This week in space from Fraser Cain | | I'm writing this newsletter on March 30, and from what we can tell, the Chinese Tiangong-1 station is going to return to Earth on Sunday, April 1st, 2018, give or take a day or so.
Right now, we don't know anything more accurately than that, which means that it could return to Earth anywhere within its orbital track from 45-degrees north or south. Most likely, it'll go into the oceans, since that's what's covering most of Earth's surface.
Right now, the orbital height is approximately 200 km, but it's losing altitude with each successive pass, getting closer and closer to Earth. But the Earth is an oblate spheroid, not a perfect sphere, so that altitude over the planet can change by 10 kilometers depending on whether it's over the equator or higher latitudes.
All we can do is wait and watch, and hopefully estimates will get better as it gets closer to Earth. I'd like to direct you do a few resources that'll be helpful to track its position. I've really enjoyed using Satflare and the Aerospace Corporation, with their regular updates, as well as Heavens Above, which gives a life ground track.
Stay tuned. Hopefully someone will get a chance to see the station as it tears up in the atmosphere, it should be spectacular to see.
Fraser Cain
Publisher
Universe Today
As always, if you have comments or questions, or suggestions on how I can improve this newsletter, please don't hesitate to reply this email or send me an email at frasercain@gmail.com. | | 
About 4 billion years ago, Mars was a much warmer and wetter place, with liquid water covering much of its surface. It now looks like it had oceans earlier than anyone believed thanks to its raging early volcanism.
Astronomers have found that there's 10x as much dark matter as regular matter in the Universe. So it was extremely surprising to discover a relatively nearby galaxy with nearly no dark matter in it at all.
For folks in the Southern Hemisphere, the Large and Small Magellanic Clouds are familiar features in the night sky. One of these dwarf galaxies is tearing material off the other into a long tidal tail, but astronomers have had trouble figuring out which was feeding, and which was the victim. Until now.
China is one of the top launch providers in the world, and they're constantly advancing in the capabilities of their rockets and the kinds of missions they're sending up to space. China recently tested the engines of their Long March 9, a super heavy rocket that would help send crewed missions to the Moon and beyond.
SETI has been scanning the sky looking for signals from extraterrestrials. But another method might work as well: looking for the telltale signature of their satellites passing in front of their stars. Aliens could build artifacts orbiting their stars that give a very specific and unusual signal that should be obvious from here on Earth.
Remember the interstellar asteroid Oumuamua? Of course you do, we won't shut up about it. Astronomers have worked out the kinds of gravitational interactions that must have been required to throw and asteroid like Oumuamua out into deep space, and calculated that the vast majority would occur in binary and other multiple star systems.
We're now learning that icy worlds seem to be the best places in Solar System where life could be hiding. Worlds like Europa and Enceladus, which have vast oceans of liquid water beneath a shell of water ice. It turns out NASA designed a mission that could get down through the ice shell and sample the water below, searching for life.
I know, you're shocked. Shocked! NASA announced this week that the launch of James Webb is going to be delayed until 2020. The final decision came from the project's Standing Review Board, which decided that it was going to need additional tests before it was ready to fly.
I love this illustration of various heavy lift vehicles, from the Space Shuttle to the Interplanetary Transport Spaceship. You can really see how much smaller the Big Falcon Rocket ended up being from their original design. It'll be amazing to see when these things start flying.
I know it just seems like yesterday, but NASA's Curiosity Rover just passed 2,000 days on the surface of Mars. During its time on Mars, the hardworking rover has found methane and organic molecules, helped discover how it lost its atmosphere, and how it used to have water in the past.
Astronomers watching KIC 846852 have noticed that it's dropping in brightness again. In fact, this mysterious star has experienced its greatest drop in brightness since it was first observed by Kepler back in 2013. Astronomers now know the star is partly obscured by dust, and this new dimming is helping characterize what's going on around it. Other Interesting Space Stuff
Amazing Astrophotography
Check out this fantastic image of the Milky Way, arching over the great Ausangate Mountain. This photo was taken by Sergio Vindas, an astrophotographer based in Costa Rica. Epic!
We feature a different astrophotographer every day on our Instagram page. Want to do a takeover? Use the hashtag #universetoday and I'll check out your photos. | | | |
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