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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One doesn't need a Ph.D. in astrophysics to recognize there is something odd-looking about this otherwise beautiful galaxy, NCG 4485. Like the Batman character Two-Face, one side looks normal, but the other side looks contorted with a firestorm of star formation going on. Why the colorful asymmetry in an island star city many thousands of light-years across? The clue is off the edge of the photo. It's another galaxy, NGC 4490, that swept by NGC 4485 millions of years ago. The gravitational taffy pull between the two galaxies compressed interstellar gas to trigger a flurry of new star birth as seen in the abundance of young blue stars and pinkish nebulas. So, out of a near…
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How far is far? And, how do you know when you get there? In 1995, astronomers decided to use the Hubble Space Telescope to conduct a bold and daring experiment to address this puzzle. For 10 consecutive days, Hubble stared at one tiny, seemingly empty patch of sky for 1 million seconds. The gamble of precious telescope time paid off. Hubble captured the feeble glow of myriad never-before-seen galaxies. Many of the galaxies are so far away it has taken billions of years for their light to reach us. Therefore, the view is like looking down a "time corridor," where galaxies can be seen as they looked billions of years ago. Hubble became astronomy's ultimate time machine. …
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There is something wrong with our universe. Or, more specifically, it is outpacing all expectations for its present rate of expansion. Something is amiss in astronomers' efforts to measure the past and predict the present, according to a discrepancy between the two main techniques for measuring the universe's expansion rate – a key to understanding its history and physical parameters. The inconsistency is between the Hubble Space Telescope measurements of today's expansion rate of the universe (by looking at stellar milepost markers) and the expansion rate as measured by the European Space Agency's Planck satellite. Planck observes the conditions of the early universe…
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This Hubble image shows the results of two stellar companions in a gravitational waltz, several thousand light-years from Earth in the southern constellation Centaurus. The stellar duo, consisting of a red giant and white dwarf, are too close together to see individually in this view. But the consequences of their whirling about each other are two vast shells of gas expanding into space like a runaway hot air balloon. Both stars are embedded in a flat disk of hot material that constricts the outflowing gas so that it only escapes away above and below the stars. This apparently happens in episodes because the nebula has two distinct nested hourglass-shaped structures. The …
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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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Astronomers once thought asteroids were boring, wayward space rocks that simply orbit around the Sun. These objects were dramatically presented only in science fiction movies. But recent observations show that asteroids are anything but dull. In reality they are dynamic, active worlds that can ultimately disintegrate due to the long-term subtle effects of sunlight, which can slowly spin them up until they begin to shed material. Several telescopes, including NASA's Hubble Space Telescope, have caught the gradual self-destruction of the asteroid (6478) Gault. Images from Hubble show two narrow, comet-like tails of dusty debris streaming from the diminutive asteroid. …
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We live in a gigantic star city. Our Milky Way galaxy contains an estimated 200 billion stars. But that's just the bare tip of the iceberg. The Milky Way is surrounded by vast amounts of an unknown material called dark matter that is invisible because it doesn't release any radiation. Astronomers know it exists because, dynamically, the galaxy would fly apart if dark matter didn't keep a gravitational lid on things. Still, astronomers would like to have a precise measure of the galaxy's mass to better understand how the myriad galaxies throughout the universe form and evolve. Other galaxies can range in mass from around a billion solar masses to 30 trillion solar masses…
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NASA has recovered the Hubble Space Telescope's Advanced Camera for Surveys instrument, which suspended operations on Thursday, Feb. 28, 2019. The final tests were conducted and the instrument was brought back to its operational mode on March 6. View the full article
