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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Solar flares and associated eruptions can trigger auroras on Earth or, more ominously, damage satellites and power grids. Could flares on cool, red dwarf stars cause even more havoc to orbiting planets, even rendering them uninhabitable? To help answer that question, astronomers sought to find out how many flares such stars typically unleash. A new study of archival ultraviolet observations from the Galaxy Evolution Explorer (GALEX) spacecraft detected dozens of flares from red dwarf stars. Some flares were weaker than any previously detected. Since smaller flares tend to occur more frequently, these tiny flares might have big implications for planetary habitability. …
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Astronomers once thought that the family of planets that orbit our sun were typical of what would eventually be found around other stars: a grouping of small rocky planets like Earth huddled close to their parent star, and an outer family of monstrous gaseous planets like Jupiter and Saturn. But ever since the discovery of the first planet around another star (or exoplanet) the universe looks a bit more complicated — if not downright capricious. There is an entire class of exoplanets called "hot Jupiters." They formed like Jupiter did, in the frigid outer reaches of their planetary system, but then changed Zip code! They migrated inward to be so close to their star that…
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Every second a star somewhere out in the universe explodes as a supernova. But some super-massive stars go out with a whimper instead of a bang. When they do, they can collapse under the crushing tug of gravity and vanish out of sight, only to leave behind a black hole. The doomed star, named N6946-BH1, was 25 times as massive as our sun. It began to brighten weakly in 2009. But, by 2015, it appeared to have winked out of existence. By a careful process of elimination, based on observations by the Large Binocular Telescope and the Hubble and Spitzer space telescopes, the researchers eventually concluded that the star must have become a black hole. This may be the fate for…
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Beyond the orbit of Neptune lies a frigid, dark, vast frontier of countless icy bodies left over from the solar system's construction 4.6 billion years ago. This region, called the Kuiper Belt, was hypothesized by astronomer Gerard Kuiper in 1951. But it took another four decades for astronomers to confirm its existence. The largest bodies are called dwarf planets, with Pluto being the biggest member. Pluto is so big, in fact, that it was discovered 60 years before other Kuiper worlds were detected. Moons around dwarf planets are elusive, though. Pluto's moon Charon wasn't found until the mid-1970s. Now, astronomers have uncovered a moon around another dwarf planet by u…
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In the summer of the year 1054 AD, Chinese astronomers saw a new "guest star," that appeared six times brighter than Venus. So bright in fact, it could be seen during the daytime for several months. Halfway around the world, Native Americans made pictographs of a crescent moon with the bright star nearby that some think may also have been a record of the supernova. This "guest star" was forgotten about until 700 years later with the advent of telescopes. Astronomers saw a tentacle-like nebula in the place of the vanished star and called it the Crab Nebula. Today we know it as the expanding gaseous remnant from a star that self-detonated as a supernova, briefly shining a…
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Like the quirky characters in the upcoming film Guardians of the Galaxy Vol. 2, NASA's Hubble Space Telescope has some amazing superpowers, specifically when it comes to observing galaxies across time and space. One stunning example is galaxy cluster Abell 370, which contains a vast assortment of several hundred galaxies tied together by the mutual pull of gravity. That's a lot of galaxies to be guarding, and just in this one cluster! Photographed in a combination of visible and near-infrared light, the immense cluster is a rich mix of galaxy shapes. Entangled among the galaxies are mysterious-looking arcs of blue light. These are actually distorted images of remote galax…
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When the Hubble Space Telescope launched aboard the Space Shuttle Discovery on April 24, 1990, astronomers could only dream what they might see. Now, 27 years and more than a million observations later, the telescope delivers yet another magnificent view of the universe — this time, a striking pair of spiral galaxies much like our own Milky Way. These island cities of stars, which are approximately 55 million light-years away, give astronomers an idea of what our own galaxy would look like to an outside observer. The edge-on galaxy is called NGC 4302, and the tilted galaxy is NGC 4298. Although the pinwheel galaxies look quite different because they are angled at differen…
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When Galileo discovered Jupiter's moon Europa in 1610, along with three other satellites whirling around the giant planet, he could have barely imagined it was such a world of wonder. This revelation didn't happen until 1979, when NASA's Voyager 1 and 2 flew by Jupiter and found evidence that Europa's interior, encapsulated under a crust of ice, has been kept warm over billions of years. The warmer temperature is due to gravitational tidal forces that flex the moon's interior — like squeezing a rubber ball — keeping it warm. At the time, one mission scientist even speculated that the Voyagers might catch a snapshot of geysers on Europa. Such activity turned out to be …
