Starts With a Bang! 23 Aug 2019, 14:01 UTC One of the most terrifying prospects here on Earth is that of our planet being struck by a large, massive, fast-moving asteroid or comet. Even a modest fragment of such an object can strike Earth with such force that devastation will surround the impact site. If the strike deposits enough energy in the right location, like the Chelyabinsk (above) event from 2013 or the Tunguska event of 1908 could have, millions could die and many billions of dollars in property damage could occur. The impact on Earth from even larger strikes, such as the event which created Barringer Crater or — even more catastrophically — the impactor that caused Chixulub crater some 65 million years ago, can still be measured today. Still, all the violence that Earth has experienced is nothing compared to what Jupiter, the most impacted object in the Solar System goes through. We all got a reminder of this on August 7, 2019.
Centauri Dreams 22 Aug 2019, 16:09 UTC Impacts seem to have run rampant in the early Solar System, to judge from what we keep uncovering as we survey today’s evidence. The Moon is widely considered to be the result of Earth’s impact with a Mars-class object, while Mercury’s big iron core may show what happens when a larger world is stripped of much of its mantle in another ‘big whack.’ Then there’s Uranus, spinning lopsidedly in the outer system.
Starts With a Bang! 22 Aug 2019, 14:01 UTC Back in February of 2016, LIGO made an announcement that changed our picture of the Universe forever: from more than a billion light-years away, two massive black holes, of 36 and 29 solar masses, had inspiraled and merged. The result of that merger was a single black hole of 62 solar masses, with the remaining 3 solar masses converted into pure energy via Einstein’s E = mc², rippling throughout the Universe in the form of gravitational waves. Since that time, LIGO has risen into the double digits with the number of detections it’s made, as gravitational waves are now undoubtedly real and teaching us an incredible amount about our Universe. But all of this is still information about our Universe according to our classical theory of gravity: General Relativity. If quantum physics is right, then wave-particle duality is real, even for gravitational waves. Here’s what that means.
Scientific American 22 Aug 2019, 10:45 UTC Thirty years after a probe visited Neptune, many scientists say now is the time to finally return to that world and Uranus
Scientific American 21 Aug 2019, 16:00 UTC It could be possible, at least to some degree, with a novel system involving aerogel
Many Worlds 21 Aug 2019, 15:13 UTC How many habitable worlds like our own could exist around other stars? Since the discovery of the first exoplanets, the answer to this question has seemed tantalizingly close. But to estimate the number of Earths, we first need to understand how our planet could have gone catastrophically awry.
Bad Astronomy 21 Aug 2019, 13:00 UTC The Earth has a magnetic field, in many ways similar to a bar magnet. Hopefully you played with a bar magnet in school. You sprinkle iron filings on a piece of paper and put the magnet underneath and the iron shavings rearrange themselves into a lovely set of curves, converging at the magnetic poles and spreading out more halfway between them. The overall shape is like an apple cut in half. The Earth has a magnetic north pole and a magnetic south pole (not to be confused with the geographic, or rotational, poles) just like that bar magnet — we call this a dipole field. But the mechanism creating the magnetic fields between the two are way different.
NASASpaceFlight.com 20 Aug 2019, 18:08 UTC NASA’s plans to land both robots and humans on the moon have taken several steps forward. A solicitation for scaled-up robotic landers has been released by the Commercial Lunar Payload Services program, and plans for human moon landers have changed to make room for more innovation by private partners. NASA will be supporting the development of these vehicles with new partnerships, aiming to mature technologies for both Moon and Mars missions.
Centauri Dreams 20 Aug 2019, 14:17 UTC These days we have a keen interest in small red dwarf stars (M-dwarfs) not only because they’re ideal for study, with deep transits of worlds in their habitable zones and the prospect of future analysis of their atmospheres, but also because they are so plentiful. Comprising perhaps 80 percent of all stars, they may well be home to the great majority of planets in the galaxy. And while they are common, they’re also long-lived, so that life would have plenty of opportunity to develop.