Astro Bob 20 Jun 2018, 17:37 UTC The Japanese asteroid sample return mission Hayabusa 2, which launched in December 2014, is pulling up to its target this week, the asteroid Ryugu. The asteroid, about a half-mile (900 meters) across, is shaped like a spinning top with several prominent craters and an equator-girdling ridge. The probe is still closing into Ryugu. In the last 12 hours it’s entered its gravity field earlier today stands just under 60 miles (~100 km) from the asteroid. It will arrive at its “home” location of 12.5 miles (20 km) from which it will begin its survey of Ryugu later this month.
Centauri Dreams 20 Jun 2018, 14:56 UTC Once we have a firm exomoon detection, we can begin to characterize the possibilities. As we await improvements in our technology, deepening our knowledge of potential exomoon host planets is the best we can do, and that would begin, as this paper suggests, with radial velocity follow-up observations on gas giant habitable zone candidates like the ones compiled by the authors.
Starts With a Bang! 20 Jun 2018, 14:01 UTC There are few things in the Universe that are as easy to form, in theory, as black holes are. Bring enough mass into a compact volume and it gets more and more difficult to gravitationally escape from it. If you were to gather enough matter in a single spot and let gravitation do its thing, you’d eventually pass a critical threshold, where the speed you’d need to gravitationally escape would exceed the speed of light. Reach that point, and you’ll create a black hole.
Air & Space Magazine 19 Jun 2018, 18:49 UTC Saturn’s large moon Titan remains the most exotic planetary body we know of. There is no other place quite like this. Hydrocarbon lakes are common on the surface, replenished by occasional methane downpours from an atmosphere consisting of nitrogen and methane. In many ways, the moon’s thick haze is not very unlike the early atmosphere of Earth.
Scientific American 19 Jun 2018, 16:30 UTC When two wormholes collide, they could produce ripples in space-time that ricochet off themselves. Future instruments could detect these gravitational “echoes,” providing evidence that these hypothetical tunnels through space-time actually exist, a new paper suggests.
Starts With a Bang! 19 Jun 2018, 14:01 UTC We know what our Solar System looks like today, but one of science’s greatest mysteries is how it formed and grew up to be the way it is right now. There are some general pieces we know must be true from a variety of astronomical observations. Like all star systems, ours formed from a collapsing cloud of molecular gas. Like all stars with planets, our young proto-star formed a protoplanetary disk that grew into planets, asteroids, and the Kuiper belt. From simulations, we know that many bodies were ejected, accreted, and absorbed over time. But 4.5 billion years on, we don’t have remnants of what our Solar System was like at the time of its birth. In the great gravitational dance taking place in our cosmic backyard, we cannot know what our full history was. All we have left are the survivors. But for the first time, those survivors likely include something left over from our protoplanetary dawn: interplanetary dust particles. For the first time, we can truly learn where we came from.
Astro Bob 18 Jun 2018, 22:11 UTC Venus met up with the crescent moon over the weekend. Tonight through Wednesday, it gets cozy with the Beehive star cluster in Cancer the Crab. To see it you have to wait until later in twilight when Venus will be rather low in the western sky and use binoculars. Focus on Venus and look to its left for the star cluster.
Planetaria 18 Jun 2018, 19:58 UTC With the discovery of thousands of exoplanets orbiting other stars, the search for life elsewhere has entered an exciting new phase. So far, most of these worlds have been found many light-years away (largely due to the fact that the Kepler Space Telescope, which has discovered the majority of them so far, has focused on a specific patch of sky which contains very distant stars). But what about closer stars? Including, of course, Alpha Centauri, the closest star system to our Sun, only just over four light-years away. According to Tom Ayres of the University of Colorado Boulder: “Because it is relatively close, the Alpha Centauri system is seen by many as the best candidate to explore for signs of life. The question is, will we find planets in an environment conducive to life as we know it?”