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Named after the Roman king of the gods, the immense planet Jupiter is undoubtedly king of the solar system. Containing more mass than all the other planets combined, Jupiter's immense gravitational field deflects wayward comets that otherwise might slam into Earth, wreaking havoc. This dazzling Hubble Space Telescope photo of Jupiter was taken when it was comparatively close to Earth, at a distance of 415 million miles. Hubble reveals the intricate, detailed beauty of Jupiter's clouds as arranged into bands of different latitudes, known as tropical regions. These bands are produced by air flowing in different directions at various latitudes. Lighter colored areas, calle…
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Of all the varieties of exploding stars, the ones called Type Ia are perhaps the most intriguing. Their predictable brightness lets astronomers measure the expansion of the universe, which led to the discovery of dark energy. Yet the cause of these supernovae remains a mystery. Do they happen when two white dwarf stars collide? Or does a single white dwarf gorge on gases stolen from a companion star until bursting? If the second theory is true, the normal star should survive. Astronomers used NASA's Hubble Space Telescope to search the gauzy remains of a Type Ia supernova in a neighboring galaxy called the Large Magellanic Cloud. They found a sun-like star that showed s…
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NASA has selected 28 Fellows for its prestigious Einstein, Hubble, and Sagan fellowships. Each post-doctoral 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 2017 at a host university or research center of their choosing in the United States. View the full article
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Normally, hefty black holes anchor the centers of galaxies. So researchers were surprised to discover a supermassive black hole speeding through the galactic suburbs. Black holes cannot be observed directly, but they are the energy source at the heart of quasars — intense, compact gushers of radiation that can outshine an entire galaxy. NASA's Hubble Space Telescope made the discovery by finding a bright quasar located far from the center of the host galaxy. Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. What could pry this giant monster from its central home? The most plausible expl…
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In the 1400s, two power struggles were taking place quadrillions of miles apart. In England, two rival branches of the royal House of Plantagenet were battling each other for control of the country's throne. And, in a nebula far, far away, a cluster of stars was waging a real-life star wars, with the stellar members battling each other for supremacy in the Orion Nebula. The gravitational tussle ended with the system breaking apart and at least three stars being ejected in different directions. Astronomers spotted two of the speedy, wayward stars over the past few decades. They traced both stars back 540 years to the same location and suggested they were part of a now-de…
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About 6 million years ago, when our very remote ancestors began to evolve away from chimpanzees, our Milky Way galaxy's hefty black hole was enjoying a sumptuous feast. It gulped down a huge clump of interstellar hydrogen. Now, eons later, we see the result of the black hole feast. The black hole "burped" hot plasma that is now towering far above and below the plane of our galaxy. These invisible bubbles, weighing the equivalent of millions of suns, are called the Fermi Bubbles. Their energetic gamma-ray glow was first discovered in 2010 by NASA's Fermi Gamma-ray Space Telescope. (Enrico Fermi was an Italian physicist who created the world's first nuclear reactor.) As…
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Twenty years ago, astronauts on the second servicing mission to the Hubble Space Telescope installed the Space Telescope Imaging Spectrograph (STIS) aboard Hubble. This pioneering instrument combines a camera with a spectrograph, which provides a "fingerprint" of a celestial object's temperature, chemical composition, density, and motion. STIS also reveals changes in the evolving universe and leads the way in the field of high-contrast imaging. The versatile instrument is sensitive to a wide range of wavelengths of light, from ultraviolet through the optical and into the near-infrared. From studying black holes, monster stars, and the intergalactic medium, to analyzing th…
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In February 1987, on a mountaintop in Chile, telescope operator Oscar Duhalde stood outside the observatory at Las Campanas and looked up at the clear night sky. There, in a hazy-looking patch of brightness in the sky — the Large Magellanic Cloud (LMC), a neighboring galaxy - was a bright star he hadn't noticed before. That same night, Canadian astronomer Ian Shelton was at Las Campanas observing stars in the Large Magellanic Cloud. As Shelton was studying a photographic plate of the LMC later that night, he noticed a bright object that he initially thought was a defect in the plate. When he showed the plate to other astronomers at the observatory, he realized the objec…
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NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are located in an area called the habitable zone, where liquid water is most likely to thrive on a rocky planet. The system sets a new record for the greatest number of habitable zone planets found outside our solar system. Any of these seven planets could have liquid water, the key to life as we know it. The exoplanet system is called TRAPPIST-1 and is only 40 light-years away. Following up on the Spitzer discovery, NASA's Hubble Space Telescope has initiated the screening of four of the planets, including the three inside the habita…
