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Space and Astronomy Thread |
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#2901 |
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Quote:
You seem to have missed the point. This is about water flowing on Mars NOW.
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#2902 |
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Quote:
No I have not because the discovery of saline waters leaving streaky trails in crater gullies is several years old (15 IIRC) and we know all this already. This press conference is just a higher profile rehash of what was already known about. Saline (thus having a lower freezing point) water with the salts originating from the Martian regolith was the cause then and it is the same cause now, i.e. no change and no new knowledge.
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#2903 |
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Quote:
I expect you'll be wanting to cite the relevant scientific papers from 15 years ago, complete with spectroscopic analysis...
That orbiter, and the European Space Agency's Mars Express probe, have both made a great contribution to the study and understanding of Mars. |
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#2904 |
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Join Date: Dec 2004
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Quote:
More likely, I expect I'll be telling you that there were plenty of peer-reviewed and published papers from 2002 onwards that were already elucidating the saline water cause of the streaks in gullies on Mars following the photos taken by NASA's Mars Global Surveyor in the summer of 2000.
Isn't the point that there was a lot of speculation about the cause, but not the compelling evidence which has now been found? Unless you really think that NASA are a bunch of clowns, of course. |
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#2905 |
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Quote:
And yet you haven't given me even one...
Isn't the point that there was a lot of speculation about the cause, but not the compelling evidence which has now been found? Unless you really think that NASA are a bunch of clowns, of course. |
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#2906 |
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Join Date: Dec 2004
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Quote:
Seek and ye shall find ------> http://www.jstor.org
However, I did not find that which I sought. Perhaps you could help? |
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#2907 |
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Join Date: May 2004
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And now for some astro news starting with a flocculent galaxy (yes, they really do exist!):
A new picture from the Hubble Space Telescope shows the spiral galaxy NGC 3521 in a shot that looks almost artificial in its painterly beauty. Discovered in 1784 by British astronomer William Herschel, the 40 million light-year distant object has what are called flocculent spirals, a softer version of the well-defined arms of other galaxies. Lord Foster's architectural partnership has come up with some interesting new ideas for a Mars base: http://www.dezeen.com/2015/09/25/fos...bots-regolith/ http://www.dailymail.co.uk/sciencete...ed-planet.html |
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#2908 |
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Latest images from Pluto's moon Charon http://www.nasa.gov/feature/pluto-s-...iolent-history
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#2909 |
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Quote:
Latest images from Pluto's moon Charon http://www.nasa.gov/feature/pluto-s-...iolent-history
![]() http://phenomena.nationalgeographic....h-a-dark-past/ http://www.bbc.co.uk/news/science-environment-34420062 Why all those posters of the Solar System are utter bollocks. http://phenomena.nationalgeographic....rong-till-now/ Remember that this is just the major Planets - the distance involved are utterly insignificant compared to what is beyond Neptune - the Kuiper Belt, Scattered Disc and all the way to the Oort cloud - it boggles the mind.
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#2910 |
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Inactive Member
Join Date: Jul 2009
Location: Taedet animam meam vitae
Posts: 40,368
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Quote:
Why all those posters of the Solar System are utter bollocks.
http://phenomena.nationalgeographic....rong-till-now/ Remember that this is just the major Planets - the distance involved are utterly insignificant compared to what is beyond Neptune - the Kuiper Belt, Scattered Disc and all the way to the Oort cloud - it boggles the mind. ![]()
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#2911 |
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Join Date: Feb 2014
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Quote:
Wow, loved it, loved it, loved it! What a beautiful film. Thanks for posting
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#2912 |
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The International Astronomy Show is still on in Warwickshire tomorrow Saturday 3rd October. So if you fancy looking at and possibly buying some serious astronomical kit - telescopes etc - I can recommend it. I went along to day and managed to keep the wallet in my pocket. But it was very interesting.
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#2913 |
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Join Date: Jun 2006
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NASA Apollo archive put online. See Thousands of NASA Aplollo photos uploaded online
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#2914 |
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Join Date: Jun 2012
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Quote:
Beat me to it.
![]() http://phenomena.nationalgeographic....h-a-dark-past/ http://www.bbc.co.uk/news/science-environment-34420062 Why all those posters of the Solar System are utter bollocks. http://phenomena.nationalgeographic....rong-till-now/ Remember that this is just the major Planets - the distance involved are utterly insignificant compared to what is beyond Neptune - the Kuiper Belt, Scattered Disc and all the way to the Oort cloud - it boggles the mind. ![]() For example, I know that our nearest neighbouring galaxy is Andromeda at 2.5 million light years distance. But what if we were to make our own Milky Way down to the size of a marble. How far away would the Andromeda marble be from the Milky Way one?
