Astro Blog

Source:   Writer's Almanac Excerpt: ...Before he made his discovery, everyone thought that our Milky Way galaxy was the only galaxy in the universe, and that there wasn’t much outside it besides the Magellanic Clouds, which are visible by the naked eye in the Southern Hemisphere, and which were thought to be clouds of gas or dust. ...Hubble first published his discovery in a paper called “Extragalactic Nature of Spiral Nebulae,” which was presented on this date, in his absence, at a joint meeting of the American Astronomical Society and the American Association for the Advancement of Science. ...Hubble had written his doctoral dissertation on “Photographic Investigations of Faint Nebulae.” With older or smaller telescopes, nebulae just looked like clouds of glowing gas, but with the Hooker telescope — the most powerful telescope in the world at that time — Hubble was able to see that there were actually stars within the nebula. One of the stars in the Andromeda Nebula turned ou...

Source:   By National Radio Astronomy Observatory Excerpt: Astronomers now know that our galaxy is teeming with planets, from rocky worlds roughly the size of Earth to gas giants bigger than Jupiter. Nearly every one of these exoplanets has been discovered in orbit around a mature star with a fully evolved planetary system. New observations with the Atacama Large Millimeter/submillimeter Array (ALMA) contain compelling evidence that two newborn planets, each about the size of Saturn, are in orbit around a young star known as HD 163296. These planets, which are not yet fully formed, revealed themselves by the dual imprint they left in both the dust and the gas portions of the star’s protoplanetary disk. [see image https://public.nrao.edu/wp-content/uploads/2016/12/imagespr2016cbnrao16cb25nrao16cb25a_nrao-1170x600.jpg ]... https://public.nrao.edu/news/2016-alma-planets-disk/

Source:   By Kenneth Chang, The New York Times Excerpt: An ice sheet with more water than Lake Superior may slake the thirst of future astronauts living on Mars. Using radar soundings from NASA’s Mars Reconnaissance Orbiter spacecraft, scientists probed what lies in Utopia Planitia, a 2,000-mile-wide basin within an ancient impact crater. For decades, the region looked intriguing because of polygonal cracking and scalloped depressions in the landscape. In places on Earth like the Canadian Arctic, patterns like these arise from ice beneath the surface. The ground cracks as ice underneath expands and contracts with the changing temperatures; the scallops, as if carved by an ice cream scoop, are places where the surface sinks as the ice melts. “We’d say, ‘It looks like there’s ground ice there,’” Cassie Stuurman, a graduate student at the University of Texas at Austin, said about Utopia Planitia. “What we haven’t known is how much is there.”n ...Ms. Stuurman, the lead author of an...

Source:   By Eric Hand, Science Excerpt: Today, scientists published their first results from a drilling expedition into Chicxulub crater, the buried remnants of an asteroid impact off the Yucatán Peninsula in Mexico that killed off the dinosaurs 66 million years ago. Their discovery of shocked, granite rocks from deep in the crust placed “out of order” on top of sedimentary rocks validates the dynamic collapse theory of formation for Chicxulub’s peak ring, the scientists says. Chicxulub is the only well-preserved crater on Earth with a peak ring, but they abound elsewhere in the inner solar system. Last month, scientists using instruments on a NASA lunar mission showed that the peak rings within the Orientale impact basin were likely to have formed in a similar way as at Chicxulub.... http://www.sciencemag.org/news/2016/11/update-drilling-dinosaur-killing-impact-crater-explains-buried-circular-hills

Source:   By Paul Voosen, Science Excerpt: Some 3.8 billion years ago... A 930-kilometer-wide impact basin perched on the moon’s visible edge, [Mare] Orientale resembles a bull’s-eye, with a smooth interior encircled by three rough rings. ...Do any of the rings match the original crater rim left by the striking asteroid or comet? Now, a new subsurface moon map from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, published today in Science, suggests that the answer is no. ...GRAIL’s two spacecraft...measured Orientale from a scant altitude of 2 kilometers. At such close range, the spacecraft were exceptionally sensitive to tiny changes in the moon’s gravity caused by buried rocks of different density–giving the GRAIL team a picture of the subsurface, and a better idea of how the impact actually went down. They found that the Orientale strike hollowed out a crater some 320 to 460 kilometers wide—smaller than any of the rings. Within an hour, the crater’s steep wa...

Source:    By   Robert Sanders , UC Berkeley Media relations Excerpt: Tabby’s star has provoked so much excitement over the past year, with speculation that it hosts a highly advanced civilization capable of building orbiting megastructures to capture the star’s energy, that UC Berkeley’s Breakthrough Listen project is devoting hours of time on the Green Bank radio telescope to see if it can detect any signals from intelligent extraterrestrials. ...“The Breakthrough Listen program has the most powerful SETI [Search for Extraterrestrial Intelligence] equipment on the planet, and access to the largest telescopes on the planet,” said Andrew Siemion, director of the Berkeley SETI Research Center and co-director of Breakthrough Listen. “We can look at it with greater sensitivity and for a wider range of signal types than any other experiment in the world. ” ...“Everyone, every SETI program telescope, I mean every astronomer that has any kind of telesco...

Source:   Lee Billings, Scientific American Excerpt: Follow the pioneering spacecraft’s final descent to the bizarre surface of the distant space traveler.... Shortly before 5 A.M. Eastern time on Friday, the European Space Agency’s Rosetta spacecraft [did] gently fire its thrusters for a few minutes and begin a 14-hour descent to Comet 67P, a mountain-size, snowy dust ball drifting through the darkness that reigns more than half a billion kilometers from the sun. Starved of solar power, Rosetta’s mission is coming to an end after more than a decade of operations, concluding with a crash into the comet it has shadowed through deep space for two years.  [Includes links to other articles about Rosetta's successes.] See also Silence, hugs, and applause as Rosetta’s 12-year mission ends with landing on comet , by Daniel Clery, and  New York Times article  Rosetta Mission Ends With Spacecraft’s Dive Into Comet http://www.scientificamerican.com/article/...