonation of a bloated star much more massive than our sun. Now, thousands of years later, the expanding remnant of that blast can be seen as the Cygnus Loop, a donut-shaped nebula that is six times the apparent diameter of the full moon. The Hubble Space Telescope was used to zoom into a small portion of that remnant, called the Veil Nebula. Hubble resolves tangled rope-like filaments of glowing gases. Supernovae enrich space with heavier elemen…
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Astronomers have discovered a rare beast of a galaxy cluster whose heart is bursting with new stars. The unexpected find, made with the help of NASA's Spitzer and Hubble space telescopes, suggests that behemoth galaxies at the cores of these massive clusters can grow significantly by feeding on gas stolen from other galaxies. The cluster in the new study, referred to by astronomers as SpARCS1049+56, has at least 27 galaxy members, and a combined mass equal to nearly 400 trillion suns. It is located 9.8 billion light-years away in the Ursa Major constellation. The object was initially discovered using Spitzer and the Canada-France-Hawaii Telescope, and confirmed using the …
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Astronomers at the University of California at Irvine (UCI) and the Space Telescope Science Institute have made the most accurate statistical estimate of the number of faint, small galaxies that existed only 500 million years after the big bang. This was culled from an analysis of the deepest Hubble Space Telescope sky survey, CANDELS (Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey). Previously, studies using Caltech's CIBER (the Cosmic Infrared Background Experiment) rocket-borne instrument and NASA's Spitzer Space Telescope images confirmed the presence of "intra-halo light" from stars distributed outside of galaxies. The Hubble data found a new componen…
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All stars are not created equal. They can vary in mass by over a factor of 1,000. Our sun is classified as a diminutive yellow dwarf. What's more, stars are not born in isolation, but inside giant molecular clouds of hydrogen. The question has been: what fraction of stars precipitate out of these clouds into clusters that contain blue giants, yellow dwarfs, and red dwarfs? It's like asking if all automobile manufacturers fabricate the same proportion of trucks, SUVs, sedans, and subcompacts. The best way to address the question is not to look around our Milky Way – which we are inside – but far out into space to the neighboring Andromeda galaxy, 2.5 million light-years aw…
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Quasars are the light fantastic. These brilliant cores of active galaxies blaze with the radiance of a hundred billion stars compressed into a region of space not much larger than our solar system. Supermassive black holes, with millions or billions of times the mass of our sun, are the only imaginable powerhouse behind these tsunamis of raw energy. Hubble Space Telescope astronomers set their sights on the nearest quasar to Earth, Markarian 231, located 581 million light-years away. Black holes – even supermassive ones – are too compact to be resolved by any present-day telescope. So, astronomers did the next best thing, measure all the light from a disk of infalling m…
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A team of astronomers, including half a dozen from the Space Telescope Science Institute (STScI) in Baltimore, Maryland, have used the Gemini Observatory's new Gemini Planet Imager to find the most solar system-like planet ever directly imaged around another star. The planet, known as 51 Eridani b, is about two times the mass of Jupiter and orbits its host star at about 13 times the Earth-sun distance (equivalent to being between Saturn and Uranus in our solar system). The planet is located about 100 light-years away from Earth. The Gemini data provide scientists with the strongest-ever spectroscopic detection of methane in the atmosphere of an extrasolar planet, adding t…
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What happens when you find something in the wrong place at the wrong time? That's a question astronomers have been trying to answer after finding several exploding stars outside the cozy confines of galaxies, where most stars reside. These wayward supernovae also have puzzled astronomers because they exploded billions of years before their predicted detonations. Astronomers using archived observations from several telescopes, including the Hubble Space Telescope, have developed a theory for where these doomed stars come from and how they arrived at their current homes. According to their scenario, the supernovae were once stars in double-star systems that wandered too c…
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