# Outer space and related interests • Page 3

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• DrStrangelove 29 Nov 2013 02:33:32 11,315 posts
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 I once asked this a physicist, but he didn't seem to have an answer. Maybe you Playstation experts know more (I imagine vizzini does, as he seems to understand even the greatest mystery in history, the Cell). I'm always looking for possible different explanations for things observed, no matter how dumb, in this case for the expansion of the universe. Just for fun. There's no way to tell which position/speed/velocity is "zero", or "centre", because that probably doesn't even exist. Because the universe and everything is relative and stuff. There is no absolute centre/resting point, or we would never know because it wouldn't make a difference. I can't tell if "I'm resting" and the other one moves, or if the other ones is resting and I'm moving. We just move in relation to others, we all know that. But if we leave behind linear motion, what about angular motion? Is the universe spinning? That was just one of my dumb thoughts when I thought about why the universe might expand. Let's imagine we're in empty space. No stars, nothing. Just our spaceship. We cannot possibly tell if we're moving or not, because there's nothing we could move in relation to. But we can tell if we're spinning, because either we feel a centrifugal force or we don't. But wouldn't that mean there's an absolute "non-spinning" resting point? We couldn't even tell if it's centrifugal force or some other sort of force pulling us apart. Now, same about the universe. How can we tell if the universe is spinning or not? We don't know anything beyond, so how can we tell if we're spinning or not related to something bigger? How can we tell if there's a centrifugal force at work or some other force pulling everything apart? Not trying to explain the actual expansion only by this, but this keeps confusing me. Couldn't find a solution so far, maybe you indie gamers know more?
• BeardedGamerUK 29 Nov 2013 08:01:29 2,148 posts
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 Poor Ison, the asteroid that tried
• grey_matters 29 Nov 2013 08:39:04 4,331 posts
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 DrStrangelove wrote: I once asked this a physicist, but he didn't seem to have an answer. Maybe you Playstation experts know more (I imagine vizzini does, as he seems to understand even the greatest mystery in history, the Cell). I'm always looking for possible different explanations for things observed, no matter how dumb, in this case for the expansion of the universe. Just for fun. There's no way to tell which position/speed/velocity is "zero", or "centre", because that probably doesn't even exist. Because the universe and everything is relative and stuff. There is no absolute centre/resting point, or we would never know because it wouldn't make a difference. I can't tell if "I'm resting" and the other one moves, or if the other ones is resting and I'm moving. We just move in relation to others, we all know that. But if we leave behind linear motion, what about angular motion? Is the universe spinning? That was just one of my dumb thoughts when I thought about why the universe might expand. Let's imagine we're in empty space. No stars, nothing. Just our spaceship. We cannot possibly tell if we're moving or not, because there's nothing we could move in relation to. But we can tell if we're spinning, because either we feel a centrifugal force or we don't. But wouldn't that mean there's an absolute "non-spinning" resting point? We couldn't even tell if it's centrifugal force or some other sort of force pulling us apart. Now, same about the universe. How can we tell if the universe is spinning or not? We don't know anything beyond, so how can we tell if we're spinning or not related to something bigger? How can we tell if there's a centrifugal force at work or some other force pulling everything apart? Not trying to explain the actual expansion only by this, but this keeps confusing me. Couldn't find a solution so far, maybe you indie gamers know more? Angular velocity means that the linear velocity is constantly changing. As far as special relativity is concerned, you cannot distinguish between two reference frames moving at constant velocity so I think that it doesn't apply in the same way. However, if you are experiencing a centrifugal force (from spinning) it should be indistinguishable from experiencing a constant force in a particular direction (like from gravity, say) so you still don't have a zero-point. Edited by grey_matters at 08:39:43 29-11-2013
• Deleted user 29 November 2013 17:45:06
 ALIVE!
• localnotail 29 Nov 2013 20:46:11 23,072 posts
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 \o/ Or rather / o \ slingshot FTW!
• Dirtbox 29 Nov 2013 21:00:48 89,409 posts
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 Post deleted
• DaM 29 Nov 2013 21:11:05 16,868 posts
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 Bugger, looks like I'm going to have to get up at daft o'clock next week, in the freezing cold.
