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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What do astronomers do when a planet they are studying suddenly seems to disappear from sight? In the legendary Star Wars galaxy (you know, "a long time ago and far, far away") the planet might have been the victim of the evil empire's planet-zapping Death Star. But this is pretty improbable in our own cosmic back yard. The missing-in-action planet was last seen orbiting the star Fomalhaut, just 25 light-years away. (In fact, Fomalhaut is so close to us that it's one of the brightest stars in the sky, in the constellation of Pisces Austrinus, the Southern Fish.) A team of researchers from the University of Arizona believe a full-grown planet never existed in the first p…
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Astronomers have uncovered more than 4,000 planets that orbit stars outside our solar system. But they have few details on the planets' chemical makeup and how they were assembled inside a swirling disk of rock and ice encircling their stars. The stars are too far away for us ever to visit them and see the planet-making recipe close-up. Now, a sample from a distant star system has landed in our solar system's back yard. Comet Borisov, the first vagabond comet ever to enter our solar system, offers chemical clues to the composition of an object born around another star. Comets are made of gas, ice, and dust that are part of a planet's building blocks. Borisov's unusu…
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Like detectives carefully building a case, astronomers gathered evidence and eliminated suspects until they found the best evidence yet that the death of a star, first witnessed in X-rays, could be traced back to an elusive mid-sized black hole. The result is a long-sought win for astronomy, as the mid-sized "missing link" in the black hole family has thus far thwarted detection. NASA's Hubble Space Telescope was used to follow up on multiple X-ray observations of a suspected tidal disruption event. This is caused when a wayward star comes too close to the gravity well of a black hole and gets shredded by its tidal forces. The intense heat from stellar cannibalism betrays…
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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 at a university or research center of their choosing in the United States. View the full article
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The weather forecast for galaxies hosting monster, active black holes is blustery. Engorged by infalling material, a supermassive black hole heats so much gas that it can shine 1,000 times brighter than its host galaxy. But that’s not all. Hubble astronomers found that the region around the black hole emits so much radiation that it pushes out material at a few percent the speed of light (a speed fast enough to travel from Earth to the Moon in a few minutes). This material slams into a host galaxy’s lanes of gas and dust, preventing the formation of new stars. The torrential winds are snowplowing the equivalent of hundreds of solar masses of material each year. And, the…
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A simple single-cell organism that may be growing on your lawn is helping astronomers probe the largest structures in the universe. These organisms, called slime mold, feed on dead plant material, and they have an uncanny ability to seek out food sources. Although brainless, the organism's "genius" at creating efficient networks to reach its food goal has caught the attention of scientists. Researchers have recreated the slime mold's behavior in computer algorithms to help solve large-scale engineering problems such as finding the most efficient traffic routes in large cities, solving mazes, and pinpointing crowd evacuation routes. A team of astronomers has now turned…
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Through its 30 years of discoveries and awesome celestial images, the legendary Hubble Space Telescope has redefined the universe for new generations of astronomers and the public alike. This would not have been possible without the perseverance and expertise of a team of Hubble operations experts at the Space Telescope Science Institute, NASA's Goddard Space Flight Center, and the Lockheed Martin Corporation. In recognition of Hubble's scientific prowess and longevity, the National Air and Space Museum in Washington, D.C. has awarded their 2020 Collins Trophy for Current Achievement to the Hubble operations team. "Through the efforts of the Hubble team the observator…
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Like a desperado in the Wild West, the broad "brim" of the Sombrero galaxy's disk may conceal a turbulent past. The Sombrero (M104) has never been a galaxy to fit the mold. It has an intriguing mix of shapes found in disk-shaped spiral galaxies, as well as football-shaped elliptical galaxies. The story of its structure becomes stranger with new evidence from the Hubble Space Telescope indicating the Sombrero is the result of major galaxy mergers, though its smooth disk shows no signs of recent disruption. The galaxy's faint halo offers forensic clues. It's littered with innumerable stars that are rich in heavier elements (called metals), because they are later-generatio…
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Astronomers searching archival data from NASA's Kepler exoplanet hunting mission identified a previously unknown dwarf nova that underwent a super-outburst, brightening by a factor of 1,600 times in less than a day. While the outburst itself has a theoretical explanation, the slow rise in brightness that preceded it remains a mystery. Kepler's rapid cadence of observations were crucial for recording the entire event in detail. The dwarf nova system consists of a white dwarf star with a brown dwarf companion. The white dwarf is stripping material from the brown dwarf, sucking its essence away like a vampire. The stripped material forms an accretion disk around the white …