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#2915 |
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Quote:
....what if we were to make our own Milky Way down to the size of a marble. How far away would the Andromeda marble be from the Milky Way one?
![]() Andromeda galaxy would be about a foot away from us. M33 (the Triangulum galaxy) would be a smaller marble... maybe 13-14 inches away from us, and about 3½ - 4 inches from Andromeda. |
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#2916 |
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Join Date: Feb 2014
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Quote:
Well if our galaxy (approx 100,000 lt.yrs. diameter) was the size of a marble (about half an inch diameter).....
Andromeda galaxy would be about a foot away from us. M33 (the Triangulum galaxy) would be a smaller marble... maybe 13-14 inches away from us, and about 3½ - 4 inches from Andromeda. I am sure someone, somewhere will have calculated something similar at one time or another. |
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#2917 |
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Quote:
Well if our galaxy (approx 100,000 lt.yrs. diameter) was the size of a marble (about half an inch diameter).....
Andromeda galaxy would be about a foot away from us. M33 (the Triangulum galaxy) would be a smaller marble... maybe 13-14 inches away from us, and about 3½ - 4 inches from Andromeda. Quote:
A more interesting question would be if the earth was the size of a marble then how big would the Milky Way be?
I am sure someone, somewhere will have calculated something similar at one time or another. Clearly just about 12 inches or so! Not too impressive in the grand scale of things. Here's a good one regarding our Milky Way being just an inch across, then how far would the edge of the visible universe be in comparison. http://www.astronomycafe.net/qadir/q2139.html |
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#2918 |
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If our Sun was an inch in diameter then Proxima Centauri our nearest star at just over 4 light years distance would be 453 miles away to scale. You can imagine, or not, just how big that would make the whole Milky Way galaxy in that case.
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#2919 |
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I did once work out that on the basis of the Sun being a grain of sand 1mm in diameter, Neptune's orbit is a few metres across, the nearest star is another grain of sand 15 miles away, and the milky way then fits comfortably inside the orbit of the moon.
These things are interesting to work out, quite illuminating about the scale of the universe. |
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#2920 |
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Join Date: Mar 2013
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Quote:
Originally Posted by Keyser Soze
A more interesting question would be if the earth was the size of a marble then how big would the Milky Way be?
The sun is a 5 foot sphere, 170 yards away. (caveat - calculated in a hurry, may not be accurate) |
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#2921 |
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Join Date: Sep 2011
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Mysterious Ripples Found Racing Through Planet-Forming Disk
Interesting dynamics puzzle. It might be a while before we hear the solution though. |
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#2922 |
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Join Date: Oct 2011
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Quote:
I love these kind of tasks.
For example, I know that our nearest neighbouring galaxy is Andromeda at 2.5 million light years distance. But what if we were to make our own Milky Way down to the size of a marble. How far away would the Andromeda marble be from the Milky Way one? ![]() Another way of looking at this is that the Andromeda galaxy is approximately 100,000 light years across. So taking the distance of 2.5 million light years the apparent size of Andromeda galaxy in the sky is the same as viewing a meter ruler at 25 meters. In other words quite big. Bigger than the moon. It's just very faint. |
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#2923 |
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Quote:
....the apparent size of Andromeda galaxy in the sky is.....
.......Bigger than the moon. The Andromeda galaxy is somwhere in the region of 3 degrees across. It's dim, but still bright enough to be seen by naked eye from a rural site - and the best way to see it with your eyes (as opposed to a photo) is to use large aperture binoculars with relatively low magnification. It's far too large to fit into the field of view of any telescope big enough to give a decent image. (A telescope at even a low magnification of, say, 30x, will typically have a field of view diameter of only about 1½ degrees or so) My own personal best VISUAL observations have been through 20x80 binoculars, with a 3.8º FOV - Under a good dark sky it almost fills the field. |
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#2924 |
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Join Date: Apr 2009
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Cassini about to get up close and personal to Enceladus
http://www.nasa.gov/press-release/ca...moon-enceladus |
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#2925 |
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Join Date: Jun 2006
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Interesting article about one of the only two remaining S-IC Saturn V first stages
Plan to move it and preserve it. |
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Clearly just about 12 inches or so! Not too impressive in the grand scale of things.