Astro Blog

By Science Insider.  Excerpt: Out past Neptune, connected spheres of rock orbit through the solar system like faceless galactic snowmen. Called contact binaries, these objects represent roughly 10% of all planetary building blocks. But how these cosmic curiosities form has remained unclear. Typically, simulations of two colliding space objects model the masses as fluid blobs that squish into a single sphere on impact. But using high-performance computers, ...new models were  able to predict the snowman-shaped contact binaries for the first time , scientists reported this week. As for the origins of the binaries, scientists think they began as single objects formed when gravity pulled together dust, gas, and pebbles in the disc of the early Milky Way. As the disc rotated, it ripped apart such objects into two separate chunks that orbited each other. Over time, gravity gently tugged these chunks back together until they fused into their characteristic two-lobed shape....  F...

By Matthew R. Francis , Eos/AGU.  Excerpt: Our Sun is about halfway through its life, which means Earth is as well. After a star exhausts its hydrogen nuclear fuel, its diameter expands more than a hundredfold, engulfing any unlucky planets in close orbits. That day is at least 5 billion years off for our solar system, but scientists have spotted a possible preview of our world’s fate. Using data from the  TESS (Transiting Exoplanet Survey Satellite) observatory , astronomers  Edward Bryant  of the University of Warwick and  Vincent Van Eylen  of University College London compared systems with stars in the main sequence of their lifetimes—fusing hydrogen, like the Sun—with post–main sequence stars closer to the end of their lifetimes, both with and without planets. “We saw that these planets are getting rarer [as stars age],” Bryant said. In other words,  planets are disappearing as their host stars grow old . The comparison between planetary systems w...

By McKenzie Prillaman , Science.  Excerpt: About 1,400 light-years from Earth sits a  young sunlike star surrounded by cooling gas and teensy silicate minerals . These mineral solids — some of the building blocks of rocky planets — are among the first to condense from the gas, suggesting that they’re kick-starting the creation of planets in a system much like the one earthlings call home, researchers report in the July 17  Nature . “It really is the first time we’ve seen this stage of planet formation in the process,” says planetary scientist Laura Schaefer of Stanford University, who was not involved in the new study. Observing the timeline of these early hot minerals will help researchers better understand how events unfolded billions of years ago in the solar system....  Full article at https://www.sciencenews.org/article/star-earliest-birth-planet-solar-system . 

By PAUL VOOSEN , Science.  Excerpt: In its youth, the Solar System underwent a momentous upheaval: Gravitational tugs between the giant planets threw them off track, causing Jupiter’s orbit to jump closer to the Sun, while Saturn, Uranus, and Neptune were flung outward. The gravity of the rampaging giants scattered Pluto and other icy bodies to the Kuiper belt, shepherded the asteroid belt into its current location, and sent countless bodies crashing into the inner Solar System. For many years, researchers believed this “giant planet instability” occurred 600 million years after the Solar System’s birth 4.57 billion years ago, based on the ages of impact craters mapped on the Moon. Recently, evidence has mounted that it  occurred much earlier . And now, some researchers are homing in on a more precise date, just 60 million years after the Solar System’s formation, based on an analysis of rare meteorites derived from an ancient asteroid family, published today in Science. ...

https://eos.org/articles/saturns-shiny-rings-may-be-pretty-young By  Kimberly M. S. Cartier , Eos/AGU.  Excerpt: ...Data from NASA’s Cassini mission showed how fast dust has been pelting the Saturnian system, revealing that for the rings to have remained as shiny and dust-free as they are, they can be only as much as 400 million years old, much younger than the planet itself. ...The Sun and its planets formed around 4.5 billion years ago, and many of the planets’ moons, including ours, followed not long after. Astronomers initially thought that  Saturn’s rings  formed during that early dynamical period, when large collisions were common. ...The rings’ orbits and compositions support the idea they are old. ...Measurements of the rainfall rate and the total mass of the rings from NASA’s  Cassini spacecraft , which orbited Saturn for 13 years, suggested that the rings must be far younger than the planet; otherwise, they would have disappeared already. Cassini ...

