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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The term "HAZMAT" connotes danger. In this case, it's on a cosmic scale, where violent flares of seething gas from small, young stars may make entire planets uninhabitable. NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT — HAbitable Zones and M dwarf Activity across Time. This is an ultraviolet survey of red dwarfs — referred to as "M dwarfs" in astronomical circles — at three different ages: young, intermediate, and old. Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets orbit these small stars. But young red dwarfs are active stars, producing ultraviolet flar…
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On Friday, October 5, 2018, at approximately 6:00 p.m. EDT, NASA’s Hubble Space Telescope entered safe mode. NASA is working to resume science operations. Hubble’s instruments still are fully operational and are expected to produce excellent science for years to come. View the full article
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Our solar system has eight major planets, and nearly 200 moons. Though astronomers have to date found nearly 4,000 planets orbiting other stars, no moons have yet been found. That hasn't been for any lack of looking, it’s just that moons are smaller than planets and therefore harder to detect. The Hubble and Kepler space telescopes found evidence for what could be a giant moon accompanying a gas-giant planet that orbits the star Kepler-1625, located 8,000 light-years away in the constellation Cygnus. The moon may be as big as Neptune and it orbits a planet several times more massive than Jupiter. If our solar system is a typical example, moons may outnumber planets in…
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Imagine crushing more than 50,000 aircraft carriers into the size of a baseball. This describes neutron stars. They are among the strangest objects in the universe. Neutron stars are a case of extreme physics produced by the unforgiving force of gravity. The entire core of an exploded star has been squeezed into a solid ball of neutrons with the density of an atom’s nucleus. Neutron stars spin as fast as a blender on puree. Some spit out death-star beams of intense radiation — like interstellar lighthouses. These are called pulsars. These beams are normally seen in X-rays, gamma-rays, and radio waves. But astronomers used Hubble's near-infrared (IR) vision to look at a …
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The universe is a big place. The Hubble Space Telescope's views burrow deep into space and time, but cover an area a fraction the angular size of the full Moon. The challenge is that these "core samples" of the sky may not fully represent the universe at large. This dilemma for cosmologists is called cosmic variance. By expanding the survey area, such uncertainties in the structure of the universe can be reduced. A new Hubble observing campaign, called Beyond Ultra-deep Frontier Fields And Legacy Observations (BUFFALO), will boldly expand the space telescope's view into regions that are adjacent to huge galaxy clusters previously photographed by NASA's Spitzer and Hubbl…
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Astronomy has always been a preeminently visual science, going back thousands of years to the early sky watchers. Hubble’s jaw-dropping views of far-flung planets, nebulas, and galaxies have redefined the universe for whole new generations. Nearly all of Hubble’s dazzling images have been prepared with the skills of Zoltan Levay, in the STScI Office of Public Outreach. Levay is retiring now to pursue his hobby of photography on a more earth-bound plane. He leaves behind a 25-year-long legacy of several thousand colorful space pictures that communicate the mystery and wonder of the universe. Levay blended traditional photographic skills with science data to yield aesthetic…
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Astronomers have just assembled one of the most comprehensive portraits yet of the universe’s evolutionary history, based on a broad spectrum of observations by the Hubble Space Telescope and other space and ground-based telescopes. In particular, Hubble’s ultraviolet vision opens a new window on the evolving universe, tracking the birth of stars over the last 11 billion years back to the cosmos’ busiest star-forming period, about 3 billion years after the big bang. This photo encompasses a sea of approximately 15,000 galaxies — 12,000 of which are star-forming — widely distributed in time and space. View the full article
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It takes more than a massive outburst to destroy the mammoth star Eta Carinae, one of the brightest known stars in the Milky Way galaxy. About 170 years ago, Eta Carinae erupted, unleashing almost as much energy as a standard supernova explosion. Yet that powerful blast wasn’t enough to obliterate the star, and astronomers have been searching for clues to explain the outburst ever since. Although they cannot travel back to the mid-1800s to witness the actual eruption, they can watch a rebroadcast of part of the event — courtesy of some wayward light from the explosion. Rather than heading straight toward Earth, some of the light from the outburst rebounded or “echoed” o…