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Astronomers have found the best evidence yet of the remains of a comet-like object scattered around a burned-out star. They used NASA's Hubble Space Telescope to detect the debris, which has polluted the atmosphere of a compact star known as a white dwarf. The icy object, which has been ripped apart, is similar to Halley's Comet in chemical composition, but it is 100,000 times more massive and has a much higher amount of water. It is also rich in the elements essential for life, including nitrogen, carbon, oxygen, and sulfur. These findings are evidence for a belt of comet-like bodies similar to our solar system's Kuiper Belt orbiting the white dwarf. This is the first ev…
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The Space Telescope Science Institute (STScI) in Baltimore, Maryland, has appointed Dr. Margaret Meixner and Dr. Marc Postman to the position of STScI Distinguished Astronomer. Distinguished Astronomer is the highest level of appointment on the tenure track at STScI and represents a rank commensurate with the highest level of professorial appointments at major universities. Meixner's promotion recognizes her long-term contributions to research and service at STScI. She has led international teams to study the life cycle of dust in the Magellanic Clouds using the Hubble, Spitzer and Herschel space telescopes. Postman is being recognized for his long-term contributions to…
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Since the dawn of civilization, we have gazed into the night sky and attempted to make sense of what we saw there, asking questions such as: Where do we come from? What is our place in the universe? And are we alone? As we ask those questions today and new technology expands our horizons further into space, our yearning for their answers only grows. Since its launch in 1990, NASA's Hubble Space Telescope has continued this quest for answers while orbiting Earth every 90 minutes. Hubble has not only made countless new astronomical discoveries, but also brought astronomy to the public eye, satisfying our curiosity, sparking our imaginations, and greatly impacting culture, s…
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Eerie mysteries in the universe can be betrayed by simple shadows. The wonder of a solar eclipse is produced by the moon's shadow, and over 1,000 planets around other stars have been cataloged by the shadow they cast when passing in front of their parent star. Astronomers were surprised to see a huge shadow sweeping across a disk of dust and gas encircling a nearby, young star. They have a bird's-eye view of the disk, because it is tilted face-on to Earth, and the shadow sweeps around the disk like the hands moving around a clock. But, unlike the hands of a clock, the shadow takes 16 years to make one rotation. Hubble has 18 years' worth of observations of the star, cal…
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Interstellar forecast for a nearby star: Raining comets! The comets are plunging into the star HD 172555, which resides 95 light-years from Earth. The comets were not seen directly around the star. Astronomers inferred their presence when they used NASA's Hubble Space Telescope to detect gas that is likely the vaporized remnants of their icy nuclei. The presence of these doomed comets provides circumstantial evidence for "gravitational stirring" by an unseen Jupiter-size planet, where comets deflected by the massive object's gravity are catapulted into the star. These events also provide new insights into the past and present activity of comets in our solar system. It's…
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In 1977, NASA's Voyager 1 and 2 spacecraft began their pioneering journey across the solar system to visit the giant outer planets. Now, the Voyagers are hurtling through unexplored territory on their road trip beyond our solar system. Along the way, they are measuring the interstellar medium, the mysterious environment between stars that is filled with the debris from long-dead stars. NASA's Hubble Space Telescope is providing the road map, by measuring the material along the probes' trajectories as they move through space. Hubble finds a rich, complex interstellar ecology, containing multiple clouds of hydrogen, laced with other elements. Hubble data, combined with the …
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Two glowing nebulas in the Small Magellanic Cloud, a dwarf galaxy that is a satellite of our Milky Way galaxy, have been observed by NASA's Hubble Space Telescope. Young, brilliant stars at the center of each nebula are heating hydrogen, causing these clouds of gas and dust to glow red. The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). Astronomers are using Hubble to probe the Milky Way satellite to understand how dust is different in galaxies that have a far lower supply of heavy elements needed to create dust. View the full article
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Space Telescope Science Institute to Host Data from World's Largest Digital Sky Survey
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Data from the world's largest digital sky survey is being publicly released today by the Space Telescope Science Institute (STScI) in Baltimore, Maryland, in conjunction with the University of Hawaii Institute for Astronomy in Honolulu, Hawaii. Data from the Pan-STARRS1 Surveys will allow anyone to access millions of images and use the database and catalogs containing precision measurements of billions of stars and galaxies. The four years of data comprise 3 billion separate sources, including stars, galaxies, and various other objects. The immense collection, only a fraction of which is being released today, contains nearly 2 petabytes of data, which is equivalent to two…
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