Centauri Dreams 8 Aug 2017, 16:24 UTC Some people tell me that the dangers posed by an asteroid or comet impact on Earth are over-publicized. Surely whatever object hits us would land some place harmless, causing nothing but a flurry of news stories. Others remind me that Chelyabinsk was seriously rattled by the explosion of a small asteroid in 2013, an event that could have created appalling damage with a slight deviation in trajectory. My own view is that guessing at the odds doesn’t do much for us. I favor a strong research effort into asteroid deflection and risk mitigation strategies.
Scientific American 8 Aug 2017, 11:30 UTC The possible discovery of a giant extrasolar moon suggests our own may be an anomaly -- Read more on ScientificAmerican.com
Air & Space Magazine 7 Aug 2017, 21:00 UTC In a recent paper published in Scientific Reports, David Sloan of the University of Oxford and colleagues analyzed three different scenarios in which all life on Earth could be extinguished: large asteroid impacts, supernova explosions, and the cataclysm resulting from a gamma-ray burst. The most likely killing mechanism in all three cases is heat and radiation—particularly the boiling away of the planet’s oceans, which would exterminate all surface and underwater life. For an Earth-like planet, the authors calculate an overall chance of complete sterilization as being less than one in a million over a time period of a billion years. In other words, it’s very unlikely for life to be completely extinguished on a habitable planet, at least in these three scenarios.
Many Worlds 7 Aug 2017, 19:36 UTC The main asteroid belt of our solar system — with almost two million asteroids a kilometer in diameter orbiting in the region between Mars and Jupiter. There are billions more that are smaller. New research has identified the “family” of a primordial asteroid or planetesimal, one of the oldest ever detected.
Cosmic Diary 7 Aug 2017, 17:39 UTC The large dunes in the middle of this 375×450 m (0.23×0.28 mi) scene run along a valley (the small dunes at top and bottom are on high ground). What’s amazing about this is that the ends of the large dunes extend into the valley walls. That is, they’re covered by the stuff in the valley walls. Usually dunes sit on top of all the other geologic structures, but not here. These dunes formed a long time ago. And then a lot of sediment piled on top of them – but without destroying them (which is what usually happens on Earth, so we don’t see this sort of thing here). And then those sediments were later eroded to make the 0.5 km wide valley, revealing the buried dunes. Look at all this geology we can do from space!
io9 Space 7 Aug 2017, 13:00 UTC As everyone is undoubtedly aware by this point, on August 21st, folks across the country will be able to see a total solar eclipse—the first one visible coast-to-coast in nearly a century. The whole shebang will last about two minutes and 40 seconds at its longest, which is cool but kind of meh in the grand scope of solar eclipses throughout history. In 2009, for example, a solar eclipse visible in Southeast Asia set the record for the longest one of the century so far, lasting six minutes and 40 seconds.