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As Saturn and Mars ventured close to Earth, Hubble captured their portraits in June and July 2018, respectively. The telescope photographed the planets near opposition, when the Sun, Earth and an outer planet are lined up, with Earth sitting in between the Sun and the outer planet. Around the time of opposition, a planet is at its closest distance to Earth in its orbit. Hubble viewed Saturn on June 6, when the ringed world was approximately 1.36 billion miles from Earth, as it approached a June 27 opposition. Mars was captured on July 18, at just 36.9 million miles from Earth, near its July 27 opposition. Hubble saw the planets during summertime in Saturn’s northern hemis…
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Using the powerful Hubble and Gaia space telescopes, astronomers just took a big step toward finding the answer to the Hubble constant, one of the most important and long-sought numbers in all of cosmology. This number measures the rate at which the universe is expanding since the big bang, 13.8 billion years ago. The constant is named for astronomer Edwin Hubble, who nearly a century ago discovered that the universe was uniformly expanding in all directions. Now, researchers have calculated this number with unprecedented accuracy. Intriguingly, the new results further intensify the discrepancy between measurements for the expansion rate of the nearby universe, and tho…
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Using observations from NASA’s Hubble Space Telescope and ground-based observatories, an international team of scientists have confirmed `Oumuamua (oh-MOO-ah-MOO-ah), the first known interstellar object to travel through our solar system, got an unexpected boost in speed and shift in trajectory as it passed through the inner solar system last year. View the full article
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Much of the light in the universe comes from stars, and yet, star formation is still a vexing question in astronomy. To piece together a more complete picture of star birth, astronomers have used the Hubble Space Telescope to look at star formation among galaxies in our own cosmic back yard. The survey of 50 galaxies in the local universe, called the Legacy ExtraGalactic UV Survey (LEGUS), is the sharpest, most comprehensive ultraviolet-light look at nearby star-forming galaxies. The LEGUS survey combines new Hubble observations with archival Hubble images for star-forming spiral and dwarf galaxies, offering a valuable resource for understanding the complexities of st…
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There may be no shortage of balloon-filled birthday parties or people with silly high-pitched voices on the planet WASP-107b. That's because NASA's Hubble Space Telescope was used to detect helium in the atmosphere for the first time ever on a world outside of our solar system. The discovery demonstrates the ability to use infrared spectra to study exoplanet atmospheres. Though as far back as 2000 helium was predicted to be one of the most readily-detectable gases on giant exoplanets, until now helium had not been found — despite searches for it. Helium was first discovered on the Sun, and is the second-most common element in the universe after hydrogen. It's one of the…
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In the fading afterglow of a supernova explosion, astronomers using NASA’s Hubble Space Telescope have photographed the first image of a surviving companion to a supernova. This is the most compelling evidence that some supernovas originate in double-star systems. The companion to supernova 2001ig’s progenitor star was no innocent bystander to the explosion—it siphoned off almost all of the hydrogen from the doomed star’s stellar envelope. SN 2001ig is categorized as a Type IIb stripped-envelope supernova, which is a relatively rare type of supernova in which most, but not all, of the hydrogen is gone prior to the explosion. Perhaps as many as half of all stripped-envelop…
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For 28 years, NASA’s Hubble Space Telescope has been delivering breathtaking views of the universe. Although the telescope has made more than 1.5 million observations of over 40,000 space objects, it is still uncovering stunning celestial gems. The latest offering is this image of the Lagoon Nebula to celebrate the telescope’s anniversary. Hubble shows this vast stellar nursery in stunning unprecedented detail. At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust. This region epi…
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When you want to know the size of a room, you use a measuring tape to calculate its dimensions. But you can’t use a tape measure to cover the inconceivably vast distances in space. And, until now, astronomers did not have an equally precise method to accurately measure distances to some of the oldest objects in our universe – ancient swarms of stars outside the disk of our galaxy called globular clusters. Estimated distances to our Milky Way galaxy’s globular clusters were achieved by comparing the brightness and colors of stars to theoretical models and observations of local stars. But the accuracy of these estimates varies, with uncertainties hovering between 10 per…
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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. View the full article
