‘Oumuamua sandcastles Senior Member Posts: 424 Threads: 45 Joined: Jun 2016 11-20-2018, 11:00 AM I did a search for `Oumuamua; nobody has discussed it here?   I was wondering about something.  Astronomers were getting different estimates for its dimensions.  It seems to be long and thin, but 3km, 10km, or something else? So I was wondering if random impacts might have left it with a more unusual shape.   Pieces might break off, but gravity might pull them back together in (seemingly) random fashion. Is it too unlikely that `Oumuamua is shaped like:  A spoon, a fork, a tractor, a desk lamp...?  Not exactly like those (probably) but fairly close.  That might explain the inconsistent estimates on its size and proportions. On the other hand, I haven't actually studied to data leading to those results...oh, well. SeanR Senior Member Posts: 323 Threads: 30 Joined: Apr 2017 11-20-2018, 12:21 PM (This post was last modified: 11-20-2018, 12:23 PM by SeanR.) (11-20-2018, 11:00 AM)sandcastles Wrote: I did a search for `Oumuamua; nobody has discussed it here?   I was wondering about something.  Astronomers were getting different estimates for its dimensions.  It seems to be long and thin, but 3km, 10km, or something else? So I was wondering if random impacts might have left it with a more unusual shape.   Pieces might break off, but gravity might pull them back together in (seemingly) random fashion. Is it too unlikely that `Oumuamua is shaped like:  A spoon, a fork, a tractor, a desk lamp...?  Not exactly like those (probably) but fairly close.  That might explain the inconsistent estimates on its size and proportions. On the other hand, I haven't actually studied to data leading to those results...oh, well. If pieces broke off, and were attracted by gravity to recombine, the overall shape would tend toward spherical. The gravity at the middle of a rod, toward the axis of the rod, is stronger than the gravity toward the axis of any other part of the rod, excepting the ends. The gravity is also toward the center of the rod. If you were standing on a cylindrically shaped Earth, with a round barrel equator, and flat poles, you would find that gravity at the higher latitudes, on the barrel face, was uphill. Likewise, toward the lower latitudes on the pole plates. If the Earth were cylindrically shaped, with the cap for the cylinder starting at what is now the Polar Circles, anything in Canada would roll downhill toward Brazil, or downhill toward the North Pole. Anything in Venezuela, likewise, would roll downhill toward Brazil or the South Pole, depending on whether or not it was above the Antarctic Circle, or below it. sandcastles Senior Member Posts: 424 Threads: 45 Joined: Jun 2016 11-20-2018, 12:54 PM "If pieces broke off, and were attracted by gravity to recombine, the overall shape would tend toward spherical." And `Oumuamua is not at all spherical, and its gravity is far weaker than Earth's. The pieces being dragged toward the center might be keeping their non-spherical shapes. I'll agree a tractor is not a likely shape, but maybe a pincushion or a starfish. If it can be shaped like a cigar, like most images show, then maybe it can be shaped like a spoon. Or a fork. I'll admit, I haven't done the math on it. SeanR Senior Member Posts: 323 Threads: 30 Joined: Apr 2017 11-20-2018, 01:12 PM (11-20-2018, 12:54 PM)sandcastles Wrote: "If pieces broke off, and were attracted by gravity to recombine, the overall shape would tend toward spherical." And `Oumuamua is not at all spherical, and its gravity is far weaker than Earth's.  The pieces being dragged toward the center might be keeping their non-spherical shapes.  I'll agree a tractor is not a likely shape, but maybe a pincushion or a starfish.  If it can be shaped like a cigar, like most images show, then maybe it can be shaped like a spoon.  Or a fork. I'll admit, I haven't done the math on it. I know that object isn't spherical. I can only surmise that, if it's not artificial, it was part of something larger once. Possibly a rapidly cooled plume from a meteor strike into something molten? Maybe something molten that was being stretched out by tidal forces, as it disintegrated in the orbit of some large body, when the large body was ejected, leaving it an orphan and cooling faster than gravity could pull it back together? This is all the speculation of someone who knows he's a layman in this area. If any part broke off, it'd either orbit the thing around its center of mass, wherever that was, or it'd clump close to its center of mass. It would not fuse back alongside, away from the center of gravity, unless there was an outside force acting on it to make that happen. https://www.youtube.com/watch?v=BD-lAwZHCZU AmrlKJaneway Active Member Posts: 69 Threads: 16 Joined: Mar 2013 11-26-2018, 04:23 PM I had a thought, but it might be a bit far-fetched, and maybe impossible and pointless. I'm not the smartest. I remember recently NASA probing an asteroid to collect samples and look for evidence of life-building materials. I don't know what the results where, or even if we've had a chance to analyse the samples yet. But if they do show something, and then we do the same thing to Oumuamua, could we not compare the results to each other, and perhaps create a semi-accurate model of what life could look like if it evolved in the system of origin? Sorry if I'm way off the mark, I was just curious. P.S. I was also wondering, if this thing just travelled through interstellar space and arrived here safely, could we perhaps use it's shape as a blueprint for our first interstellar missions? stevebowers Administrator Posts: 9,981 Threads: 403 Joined: Apr 2013 11-26-2018, 06:57 PM (This post was last modified: 11-30-2018, 07:16 AM by stevebowers.) 'Oumuamua is travelling very slowly, so is not a very good model for an interstellar spacecraft. In fact it is travelling at more or less the same rate as the Local Standard of Rest - that is to say, it is travelling at roughly the same speed as all the other stars in the Orion Arm if they were averaged out. The main reason it appears to be moving with respect to the Solar System is that we are not moving at exactly the same speed as the LSR. AmrlKJaneway Active Member Posts: 69 Threads: 16 Joined: Mar 2013 11-29-2018, 01:09 PM (This post was last modified: 11-30-2018, 07:16 AM by stevebowers.) (11-26-2018, 06:57 PM)stevebowers Wrote: 'Oumuamua is travelling very slowly, so is not a very good model for an interstellar spacecraft. In fact it is travelling at more or less the same rate as the Local Standard of Rest that is to say, it is travelling at roughly the same speed as all the other stars in the Orion Arm if they were averaged out. The main reason it appears to be moving with respect to the Solar System is that we are not moving at exactly the same speed as the LSR. Fair enough. So our existing "interstellar" crafts like Pioneer and Voyager are already outpacing it. « Next Oldest | Next Newest »

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