https://skyandtelescope.org/astronomy-news/four-of-uranuss-moons-might-contain-briny-oceans/ By Emily Lakdawala, Sky & Telescope.  Excerpt: A  new paper re-analyzing Voyager observations  suggests that four of Uranus’ five icy satellites also host oceans: Ariel, Umbriel, Titania, and Oberon. (Only small Miranda, intermediate in size between Saturn’s Mimas and Enceladus, appears not to.) The oceans are desperately thin: less than 30 kilometers (20 miles) thick inside Ariel and Umbriel (both of which are about 1,000 kilometers across, similar in size to Saturn’s Tethys and Dione), and less than 50 kilometers thick within Titania and Oberon (which are larger at about 1,500 kilometers, similar to Saturn’s Rhea and Iapetus). If the oceans exist, they would be left over from much larger liquid layers that formed when the moons first formed. ...They’d be extremely briny, hyper-concentrated with whatever dissolved materials helped to lower the temperature at which water would...

https://www.theguardian.com/science/2022/nov/16/meteorite-that-landed-in-cotswolds-may-solve-mystery-of-earths-water By  Hannah Devlin , The Guardian.  Excerpt: Water covers three-quarters of the Earth’s surface and was crucial for the emergence of life, but its origins have remained a subject of active debate among scientists. Now, a 4.6bn-year-old rock that crashed on to a  driveway in Gloucestershire last year  has provided some of the most compelling evidence to date that water arrived on Earth from asteroids in the outer solar system.... 

https://www.science.org/content/article/stars-may-form-10-times-faster-thought Ling Xin, Science Magazine.  Excerpt: Astronomers have long thought it takes millions of years for the seeds of stars like the Sun to come together. Clouds of mostly hydrogen gas coalesce under gravity into prestellar cores dense enough to collapse and spark nuclear fusion, while magnetic forces hold matter in place and slow down the process. But observations using the world’s largest radio telescope are casting doubt on this long gestational period. Researchers have zoomed in on a prestellar core in a giant gas cloud—a nursery for hundreds of baby stars—and found the tiny embryo may be forming 10 times faster than thought, thanks to weak magnetic fields. “If this is proven to be the case in other gas clouds, it will be revolutionary for the star formation community,” says Paola Caselli from the Max Planck Institute for Extraterrestrial Physics, who was not involved with the research.…

https://www.sciencemag.org/news/2020/12/china-lands-its-moon-rocks-inner-mongolia Source:  By   Paul Voosen , Science Magazine.  Excerpt: China’s Chang’e-5 mission made a triumphant return around 1 p.m. EST today, landing in the middle of the night on the dark frozen plains of Inner Mongolia, Chinese   state media reported . The capsule’s return marks the first time China has collected rocks from the Moon—and the first time any nation has accomplished the feat since 1976. The 3-week-long mission   was the most complicated   in the history of China’s robotic space exploration program, involving a lunar landing, furious scooping and drilling of up to 2 kilograms of grit, and then an ascent and rendezvous with an orbiter, which carried the samples back to Earth. The China National Space Administration, typically secretive with its missions, showed growing confidence in its space program, with live broadcasts of the rocket launch and return of its sample caps...

https://www.sciencemag.org/news/2020/12/japan-s-hayabusa2-capsule-lands-carbon-rich-asteroid-samples Source:    By  Dennis Normile , Science Magazine.  Excerpt: Japan has once again retrieved samples from a distant asteroid, which scientists will scrutinize for clues about the ancient delivery of water and organic molecules to Earth. The return capsule of the Hayabusa2 mission—about the size and shape of a wok—parachuted to a landing in the red desert sand of Woomera, Australia, in the early morning of 6 December, after a nearly 5.3-billion-kilometer trip to the asteroid Ryugu. A helicopter team homed in on a radio beacon and found the capsule intact. Launched in 2014 by the Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (JAXA), Hayabusa2 spent 18 months circling Ryugu, making remote observations of  the diamond-shaped rubble pile . It also released several tiny rovers that hopped on the surface gathering data. After ide...

