Exilian
Art, Writing, and Learning: The Clerisy Quarter => History, Science, and Interesting Information - The Great Library => Topic started by: Glaurung on August 06, 2014, 11:29:06 PM
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As you might have heard, the Rosetta space probe arrived at its target (comet 67P/Churyumov-Gerasimenko) today, after a ten-year journey to get it into the right orbit - see this BBC news article (http://www.bbc.co.uk/news/science-environment-28659783). I'm looking forward to the science reports, and also to finding out what the surface of a comet actually looks like.
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I naively expected it to be a round blob, but it's far more fun that it's the shape it is, if only to hear reporters describe it as the 'space duck'!
Also, harpoons. Gotta love harpoons.
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Space! Yay!
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Another BBC article (http://www.bbc.co.uk/news/science-environment-28671805), with a selection of pictures, some very detailed.
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(http://i.imgur.com/s6bjPGC.gif)
quite a spectacular orbit
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Indeed, and likewise what it's had to do to get out to the comet: five times round the sun, and several gravitational slingshots. All with a fixed amount of fuel and fairly limited margin for error. This is rocket science!
EDIT: This xkcd post (http://www.xkcd.com/1356/) seems relevant.
Edit 2: As does this one (http://www.xkcd.com/1402/).
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(http://i.imgur.com/s6bjPGC.gif)
Go home probe, you're drunk.
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Pfft, I can do that! :P
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Some more BBC news (http://www.bbc.co.uk/news/science-environment-29036303) about Rosetta: ESA are about to start shrinking its orbit around the comet, and are evaluating potential landing sites. They're having "some headaches" in finding the centre of mass! They're also still working on a naming system for surface features.
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Well the ESA have managed to land on a comet, with a harpoon. No idea if it'll end up being worthwhile, but hey, pretty cool.
Moderation note: I moved this post from "Space yays" to this more specific thread; apologies if this has confused anyone.
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Alas, the harpoons didn't fire, and nor did the thruster rocket. Philae bounced several times, and is now thought to be well away from its intended location. Worse, it's in the dark much of the time, so its batteries won't recharge, and it's currently expected to run out of power on Saturday :(
Details are from a somewhat jumbled BBC news article (http://www.bbc.co.uk/news/science-environment-30034060); no doubt there's much more on the ESA website and elsewhere.
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This would be the most relevant xkcd :P http://www.xkcd.com/1446 (http://www.xkcd.com/1446)
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Back to 67P, we now have pictures of the landing bounce:
http://www.bbc.co.uk/news/science-environment-30083969
(http://news.bbcimg.co.uk/media/images/79086000/jpg/_79086634_79081268.jpg)
Repost of my last science bit before the storm broke.
This area is now re-consecrated to only being about the comet & lander. Please take discussion of the shirt to discussion and debate where it will happily or unhappily rage on.
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Some news on science results from Rosetta: the isotope distribution (specifically hydrogen vs. deuterium) in the comet's water is quite different from that on Earth. This suggests that comets were not the source of the Earth's water, or at least not the particular group of comets that 67P comes from. More in a BBC News article (http://www.bbc.co.uk/news/science-environment-30414519), including a link to the original paper in Science.
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Some further news from Rosetta: the comet has been photographed in colour for the first time (strictly, a composite of monochrome pictures with colour filters). it turns out to look just like it did in the previous monochrome pictures - i.e. it's a very uniform grey. In fact it's more or less black, as the images have been brightened considerably to show detail. More information in a BBC News article (http://www.bbc.co.uk/news/science-environment-30454342).
One effect of this is that the comet will be a good absorber of solar energy. I assume Rosetta has some means of determining surface temperature, because it'll be very interesting to see how the comet warms up as it approaches the sun.
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it turns out to look just like it did in the previous monochrome pictures - i.e. it's a very uniform grey.
I feel for the people who'd been working on that. Yeah it's a result and gives interesting data, but when you get a negative result like that there's always a feeling of 'ah nuts'
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There's some more news and good-quality pictures from Rosetta, as reported by the BBC (http://www.bbc.co.uk/news/science-environment-30931445). About 70% of the surface has now been imaged to a resolution of about a metre, revealing features that include "goosebumps" and dunes or ripples. The comet also seems to be be very low density for its size, but there's no information yet on whether it's just fluffy, or has big holes inside.
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More news from comet 67P. It's warming up - daytime temperatures are currently getting up to a balmy -43C. Consequently it's now emitting jets of gas, at speeds up to 800 m/s, and extending several km from the surface.
This has two effects:
- First, it's slowing the comet's rotation by about a second a day. This was detected when Rosetta's "navigators" at ESA found they were not seeing expected landmarks at quite the time they expected.
- Second, there's now enough gas in the space around the comet that Rosetta (with 64 sq m) of solar panels) gets blown around if it comes too close. It has had to retreat from a gravitationally-bound orbit within 30 km to a powered orbit no closer than 70 km.
All this from (as usual) a BBC New article (http://www.bbc.co.uk/news/science-environment-31965458).
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And another dollop of cometary news, as usual via the BBC (http://www.bbc.co.uk/news/science-environment-32298516).
Data from Rosetta and Philae shows that the comet has no magnetic field. This is interesting because it implies that magnetic fields did not play a part in the formation of comets in the early solar system.
There's more information in a Science paper (http://www.sciencemag.org/content/early/2015/04/13/science.aaa5102) (subscription needed).
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It's been quite a while since I posted on this thread. Data and pictures keep coming back, and news stories pop up now and then. This one (http://www.bbc.co.uk/news/science-environment-33720951) (BBC again) is about some data from the lander, Philae. It was programmed to have a "sniff" of the gases around it ten minutes after landing, and it duly did so, even though it was bouncing well above the surface at the time. The results were sent back before Philae shut down, and have now been analysed and published. There's an interesting range of small organic molecules, including ones containing oxygen or nitrogen; some have never been detected on comets before. One of the researchers used the phrase "a frozen primordial soup".
For those less interested in the chemistry, the article also has some nice pictures, one of which looks to have been taken at or very near the surface.
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Time flies: I hadn't thought it was over a year since I last posted in this thread. Anyway, Rosetta is still going around the comet - it's now in a very close orbit as the comet is no longer spewing out gas and dust. It can therefore get much higher resolution images of the surface, and so it's managed to find the Philae lander. As expected, it's in a dark hole, on its side.
Rosetta itself will end up on the comet too, quite soon - it's due to impact on 30 September, returning data as it closes in.
All this and some pictures in the inevitable BBC News article (http://www.bbc.co.uk/news/science-environment-37276221).
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Today is impact day - in fact in about 10 minutes, as I write. The comet is over 700 million km away, so we don't get confirmation for another 40 minutes after that.