Universe Today – How did supermassive black holes get so… well, supermassive… in the early Universe, when seemingly not enough time had yet passed for them to accumulate their mass through steady accretion processes alone?
Astronomers now estimate that about one in five sun-like stars in our galaxy has an Earth-sized planet in the habitable zone. Credit: UC Berkeley
“Nextbigfuture – Based on a statistical analysis of all the Kepler observations, astronomers at UC Berkeley and University of Hawaii, Manoa now estimate that one in five stars like the sun have planets about the size of Earth and a surface temperature conducive to life.
Given that about 20 percent of stars are sun-like, the researchers say, that amounts to several tens of billions of potentially habitable, Earth-size planets in the Milky Way Galaxy.
Nextbigfuture – Tom McKendree is now working at Raytheon and has an updated analysis of solar electric ion engines using different levels of molecular nanotechnology (none, simple, complex and advanced)
Nextbigfuture – Three large, near-Earth asteroids, two of which measure about 12 miles in diameter — are the largest near earth asteroids to have been discovered in 23 years. The smallest of the three asteroids measures little more than a mile across, but it may pass within 3.4 million miles of Earth, making it a “potentially hazardous asteroid.”
When an asteroid exploded over the Russian city of Chelyabinsk in February, shattering windows for miles and injuring well over 1,000 people, experts said it was a rare event — of a magnitude that might occur only once every 100 to 200 years, on average. But now a team of scientists is suggesting that the Earth is vulnerable to many more Chelyabinsk-size space rocks than was previously thought. In research being published Wednesday by the journal Nature, they estimate that such strikes could occur as often as every decade or two