NASA Commercial Crew Program Blog 3 Aug 2018, 15:01 UTC NASA’s Commercial Crew Program is working with the American aerospace industry as companies develop and operate a new generation of spacecraft and launch systems designed to carry crews safely to and from low-Earth orbit. The Starliner and Crew Dragon will launch American astronauts on American-made spacecraft from American soil to the International Space Station for the first time since NASA retired its Space Shuttle Program in 2011.
Centauri Dreams 3 Aug 2018, 11:01 UTC I am glad to have the opportunity to formally introduce myself and give a summary of the recent work on planetary habitability and the habitable zone. I define the habitable zone (HZ) as the circular region around a star(s) where standing bodies of liquid water could exist on the surface of a rocky planet . The inclusion of the phrase “standing bodies of water”excludes dry worlds that may exhibit small outpourings of seasonal surface water (e.g. possibly Mars). Defined this way, the HZ is properly focused for detecting worlds that have large surface bodies of water (e.g. seas, big lakes, oceans) that are in direct contact with the atmosphere. If life is present on such a world, potential atmospheric biosignatures could be detected with current technology. However, in the absence of such large water bodies, life would not be detectable even if it were present. Likewise, although life may be possible within the seas of a Europa or Enceladus exoplanetary analogue, the global ice layer covering their oceans would prevent the detection of such subsurface life. Such observational issues keep the HZ within an orbital region that is placed somewhat closer to the star.
ESO Blog 3 Aug 2018, 10:00 UTC In May 2018, the star S2 made its closest approach to the black hole at the centre of the Milky Way. Observing this event was no easy task. The centre is full of dense dust clouds, impenetrable at visual wavelengths. The unique instruments GRAVITY and SINFONI, able to take highly precise measurements, needed to be developed for these observations. Frank Eisenhauer, a member of the Galactic Centre group at Max Planck Institute for Extraterrestrial Physics and principal investigator for GRAVITY and SINFONI, talks about observing the close approach of S2 in the second of a three blog post series.
Astronotes 3 Aug 2018, 08:30 UTC Early in the morning – a little after 7am local time – in the plains of central Siberia populated only by a handful of natives and some Russian settlers, “the sky split in two and fire appeared high and wide over the forest. The split in the sky grew larger, and the entire northern side was covered with fire.” This is an account from an eyewitness who was at Vanavara trading post, some 65 km (40 miles) south of the epicentre. He went on to say that his shirt felt as if it were on fire, the ground shook, and shortly afterwards a great blast pushed him off his chair and threw him a few metres away. Soon after, a hot rushing wind came, “which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn, a part of the iron lock snapped.”
American Meteor Society 3 Aug 2018, 07:02 UTC The Perseids are often the most impressive Meteor Shower of the year for the Northern Hemisphere. The Perseids offers a consistently high rate of meteors every year and it occurs in August when the temperatures are usually nice enough for a night under the stars!
Planetaria 3 Aug 2018, 02:16 UTC Could there have been life on the Moon in the distant past? Our airless, mostly dry moon certainly isn’t the firstplace that comes to mind when it comes to searching for life elsewhere. Today, its radiation-blasted surface is inhospitable to life as we know it. Plus the Moon has no air or liquid water. But what about a few billion years ago? An article published by scientists in the journal Astrobiology – and announced by Washington State University on July 23, 2018 – brings together the various lines of evidence for a once-habitable moon and concludes that there might have been not one but two habitable periods early in the moon’s history.
astrobites 2 Aug 2018, 17:41 UTC Cosmic cannibalism is incredibly common — we believe that all large galaxies grew through mergers with smaller galaxies. Our own Milky Way is guilty of eating its smaller siblings and will continue to do so, possibly consuming the Large and Small Magellanic Clouds at some point billions of years in the future. Our closest neighbor galaxy and the largest galaxy in the Local Group, Andromeda, will also eventually consume us! (Luckily, we’ll be long gone by the time that happens in about 4 billion years.) However, today’s paper isn’t about future mergers of galaxies in our Local Group. Instead, it discusses a significant past merger event between Andromeda (aka M31) and what used to be the third-largest galaxy in the Local Group, M32.
Starts With a Bang! 2 Aug 2018, 14:01 UTC Imagine I told you that everything you ever saw, touched, or experienced — in this world and in the Universe beyond — was just a tiny fraction of the matter that’s out there. That for every particle of normal matter that existed, there was at least five times as much, mass-wise, of a new form of invisible matter that we’ve never directly detected. And that beyond that, the Universe also contained a mysterious form of energy that caused distant galaxies to suddenly speed up and accelerate away from us some six billion years ago. When all was said and done, all the normal stuff was just 5% of the grand total. You’d wonder if we didn’t have something fundamentally wrong. If we hadn’t goofed something fundamental, like our theory of gravity. This is the heart of the debate over the existence of dark matter. But before you pick a side, tempting though it is, let’s think about the problem.