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At 8:31 p.m. EST on February 28, 2019, the Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope suspended operations after an error was detected as the instrument was performing a routine boot procedure. The error indicated that software inside the camera had not loaded correctly. A team of instrument system engineers, flight software experts, and flight operations personnel quickly organized to download and analyze instrument diagnostic information. This team is currently working to identify the root cause and then to construct a recovery plan. View the full article
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The phrase "a chip off the old block" apparently also applies to the outer moons of our solar system. A tiny moon whirling around Neptune that was uncovered in Hubble Space Telescope photographs taken in 2013 has puzzled astronomers ever since then because it is very close to a much larger moon named Proteus. The orbits of the two moons are presently 7,500 miles apart. Proteus, at 260 miles in diameter, is roughly the size of the state of Ohio. By contrast, Hippocamp is just 20 miles across, or the size of metropolitan Columbus, Ohio. Proteus should have gravitationally swept aside or swallowed the moon while clearing out its orbital path. Smoking-gun evidence for H…
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The two major planets beyond Saturn have only been visited once by a spacecraft, albeit briefly. NASA's Voyager 2 spacecraft swung by Uranus in 1986, and Neptune in 1989. Our robotic deep-space tourist snapped the only close-up, detailed images of these monstrous worlds. For Neptune, the images revealed a planet with a dynamic atmosphere with two mysterious dark vortices. Uranus, however, appeared featureless. But these views were only brief snapshots. They couldn't capture how the planets' atmospheres change over time, any more than a single snapshot of Earth could tell meteorologists about weather behavior. And, they go through protracted seasonal changes in their multi…
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The universe is very cluttered. Myriad island cities of stars, the galaxies, form a backdrop tapestry. Much closer to home are nebulae, star clusters, and assorted other foreground celestial objects that are mostly within our Milky Way galaxy. Despite the vastness of space, objects tend to get in front of each other. This happened when astronomers used the Hubble Space Telescope to photograph the globular star cluster NGC 6752 (located 13,000 light-years away in our Milky Way's halo). In a celestial game of "Where's Waldo?," Hubble's sharp vision uncovered a never-before-seen dwarf galaxy located far behind the cluster's crowded stellar population. The loner galaxy is i…
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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 Hawai’i 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. This data release contains over 1.6 petabytes of data (a petabyte is one million gigabytes), making it the largest volume of astronomical information ever released. The survey data resides in the Mikulski Archive for Space Telescopes (MAST), which se…
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Two's company and three's a crowd. But thousands are a mosh pit. That's the case in the giant Coma cluster of more than 1,000 galaxies. Hubble spotted a wayward spiral galaxy losing its gas as it plunges toward the center of the massive cluster and is roughed up as it plows through the intergalactic medium. Telltale evidence lies in a long, thin streamer of material that is stretching like taffy from the galaxy's core and on into intergalactic space. Gas is the lifeblood of a galaxy, fueling the birth of new stars. Once it is stripped of all of its gas, the galaxy, named D100, will enter retirement and shine only by the feeble glow of its aging, red stars. D100 is bei…
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The Hubble Space Telescope's Wide Field Camera 3 was brought back to full operational status and completed its first science observations just after noon EST today, Jan. 17, 2019. View the full article
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NASA has moved closer to conducting science operations again with the Hubble Space Telescope's Wide Field Camera 3 instrument, which suspended operations on Tuesday, Jan. 8, 2019. Today, Jan. 15, the instrument was brought back to its operations mode. After resetting the telemetry circuits and associated boards, additional engineering data were collected and the instrument was brought back to operations. All values were normal. Additional calibration and tests will be run over the next 48 to 72 hours to ensure that the instrument is operating properly. Assuming that all tests work as planned, it is expected that the Wide Field Camera 3 will start to collect science images…
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NASA continues to work toward recovering the Hubble Space Telescope’s Wide Field Camera 3 instrument, which suspended operations on Tuesday, January 8. A team of instrument system engineers, Wide Field Camera 3 instrument developers, and other experts formed and quickly began collecting all available telemetry and onboard memory information to determine the sequence of events that caused the values to go out of limits. This team is currently working to identify the root cause and then to construct a recovery plan. If a significant hardware failure is identified, redundant electronics built into the instrument will be used to recover and return it to operations. V…