https://www.nasa.gov/press-release/nasa-s-osiris-rex-spacecraft-successfully-touches-asteroid Source:  NASA RELEASE 20-103.  Excerpt: NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Tuesday, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023. This well-preserved, ancient asteroid, known as Bennu, ... offers scientists  a window into the early solar system  as it was first taking shape billions of years ago and flinging ingredients that could have helped seed life on Earth. If Tuesday’s sample collection event, known as “Touch-And-Go” (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the precious primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January.... See also New York Time...

https://www.sciencemag.org/news/2020/10/nasa-mission-about-capture-carbon-rich-dust-former-water-world Source:  By  Paul Voosen , Science Magazine.  Excerpt: OSIRIS-REx is ready to get the goods. On 20 October,  after several years of patient study  of its enigmatic target, NASA’s $800 million spacecraft will finally stretch out its robotic arm, swoop to the surface of the near-Earth asteroid Bennu, and sweep up some dust and pebbles. The encounter, 334 million kilometers from Earth, will last about 10 seconds. If it is successful, OSIRIS-REx could steal away with up to 1 kilogram of carbon-rich material from the dawn of the Solar System for return to Earth in 2023. Since OSIRIS-REx (short for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) arrived in 2018, Bennu has yielded surprises…. Despite the logistical challenge, the boulders contain a prize:  veins of carbonate minerals thicker than your hands , the team rep...

https://www.nasa.gov/image-feature/ames/planetary-impact-simulation s Source:    By Frank Tavares, NASA.  Excerpt: The histories of planets across our solar system and beyond are filled with collisions and transformations. New research is helping scientists understand how colossal impacts, like the one with Earth thought to have formed the Moon, are impacting the atmospheres of rocky planets.In the animation above, a Mars-like mass grazes an Earth-like mass, replicating the traditional theory for the impact that formed the Moon. Some atmosphere is lost, accompanied by a shockwave....    

https://www.sciencemag.org/news/2020/06/missing-mass-planet-formation-found-young-disks-gas-and-dust Source:   By Adam Mann, Science Magazine.  Excerpt: Planets are forming around young stars far faster than scientists expected, arising in a cosmic eye blink of less than half a million years, according to a new study. ...Planets coalesce from massive disks of gas and dust that surround newborn stars. But detecting these embryonic worlds is difficult because both the star and the disk shine far brighter than any tiny planet. To find out how much material is available for planet formation, researchers have used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to weigh the disks around young stars between 1 million and 3 million years old. Past studies found that some lacked the mass to form even a single Jupiter-size world. The results suggested astronomers were either overlooking some hidden reservoir of material or they were looking too late in the planet-for...

https://www.nytimes.com/2019/03/18/science/ultima-thule-new-horizons.html Source:   By Kenneth Chang, The New York Times. Excerpt: ...New Horizons traveled some 4 billion miles to take a close-up look at this 22-mile-long world in the solar system’s icy Kuiper belt beyond Neptune; it is officially designated as 2014 MU69 and nicknamed Ultima Thule. ...a small shard that has been frozen and almost unchanged since it formed 4.5 billion years ago. Ultima Thule was ... full of surprises. The shape turned out to be unlike anything seen in the solar system. ...two objects that at some stage touched and stuck together, like a snowman. Then the scientists discovered that the two lobes of Ultima Thule were not spherical, but more like lumpy pancakes. The larger lobe is also flatter than the smaller one. ...a change from older ideas of planetary formation: that objects called planetesimals grew slowly and steadily in size. Ultima Thule suggests an alternative scenario in which a bunch of...

