Showing posts from March, 2019

66 million-year-old deathbed linked to dinosaur-killing meteor Source:   By Robert Sanders, Berkeley News, UC Berkeley. Excerpt: The beginning of the end started with violent shaking that raised giant waves in the waters of an inland sea in what is now North Dakota. Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills. The heaving sea turned into a 30-foot wall of water when it reached the mouth of a river, tossing hundreds, if not thousands, of fresh-water fish — sturgeon and paddlefish — onto a sand bar and temporarily reversing the flow of the river. Stranded by the receding water, the fish were pelted by glass beads up to 5 millimeters in diameter, some burying themselves inches deep in the mud. The torrent of rocks, like fine sand, and small glass beads continued for

Fossil Site Reveals Day That Meteor Hit Earth and, Maybe, Wiped Out Dinosaurs. Source:    By William J. Broad and Kenneth Chang, The New York Times.  Excerpt: Sixty-six million years ago, a giant meteor slammed into Earth off the coast of modern-day Mexico. Firestorms incinerated the landscape for miles around. Even creatures thousands of miles away were doomed on that fateful day, if not by fire and brimstone, then by mega-earthquakes and waves of unimaginable size. Now, scientists have unearthed a remarkable trove of fossils that appear to date from the very day of the impact. The burial site consists of more than four feet of sediments and organic remains that were dumped in North Dakota almost instantly and transformed into rock over the eons. It evidently captures, in unparalleled detail, the repercussions of the giant doomsday rock.... ...When the meteor smashed into waters near what is now Mexico’s Yucatán Peninsula, it left a giant crater known as Chicxulub and prompted uphe

The Asteroid Was Shooting Rocks Into Space. ‘Were We Safe in Orbit?’ Source:  By Kenneth Chang and Shannon Stirone, The New York Times. Excerpt: HOUSTON — The asteroid Bennu, with the shape of a spinning top, turns out to be extremely rugged. That is going to make it difficult for a NASA spacecraft, Osiris-Rex, to vacuum up a sample to take back to Earth. It was designed to collect sand and gravel, not boulders. In addition, Bennu is shooting back. “We are seeing Bennu regularly eject material into outer space,” said Dante Lauretta, Osiris-Rex’s principal investigator.... The NASA spacecraft, which launched in 2016, entered orbit around Bennu on Dec. 31. It is not the only spacecraft from Earth exploring an asteroid. Hayabusa2, launched by Japan’s space agency in 2014, began orbiting the asteroid Ryugu last year. Its mission is also to collect samples for return to our planet for study, .... Both missions have found that the objects they are studying have terrain much more jagged

How Ultima Thule Is Like a Sticky, Pull-Apart Pastry 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 sim

Untouched moon samples from the Apollo missions will be studied for the first time Source:   By Ashley Strickland, CNN. Excerpt: After sitting untouched in storage for nearly 50 years, lunar samples collected during the Apollo 15, 16 and 17 missions will be studied for the first time, NASA Administrator Jim Bridenstine announced Monday. ...NASA selected nine teams to study the moon samples and awarded a total of $8 million for their research. "By studying these precious lunar samples for the first time, a new generation of scientists will help advance our understanding of our lunar neighbor and prepare for the next era of exploration of the Moon and beyond," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, in a statement. ...The three samples from the final three Apollo missions have never been exposed to our atmosphere on Earth. Six of the nine teams will study the Apollo 17 sample, delivered to Earth in a vacuum-sealed drive tub

The first planet Kepler spotted has finally been confirmed 10 years later Source:   By Lisa Grossman, Science News. Excerpt: A decade after being found, the first exoplanet candidate spotted by the Kepler space telescope has been confirmed as a real world. The planet orbits a star initially dubbed KOI 4, for Kepler Object of Interest 4 (KOIs 1 through 3 were known before Kepler launched in March 2009). ...The Kepler team originally thought the star was about 1.1 times the width of the sun, which would make the planet about the size of Neptune. But then astronomers saw a second dip in starlight as the world passed behind the star, called a secondary eclipse. That second dip shouldn’t be visible for such a small planet, so the exoplanet candidate was dismissed as a false alarm. ...KOI 4 is actually about three times the width of the sun, meaning its planet would be about three times as large as first estimated — or a bit larger than Jupiter, the team found. That’s big

There’s probably another planet in our solar system. Source:   By MIT Technology Review. Excerpt: When it comes to exploring the solar system, astronomers have an embarrassing secret. Despite 400 years of stargazing, they have discovered only two large objects that would have been unknown to the ancients: Uranus in 1781 and Neptune in 1846. That’s not for lack of trying. The possibility of an unknown planet just beyond observational reach has attracted astronomers like moths to a flame. A few have been successful. Several astronomers together discovered Neptune after noticing that the other planets were being gravitationally nudged by an unknown mass. Neptune didn’t entirely resolve these discrepancies, and the hunt continued into the 20th century, culminating in Pluto’s discovery in 1930. But Pluto turned out to be so small that it couldn’t account for the nudging. Indeed, it was later humiliatingly demoted to a “dwarf planet.” ...  

Life probably exists beyond Earth. So how do we find it? Source:  By Jamie Shreeve, Spencer Lowell, Dana Berry, National Geographic  Excerpt:  Sara...Seager, 47, is an astrophysicist. Her specialty is exoplanets, namely all the planets in the universe except the ones you already know about revolving around our sun. On a blackboard, she has sketched an equation she thought up to estimate the chances of detecting life on such a planet. Beneath another blackboard filled with more equations is a clutter of memorabilia, including a vial containing some glossy black shards. ...When Seager entered graduate school in the mid-1990s, we didn’t know about planets that circle their stars in hours or others that take almost a million years. We didn’t know about planets that revolve around two stars, or rogue planets that don’t orbit any star but just wander about in space. In fact, we didn’t know for sure that any plan