Showing posts from June, 2017

Greetings, E.T. (Please Don’t Murder Us)

Source:   By Steven Johnson, The New York Times. Excerpt: On Nov. 16, 1974, a few hundred astronomers, government officials and other dignitaries gathered in the tropical forests of Puerto Rico’s northwest interior, a four-hour drive from San Juan. The occasion was a rechristening of the Arecibo Observatory, at the time the largest radio telescope in the world. The mammoth structure — an immense concrete-and-aluminum saucer as wide as the Eiffel Tower is tall, planted implausibly inside a limestone sinkhole in the middle of a mountainous jungle — had been upgraded to ensure its ability to survive the volatile hurricane season and to increase its precision tenfold. To celebrate the reopening, the astronomers who maintained the observatory decided to take the most sensitive device yet constructed for listening to the cosmos and transform it, briefly, into a machine for talking back. ...the public-address system blasted nearly three minutes of two-tone noise through the muggy afternoon

Could Asteroids Bombard the Earth to Cause a Mass Extinction in 10 Million Years?

Source:   By Sanna Alwmark, Matthias Meier, Scientific American Excerpt: Given the evidence that an asteroid triggered the dinosaur extinction, it makes sense to ask whether showers of asteroids could be to blame for regular extinction events....

Solving the Scorching Mystery of the Sun’s Erupting Plasma Jets

Source:   By Nicholas St. Fleur, The New York Times Excerpt: Spiky bursts of plasma called spicules swirl around the surface of the sun. Millions erupt every moment, spurting solar material some 6,000 miles high at speeds of about 60 miles per second. “These things are very violent,” said Bart De Pontieu, a research scientist with Lockheed Martin Solar and Astrophysics Lab in Palo Alto, Calif. “The gas in spicules is about 10,000 degrees and they travel the length of California in just a minute or so.” Scientists have studied spicules for decades, but were not sure how the plasma jets formed. Now, Dr. De Pontieu and his colleagues think they have solved the searing mystery. They published their findings Thursday in the journal Science. ...they created a computer simulation that reconstructed the conditions between the sun’s surface and its atmosphere, where spicules form. Powerful magnetic fields are created in the interior of the sun. There, the high density keeps them tangled an

Ten Earth-Sized Planets Found by Exoplanet-Hunting Telescope

Source:   By JoAnna Wendel, Earth & Space Science News, EoS, AGU Excerpt: NASA introduced 219 exoplanet candidates to the world on Monday. Ten of these are roughly Earth sized and orbit their stars in the so-called habitable zone, a distance at which temperatures could be ripe for liquid water. The candidate exoplanets appear in the eighth and newest catalog from the agency’s exoplanet-hunting Kepler space telescope and the final catalog from Kepler’s observations of the Cygnus constellation. The new catalog includes 4034 exoplanet candidates overall. Past “Kepler catalogs have shown us that small exoplanets are common,” Susan Thompson, lead author on the catalog study and a research scientist at the SETI Institute in Mountain View, Calif., told Eos. “With this [latest] catalog, we can show whether this is also true for exoplanets that are in orbital periods similar to those of the Earth.” Accompanying research also reveals that the majority of known exoplanets fall into two d

Earth-Size Planets Among Final Tally of NASA’s Kepler Telescope

Source:   By Dennis Overbye, The New York Times 2017-06-19. . . For GSS A Changing Cosmos chapter 8. Excerpt: ...astronomers released a list on Monday of 4,034 objects they are 90 percent sure are planets orbiting other stars. The new list is the final and most reliable result of a four-year cosmic census of a tiny region of the Milky Way by NASA’s Kepler spacecraft. ... The catalog — the eighth in the endeavor — was released at a meeting of exoplanet astronomers here at the Ames Research Center that represents a last hurrah for the survey mission, which will end on Sept. 30. The space telescope itself is doing fine, and it has embarked on a new program of short-term searches called K2. Among other things, Dr. Batalha said, for the first time there is at least one planet, known as KOI 7711 (for Kepler Object of Interest), that almost matches the Earth, at only 30 percent wider and with an orbit of almost exactly one year. In all, there are 219 new planet candidates in the catalog.