http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20190102 Source:  By New Horizons Mission. Excerpt: Scientists from NASA's New Horizons mission released the first detailed images of the most distant object ever explored — the Kuiper Belt object nicknamed Ultima Thule. Its remarkable appearance, unlike anything we've seen before, illuminates the processes that built the planets four and a half billion years ago. "This flyby is a historic achievement," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. "Never before has any spacecraft team tracked down such a small body at such high speed so far away in the abyss of space. New Horizons has set a new bar for state-of-the-art spacecraft navigation." The new images — taken from as close as 17,000 miles (27,000 kilometers) on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. End to end, the...

http://pluto.jhuapl.edu/News-Center/ Source:   NASA New Horizons is the superb spacecraft mounted with instruments that gave us all those rich, rich images and data in its flyby of Pluto in July of 2015.  Soon those exquisite instruments can be focused on yet another world in our Solar System, this time a Kuiper Belt object! Ultima is 100 times smaller than Pluto, but was likely formed 4.5 or 4.6 billion years ago, 4 billion miles from the Sun. It's been at near absolute zero temperature ever since, so it's likely the best sample of the ancient solar nebula ever studied. Will Ultima turn out to be a collection smaller bodies? Will it have an atmosphere? Will it have rings? Will it have moons? Any of that could be possible, and soon we'll know the answers to these questions. It flies by Ultima News Years Day — 2019 Jan 1. Get ready to wish New Year to New Horizons.

https://www.popsci.com/megapixels-nasa-asteroid-bennu Source:   By Jillian Mock, Popular Science. Excerpt: On Monday, a NASA spacecraft reached the near-Earth asteroid Bennu, kicking off a research mission that could help us unlock secrets of the early solar system and, hopefully, the start of life on Earth. The spacecraft, named OSIRIS-REx (because Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer doesn’t exactly roll off the tongue), has been beaming pictures of its approach to the asteroid all the way, allowing us to get a really close look for the first time. ...After a two year journey traveling to reach the asteroid’s orbit between Earth and Mars, the spacecraft is now less than 12 miles from Bennu. Following a few initial passes to get a sense of spin, mass, and shape, OSIRIS-REx will drop in close enough to start orbiting the asteroid in its weak field of gravity. If this happens as planned in January 2019, Bennu will become the small...

https://www.sciencemag.org/news/2018/10/after-visits-vesta-and-ceres-asteroid-exploring-dawn-spacecraft-about-go-dark Source:   By Paul Voosen, Science Magazine. Excerpt: ...After several missed attempts to communicate with Dawn over the past 2 days, NASA declared that the spacecraft had run out of hydrazine and reached the end of its mission. ...[original coverage from 17 October]: ...After an 11-year journey to Vesta and Ceres, the asteroid belt's two largest members, NASA's Dawn spacecraft ... gave a close-up view of how the presence or absence of water can shape asteroids, will remain tumbling in orbit around Ceres for decades before ultimately crashing into it. Launched in 2007, Dawn is the only NASA mission to orbit two planetary bodies, a feat made possible by its efficient ion thrusters. In 2011, it arrived at the egg-shaped, 600-kilometer-long Vesta, orbiting for a year before departing for Ceres, where it arrived in 2015. ...The two asteroids, which together accou...

https://www.sciencemag.org/news/2018/09/cosmic-conundrum-disks-gas-and-dust-supposedly-form-planets-don-t-seem-have-goods Source:   By Adam Mann, Science Magazine. Excerpt: Astronomers have a problem on their hands: How can you make planets if you don’t have enough of the building blocks? A new study finds that protoplanetary disks—the envelopes of dust and gas around young stars that give rise to planets—seem to contain orders of magnitude too little material to produce the planets. “This work is telling us that we really have to rethink our planetary formation theories,” says astronomer Gijs Mulders of the University of Chicago in Illinois, who was not involved in the research. ...The brightness of radio waves emitted by dust in the disk can be used to give a reasonable estimate of its overall mass. ...In the new study, astronomers led by Carlo Manara of the European Southern Observatory in Munich, Germany, used [Atacama Large Millimeter Array (ALMA)] to compare the masses of...