• DrStrangelove 30 Nov 2013 10:06:36 11,315 posts
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 @grey_matters Yes, but I mean, consider totally empty space. Is there a "background" in relation to which an astronaut could be spinning? As far as I understand it, no. But the astronaut can feel either "normal" or feel his limbs being "pulled" away from him. So there should be a difference between spinning and not spinning even without a frame of reference. If I understand it right, it would be indistinguishable from some sort of force that pushes his mass apart (the farther away, the stronger), and that was my question about the universe. Whatever general force we try to think of to explain the increasing expansion of the universe, could we tell a difference to it just spinning? Maybe this all goes just a bit over my head, yet it doesn't get out of it either.
• FogHeart 3 Dec 2013 02:00:41 1,245 posts
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 @DrStrangelove You may be interested to know that the possibility of a rotating universe was explored by the uber-mathematician Kurt Godel. He found that using Einstein's laws in such a universe implied that time travel was not just possible but inevitable, all the time, and as a result causality breaks down. Since causality holds in our universe, it is agred to be expanding and not rotating.
• Deleted user 4 December 2013 14:58:07
• FartPipe 7 Dec 2013 09:39:04 5,307 posts
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• phAge 7 Dec 2013 10:04:16 25,239 posts
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 @OptimusPube Heh. I get an ad from "Recall Document Handling" on that page.
• FartPipe 7 Dec 2013 10:07:20 5,307 posts
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 Strange, handles fine for me.
• phAge 7 Dec 2013 12:28:13 25,239 posts
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 @OptimusPube Oh - the page works fine, and the story is cool, it's just Mars, Recall... Y'know. /may be assuming too much
• FartPipe 7 Dec 2013 12:34:06 5,307 posts
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 Oh fuck straight over my head, I've seen both films as well, the Arnie one and the new shit one.
• Fake_Blood 7 Dec 2013 16:04:55 7,915 posts
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 Thirty nine *days?* Hey man, I don't wanna rain on your parade, but we're not gonna last thirty nine *hours!*
• senso-ji 12 Dec 2013 23:08:09 8,129 posts
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• Deleted user 12 December 2013 23:46:15
 senso-ji wrote: The Universe is just a Hologram I just can't take that one in. I'm gonna have to read it again another day.
• oceanmotion 14 Dec 2013 21:09:40 17,269 posts
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• FartPipe 25 Jan 2014 05:31:29 5,307 posts
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• EMarkM 25 Jan 2014 06:40:24 4,399 posts
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 @OptimusPube Ooh, new and interesting
• Deleted user 1 February 2014 23:18:29
 Read Greg Bear's 'Heads'? You might enjoy this The Coldest Spot in the Known Universe
• RyanDS 2 Feb 2014 00:22:09 11,670 posts
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 My wife surprised me with a celestron 8 inch s-c goto scope today.  Been outside all night in poor skies but even through the haze I have had the best views of the orion nebula and jupiter I have ever seen.  Two top quality eyepieces and a barlow as well.  All for a grand.  The step up from a cheapo 130 eq is astounding.
• Deleted user 2 February 2014 00:39:31
 Ohhh I was tempted out by a clear sky, but it's just too damn windy.
• Deleted user 12 February 2014 22:48:58
 Jade rabbit hasconked out. Chinese build quality, eh.
• altitude2k 1 Mar 2014 07:43:43 5,238 posts
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 An amazing article about NASA's hypothetical Columbia rescue mission. Link Is long, but well worth a read.
• ZuluHero 1 Mar 2014 10:09:32 5,969 posts
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 It's called the Goldilocks zone... And "only" 100 light years away(!). Lol.
• Deleted user 10 March 2014 15:16:27
 The past few clear nights have got me thinking about getting the telescope out again. While I was browsing for interesting stuff to potentially look at, I came across this story: Hubble's First Frontier Field Finds Thousands of Unseen, Faraway Galaxies (bit old, but hey ho) which basically describes who space boffins are using the gravitational lensing of an entire galaxy to obtain images of much distant galaxies. Amazing. 'pooters+Einstein=mind-blowing.
• chopsen 10 Mar 2014 15:27:47 19,970 posts
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 The Hubble data is generally mind-blowing. You take a small patch of sky that just looks completely dark, and Hubble finds countless galaxies there. *Galaxies*. None of which we could otherwise detect, all which are made up of god knows how many stars. Yet to us, on Earth, even with the best scopes, it's just black empty sky.
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