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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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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To date, approximately 4,000 planets have been found orbiting other stars. The majority are extremely hostile to any chances for life: with exotic atmospheres, wide temperature extremes, and oddball orbits. Astronomers have now made an important step toward the ultimate goal of finding an exoplanet with an atmosphere more like Earth's, and having moderate temperatures. Water vapor has been identified in the atmosphere of a planet called K2-18b, located 110 light-years away. And, where there's water there could be clouds and rain. The planet is also at the right distance from its star to have a temperate climate where the water doesn't evaporate or freeze. But don't go loo…
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Saturn is so beautiful that astronomers cannot resist using the Hubble Space Telescope to take yearly snapshots of the ringed world when it is near its closest distance to Earth. These images, however, are more than just beauty shots. They reveal a planet with a turbulent, dynamic atmosphere. This year's Hubble offering, for example, shows that a large storm visible in the 2018 Hubble image in the north polar region has vanished. Smaller storms pop into view like popcorn kernels popping in a microwave oven before disappearing just as quickly. Even the planet's banded structure reveals subtle changes in color. But the latest image shows plenty that hasn't changed. The …
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Like batches of cookies, stars are born together in groups. These star clusters, containing as many as 1 million members, evolve over time largely through a gravitational pinball where more massive stars are segregated from lower mass stars. Heavy stars tend to progressively sink toward the central region of the star cluster, while low-mass stars can escape from the system. For the first time, the Hubble Space Telescope has been used to measure the effects of this dynamical aging on star clusters. They are all located 160,000 light-years from Earth in a satellite galaxy, the Large Magellanic Cloud (LMC). The diminutive galaxy is an ideal target because it hosts a select…
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Jupiter is the king of the solar system, more massive than all of the other solar-system planets combined. Although astronomers have been observing the gas-giant planet for hundreds of years, it still remains a mysterious world. Astronomers don't have definitive answers, for example, of why cloud bands and storms change colors, or why storms shrink in size. The most prominent long-lasting feature, the Great Red Spot, has been downsizing since the 1800s. However, the giant storm is still large enough to swallow Earth. The Red Spot is anchored in a roiling atmosphere that is powered by heat welling up from the monster planet's deep interior, which drives a turbulent atm…
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The scorching hot exoplanet WASP-121b represents a new twist on the phrase "heavy metal." There are no loud electric guitar riffs, characteristic of heavy metal music, streaming into space. What is escaping the planet is iron and magnesium gas, dubbed heavy metals, because they are heavier than lightweight hydrogen and helium. The observations by the Hubble Space Telescope represent the first time heavy metal gas has been detected floating away from an exoplanet. A scorching planet, WASP-121b orbits precariously close to a star that is even hotter than our Sun. The intense radiation heats the planet's upper atmosphere to a blazing 4,600 degrees Fahrenheit. Apparently,…
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In 1924, American astronomer Edwin Hubble announced that he discovered galaxies outside of our Milky Way by using the powerful new Hooker telescope perched above Los Angeles. By measuring the distances to these galaxies, he realized the farther away a galaxy is, the faster it appears to be receding from us. This was incontrovertible evidence the universe is uniformly expanding in all directions. For nearly a decade Albert Einstein refused to accept the observational evidence. His theory of general relativity described a static universe. But this could only be accomplished by invoking a "cosmological constant," which he described as repulsive property of space that would c…
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