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To date astronomers have discovered over 4,000 planets orbiting other stars. Statistically, there should be over 100 billion planets in our Milky Way galaxy. They come in a wide range of sizes and characteristics, largely unimagined before exoplanets were first discovered in the mid-1990s. The biggest motivation for perusing these worlds is to find "Genesis II," a planet where life has arisen and evolved beyond microbes. The ultimate payoff would be finding intelligent life off the Earth. A major step in searching for habitable planets is finding suitable stars that could foster the emergence of complex organisms. Because our Sun has nurtured life on Earth for nearly 4 …
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People use the phrase "Holy Cow" to express excitement. Playing with that phrase, researchers from an international collaboration developed an acronym—H0LiCOW—for their project's name that expresses the excitement over their Hubble Space Telescope measurements of the universe's expansion rate. Knowing the precise value for how fast the universe expands is important for determining the age, size, and fate of the cosmos. Unraveling this mystery has been one of the greatest challenges in astrophysics in recent years. Members of the H0LiCOW (H0 Lenses in COSMOGRAIL's Wellspring) team used Hubble and a technique that is completely independent of any previous method to meas…
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When searching for dark matter, astronomers must go on a sort of "ghost hunt." That's because dark matter is an invisible substance that cannot be seen directly. Yet it makes up the bulk of the universe's mass and forms the scaffolding upon which galaxies are built. Dark matter is the gravitational "glue" that holds galaxies as well as galaxy clusters together. Astronomers can detect its presence indirectly by measuring how its gravity affects stars and galaxies. The mysterious substance is not composed of the same stuff that makes up stars, planets, and people. That material is normal "baryonic" matter, consisting of electrons, protons, and neutrons. However, dark mat…
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Galaxies are like snowflakes. Though the universe contains innumerable galaxies flung across time and space, no two ever look alike. One of the most photogenic is the huge spiral galaxy UGC 2885, located 232 million light-years away in the northern constellation, Perseus. It's a whopper even by galactic standards. The galaxy is 2.5 times wider than our Milky Way and contains 10 times as many stars, about 1 trillion. This galaxy has lived a quiescent life by not colliding with other large galaxies. It has gradually bulked up on intergalactic hydrogen to make new stars at a slow and steady pace over many billions of years. The galaxy has been nicknamed "Rubin's galaxy," aft…
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In the year 1054 AD, Chinese sky watchers witnessed the sudden appearance of a "new star" in the heavens, which they recorded as six times brighter than Venus, making it the brightest observed stellar event in recorded history. This "guest star," as they described it, was so bright that people saw it in the sky during the day for almost a month. Native Americans also recorded its mysterious appearance in petroglyphs. Observing the nebula with the largest telescope of the time, Lord Rosse in 1844 named the object the "Crab" because of its tentacle-like structure. But it wasn't until the 1900s that astronomers realized the nebula was the surviving relic of the 1054 supern…
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NASA's upcoming Wide Field Infrared Survey Telescope (WFIRST), scheduled for launch in the mid-2020s, will have the power to survey the sky 1,000 times faster than the Hubble Space Telescope, with Hubble-quality detail, in the near-infrared. A simulated image of a 34,000-light-year swath across our neighboring galaxy Andromeda showcases WFIRST’s unique detector configuration, expansive field of view and high resolution. The image was generated using data collected by Hubble, and shows the red and infrared light of more than 50 million individual stars in Andromeda, as they would appear with WFIRST. WFIRST is designed to address key questions across a wide range of…
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When astronomers look around the solar system, they find that planets can be made out of almost anything. Terrestrial planets like Earth, Mars, and Venus have dense iron cores and rocky mantles. The massive outer planets like Jupiter and Saturn are mostly gaseous and liquid. Astronomers can't peel back their cloud layers to look inside, but their composition is deduced by comparing the planet's mass (as calculated from its orbital motion) to its size. The result is that Jupiter has the density of water, and Saturn has an even lower density (it could float in a huge bathtub). These gas giants are just 1/5th the density of rocky Earth. Now astronomers have uncovered a com…
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The American Association for the Advancement of Science (AAAS) Council has elected Kathryn Flanagan of the Space Telescope Science Institute (STScI) and Colin Norman of STScI and Johns Hopkins University, and 441 other AAAS members as Fellows of the AAAS. Dr. Flanagan is cited by the AAAS for her lead role calibrating grating spectrometers for NASA's Chandra X-ray Observatory mission; X-ray observations of astrophysical plasmas; and leadership in the James Webb Space Telescope project. Dr. Norman is cited by the AAAS for distinguished contributions to an array of subjects in theoretical astrophysics, especially in the areas of the interstellar medium, galaxy dynamics,…
