Astro Blog

By Adithi Ramakrishnan, Associated Press Excerpt: Scientists have unlocked one of the solar system’s many secrets from an unexpected source: a planetarium show opening to the public on Monday. At the American Museum of Natural History last fall, experts were hard at work preparing “Encounters in the Milky Way,” .... They were fine-tuning a scene featuring what’s known as the Oort Cloud, a region far beyond Pluto filled with icy relics from the solar system’s formation. ...scientists have never glimpsed its true shape. One evening while watching the Oort Cloud scene, scientists noticed something strange projected onto the planetarium’s dome. “Why is there a spiral there?” ...The inner section of the Oort Cloud, made of billions of comets, resembled a bar with two waving arms, similar to the shape of our Milky Way galaxy. ...Scientists had long thought the Oort Cloud was shaped like a sphere or flattened shell, warped by the push and pull of other planets and the Milky Way itself. Th...

https://www.sciencemag.org/news/2020/01/how-many-our-comets-come-alien-solar-systems Source:   By Eva Frederick, Science Magazine. Excerpt: Comets are generally thought to originate in our Solar System, made up of the leftover gas and rocks thrown out as the planets formed. The recent arrival of two interstellar objects—a rock named ‘Oumuamua and a flashy comet called Borisov—have challenged that assumption. Tom Hands, an astrophysicist at the University of Zurich’s Institute for Computational Science and his co-author Walter Dehnen at Ludwig Maximilian University of Munich used mathematical models to estimate just how many long-period comets—those that take 200 years or longer to circle the Sun—could be interstellar visitors. ...We estimated from the study that there should be 100,000 ‘Oumuamua-style small rocks and 100 Borisov-style comets in the Solar System. Making far more conservative estimates for how long these objects would survive in the Solar System [shorter than 10 ...

https://www.scientificamerican.com/article/astronomers-spot-first-ever-space-rock-from-another-star/ Source:   By Lee Billings, Scientific American Excerpt: For the first time ever, an asteroid or comet from another star has been caught hurtling through our solar system, astronomers announced late Thursday. Provisionally designated A/2017 U1, the object appears to be less than a half-kilometer in diameter and is traveling at just over 40 kilometers per second—faster than humanity’s speediest outbound space probes. Because this is the first object of its type to be found, there are as yet no official rules for naming it, and its discoverers have balked at suggesting anything besides “Interstellar.” Whatever one might call it, though, it is presently racing away from the sun and has sparked a stampede of astronomers rushing to observe it before it fades entirely from view in the darkness of interstellar space. “All we can say right now is this was something that was tossed out of...

https://www.nwhm.org/education-resources/biography/biographies/maria-mitchell-bio/ Source:   By Writer's Almanac For Investigation:   Excerpt: Today is the birthday of Maria Mitchell ..., the first acknowledged female astronomer, born in 1818 on the island of Nantucket in Massachusetts. ...Maria Mitchell's Quaker parents believed that girls should have the same access to education and the same chance to aspire to high goals as boys, and they raised all 10 of their children as equals. Maria's early interest in science and the stars came from her father, a dedicated amateur astronomer who shared with all his children what he saw as physical evidence of God in the natural world, although Maria was the only child interested enough to learn the mathematics of astronomy.  ...By age 12, Maria was assisting her father with his astronomical observations and data, and just five years later opened and ran her own school for girls, training them in the sciences and math. In 183...

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/...

Source:   By Eric Hand, Science Excerpt:  In August 2014, the European Space Agency’s Rosetta spacecraft arrived at comet 67P/Churyumov-Gerasimenko. Once in orbit, it swooped as low as 10 kilometers to get unprecedented data from the comet (and to drop off its short-lived Philae lander). Today, Science is publishing a suite of new papers detailing some of the mission’s first findings, .... Active pits... Erosion from cliff faces... boulders on unstable slopes... jetting...fissure...comet vomit...windlike features....  http://news.sciencemag.org/space/2015/01/ten-new-rosetta-images-reveal-comet-67p-all-its-glory *. http://news.sciencemag.org/space/2015/01/ten-new-rosetta-images-reveal-comet-67p-all-its-glory

Source:   By Kenneth Chang, The New York Times Excerpt: One of the first scientific findings to emerge from close-up study of a comet has all but settled a question that planetary scientists have debated for decades. The new finding, from the European Space Agency’s mission to the little duck-shaped comet called 67P/Churyumov-Gerasimenko, appears to eliminate the possibility that the water in Earth’s oceans came from melted comets. Water vapor streaming off the comet contains a higher fraction of “heavy hydrogen” than the water on Earth does, scientists reported on Wednesday. “That now probably rules out” comets as the primary source of terrestrial water, said Kathrin Altwegg, a scientist at the University of Bern in Switzerland and the principal investigator for the Rosetta instrument that made the measurements. With comets unlikely, most astronomers now think Earth’s water came from asteroids. ...The new findings, published in the journal Science, came after Rosetta arrived at...

Source:   Kenneth Chang, The New York Times Excerpt: In a technological feat that gives scientists their first opportunity to dig into a remnant of the early solar system, the European Space Agency’s Rosetta mission successfully placed a small spacecraft on the surface of ... Comet 67P/Churyumov-Gerasimenko, a 2.5-mile-wide ball of rock, ice and dust moving faster than 40,000 miles an hour,....” The agency’s director general, Jean-Jacques Dordain said at a news conference... “Not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a probe to a comet’s surface.” ...For scientists, one of the central mysteries that Rosetta will explore is whether Earth’s oceans are filled with melted comets ... slamming into the Earth early on.... See also interview with Joel W. Parker , planetary scientist.... http://www.nytimes.com/2014/11/13/science/space/european-space-agencys-spacecraft-lands-on-comets-surface.html

Source:    M. R. Showalter, Science  Excerpt: Jupiter’s main ring shows vertical corrugations reminiscent of those recently detected in the rings of Saturn. The Galileo spacecraft imaged a pair of superimposed ripple patterns in 1996 and again in 2000. These patterns behave as two independent spirals.... We associate this with the Shoemaker-Levy 9 impacts of July 1994. ...Impacts by comets or their dust streams are regular occurrences in planetary rings, altering them in ways that remain detectable decades later. www.sciencemag.org/cgi/content/abstract/332/6030/711