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Less than a billion years after the big bang, a monster black hole began devouring anything within its gravitational grasp. This triggered a firestorm of star formation around the black hole. A galaxy was being born. A blowtorch of energy, equivalent to the light from 600 trillion Suns, blazed across the universe. Now, 12.8 billion years later, the Hubble Space Telescope captured the beacon from this event. But Hubble astronomers needed help to spot it. The gravitational warping of space by a comparatively nearby intervening galaxy greatly amplified and distorted the quasar's light, making it the brightest such object seen in the early universe. It offers a rare opportuni…
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The Wide Field Camera 3 on the Hubble Space Telescope suspended operations on January 8 due to a hardware problem. Hubble will continue to perform science observations with its other three active instruments, while the Wide Field Camera 3 anomaly is investigated. Wide Field Camera 3, installed during Servicing Mission 4 in 2009, is equipped with redundant electronics should they be needed to recover the instrument. View the full article
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Our Sun is not one of the most abundant types of star in our Milky Way galaxy. That award goes to red dwarfs, stars that are smaller and cooler than our Sun. In fact, red dwarfs presumably contain the bulk of our galaxy's planet population, which could number tens of billions of worlds. Surveys by NASA's Kepler Space Telescope and other observatories have shown that rocky planets are common around these diminutive stars. Some of these rocky worlds are orbiting within the habitable zones of several nearby red dwarfs. The temperate climates on such worlds could allow for oceans to exist on their surface, possibly nurturing life. That's the good news. The bad news is that …
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NASA's Hubble Space Telescope has produced this stunningly detailed portrait of the Triangulum galaxy (M33), displaying a full spiral face aglow with the light of nearly 25 million individually resolved stars. It is the largest high-resolution mosaic image of Triangulum ever assembled, composed of 54 Hubble fields of view spanning an area more than 19,000 light-years across. The Local Group of galaxies is dominated by the Milky Way, Andromeda, and Triangulum. As the junior member of this trio of spiral galaxies, Triangulum provides the valuable comparisons and contrasts that only a close companion can. Most notably, Triangulum's star formation is 10 times more intense t…
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On December 13th, NASA’s Hubble Space Telescope photographed comet 46P/Wirtanen, a periodic comet that orbits the Sun once every 5.4 years. These observations were taken days before the comet’s closest approach to Earth on December 16th, when it passed just over 7 million miles from our planet. Astronomers took advantage of this unusually close approach to study the comet’s inner cloud of gas and dust, or coma, in detail. Their goal was to study how gases are released from ices in the nucleus, what the comet’s ices are composed of, and how gas in the coma is chemically altered by sunlight and solar radiation. In this image, the comet’s nucleus is hidden in the center of a…
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Utilizing the powerful Hubble Frontier Fields observations of galaxy clusters, a study demonstrates that intracluster light — the light of stars orphaned in galaxy cluster mergers — aligns with dark matter, tracing its distribution more accurately than other methods. With broader use, astronomers think the technique could be a first step in exploring the nature of the unobservable, elusive dark matter that makes up the majority of the universe. View the full article
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In nabbing exoplanets that are precariously close to their stars, astronomers have discovered a shortage of one type of alien world. It's a predicted class of Neptune-sized world that orbits just a few million miles from its star, much closer than the 93-million-mile distance between Earth and the Sun. Dubbed "hot Neptunes," these planets would have atmospheres that are heated to more than 1,700 degrees Fahrenheit (hot enough to melt silver). However, the mysterious hot-Neptune deficiency suggests that these planets are rare, or, they were plentiful at one time, but have since disappeared. In fact, most of the known Neptune-sized exoplanets are merely "warm," because th…
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The worldwide astronomical community mourns the loss of Riccardo Giacconi, the first permanent director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. View the full article
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