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When astronomers see something in the universe that at first glance seems like one-of-a-kind, it's bound to stir up a lot of excitement and attention. Enter comet 2I/Borisov. This mysterious visitor from the depths of space is the first identified comet to arrive here from another star. We don't know from where or when the comet started heading toward our Sun, but it won't hang around for long. The Sun's gravity is slightly deflecting its trajectory, but can't capture it because of the shape of its orbit and high velocity of about 100,000 miles per hour. Telescopes around the world have been watching the fleeting visitor. Hubble has provided the sharpest views as the co…
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The Star Wars film trilogies are known best for the iconic "Death Star," an alien battle station that shoots out beams of directed energy powerful enough to blow up planets. The real universe makes much more extraordinary beams that can unleash in a few seconds as much energy as our sun will generate over its 10-billion-year lifetime. These beams blast out of imploding stars at over 99% the speed of light. They carry most of their energy in the form of gamma-rays—a lethal form of radiation that can penetrate bone and tear apart living cells. If our planet got caught in a nearby gamma-ray burst (GRB) the atmosphere would be largely stripped away. The current record for a…
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Supermassive black holes, weighing millions or even billions of times our Sun's mass, are still only a tiny fraction of the mass of the galaxies they inhabit. But in some cases, the central black hole is the tail wagging the dog. It seems that black holes can run hot or cold when it comes to either enhancing or squelching star birth inside a cluster of galaxies. Typically, giant black holes, pumping out energy via jets, keep interstellar gas too warm to condense and form stars. Now, astronomers have found a cluster of galaxies, called the Phoenix cluster, where stars are forming at a furious rate because of the black hole's influence. This stellar turboboost is apparent…
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The “funhouse mirror” has delighted carnival-goers for more than a century by twisting peoples’ images into wildly distorted shapes. Its prolific inventor, Charles Frances Ritchel, called it the "Ritchel's Laugh-O-Graphs.” However, there was nothing funny – but instead practical – about warped images as far as Albert Einstein was concerned. In developing his general theory of relativity, Einstein imagined the universe as a grand funhouse mirror caused by wrinkles in the very fabric of space. This recent picture from Hubble shows a galaxy nicknamed the "Sunburst Arc" that has been split into a kaleidoscope illusion of no fewer than 12 images formed by a massive foregro…
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The universe is a bubbling cauldron of matter and energy that have mixed together over billions of years to create a witches' brew of birth and destruction. Firestorms of star birth sweeping across the heavens. Dying stars rattling the very fabric of space in titanic explosions. Death Star-like beams of energy blasting out of overfed black holes at nearly the speed of light. Large galaxies devouring smaller companions, like cosmic Pac-Men. Colossal collisions between galaxies flinging stars around like breaking pool balls. Hubble has seen them all. This compulsive mayhem in space can produce weird-looking shapes that resemble creepy creatures seemingly conjured up in…
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You’ve probably never noticed it, but our solar system is moving along at quite a clip. Stars in the outer reaches of the Milky Way, including our Sun, orbit at an average speed of 130 miles per second. But that’s nothing compared to the most massive spiral galaxies. “Super spirals,” which are larger, brighter, and more massive than the Milky Way, spin even faster than expected for their mass, at speeds up to 350 miles per second. Their rapid spin is a result of sitting within an extraordinarily massive cloud, or halo, of dark matter – invisible matter detectable only through its gravity. The largest “super spiral” studied here resides in a dark matter halo weighing at …
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No one knows where it came from. No one knows how long it has been drifting through the empty, cold abyss of interstellar space. But this year an object called comet 2I/Borisov came in from the cold. It was detected falling past our Sun by a Crimean amateur astronomer. This emissary from the black unknown captured the attention of worldwide astronomers who aimed all kinds of telescopes at it to watch the comet sprout a dust tail. The far visitor is only the second known object to enter our solar system coming from elsewhere in the galaxy, based on its speed and trajectory. Like a racetrack photographer trying to capture a speeding derby horse, Hubble took a series of snap…
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Astronomers have discovered an unexplained surplus of gas flowing into our Milky Way after conducting a galaxy-wide audit of outflowing and inflowing gas. Rather than a gas equilibrium and "balanced books," 10 years of data from NASA's Hubble Space Telescope show there is more gas coming in than going out. It is no secret that the Milky Way is frugal with its gas. The valuable raw material is recycled over billions of years—thrown out into the galactic halo via supernovas and violent stellar winds, and then used to form new generations of stars once it falls back to the galactic plane. The surplus of inflowing gas, however, was a surprise. Hubble distinguished between…
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