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Through a quirk of nature called “gravitational lensing,” a natural lens in space amplified a very distant star’s light. Astronomers using Hubble took advantage of this phenomenon to pinpoint the faraway star and set a new distance record for the farthest individual star ever seen. They also used the distant star to test one theory of dark matter, and to probe the make-up of a galaxy cluster. The team dubbed the star “Icarus,” after the Greek mythological character who flew too near the Sun on wings of feathers and wax that melted. Its official name is MACS J1149+2223 Lensed Star 1. View the full article
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Grand, majestic spiral galaxies like our Milky Way are hard to miss. Astronomers can spot these vast complexes because of their large, glowing centers and their signature winding arms of gas and dust, where thousands of glowing stars reside. But some galaxies aren't so distinctive. They are big, but they have so few stars for their size that they appear very faint and diffuse. In fact, they are so diffuse that they look like giant cotton balls. Observations by NASA's Hubble Space Telescope of one such galaxy have turned up an oddity that sets it apart from most other galaxies, even the diffuse-looking ones. It contains little, if any, dark matter, the underlying scaff…
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The universe is so huge that it's estimated that a star explodes as a supernova once every second. Astronomers capture a small fraction of these detonations because they are comparatively short-lived, like fireflies flickering on a summer evening. After skyrocketing to a sudden peak in brightness, a supernova can take weeks to slowly fade away. For the past decade astronomers have been befuddled by a more curious "flash-in-the-pan" that pops up and then disappears in just a few days, not weeks. It's called a Fast-Evolving Luminous Transient (FELT). Only a few FELTs have been seen in telescopic sky surveys because they are so brief. Then along came NASA's Kepler Space …
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In a cosmic tug-of-war between two dwarf galaxies orbiting the Milky Way, only NASA’s Hubble Space Telescope can see who’s winning. The players are the Large and Small Magellanic Clouds, and as they gravitationally tug at each other, one of them has pulled out a huge amount of gas from its companion. This shredded and fragmented gas, called the Leading Arm, is being devoured by the Milky Way and feeding new star birth in our galaxy. But which dwarf galaxy is doing the pulling, and whose gas is now being feasted upon? Scientists used Hubble’s ultraviolet vision to chemically analyze the gas in the Leading Arm and determine its origin. After years of debate, we now have th…
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The adventuring cinema archeologist Indiana Jones would be delighted to find a long-sought relic in his own backyard. Astronomers have gotten lucky enough to achieve such a quest. They identified a very rare and odd assemblage of stars that has remained essentially unchanged for the past 10 billion years. The diffuse stellar island provides valuable new insights into the origin and evolution of galaxies billions of years ago. As far as galaxy evolution goes, this object is clearly a case of “arrested development.” The galaxy, NGC 1277, started its life with a bang long ago, ferociously churning out stars 1,000 times faster than seen in our own Milky Way today. But it ab…
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Finding lots of dust around stars may not sound like anything astronomers would get excited about. The universe is a dusty place. But dust around a young star can be evidence that planet formation is taking place. This isn’t a new idea. In 1755, German Philosopher Immanuel Kant first proposed that planets formed around our Sun in a debris disk of gas and dust. Astronomers imagined that this process might take place around other stars. They had to wait until the early 1980s for the first observational evidence for a debris disk around any star to be uncovered. An edge-on debris disk was photographed around the southern star Beta Pictoris. Beta Pictoris remained the poste…
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Using Hubble and Spitzer space telescopes, scientists studied the “hot Saturn” called WASP-39b — a hot, bloated, Saturn-mass exoplanet located about 700 light-years from Earth. By dissecting starlight filtering through the planet’s atmosphere into its component colors, the team found clear evidence for a large amount of water vapor. In fact, WASP-39b has three times as much water as Saturn does. Although the researchers predicted they’d see water, they were surprised by how much they found. This suggests that the planet formed farther out from the star, where it was bombarded by a lot of icy material. Because WASP-39b has so much more water than Saturn, it must have forme…
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The good news: Astronomers have made the most precise measurement to date of the rate at which the universe is expanding since the big bang. The possibly unsettling news: This may mean that there is something unknown about the makeup of the universe. The new numbers remain at odds with independent measurements of the early universe's expansion. Is something unpredicted going on in the depths of space? Astronomers have come a long way since the early 1900s when they didn't have a clue that we lived in an expanding universe. Before this could be realized, astronomers needed an accurate celestial measuring stick to calculate distances to far-flung objects. At that time, f…
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