tbourner Posted March 30, 2011 Share Posted March 30, 2011 The thing about expanding spacetime though, that freaks me a bit, is that why would it affect the physical universe? Can someone run that past me please. My analogy is like, if you got a 10" monitor that was 1000*1000 pixels in size, to those pixels their universe is 1000 by 1000 of the smallest units of measurement they can physically measure. If you then stretched it to 20" square instead, it'd still be 1000*1000 pixels wide and the pixels themselves would, having no frame of reference other than the 1000*1000 grid, see no change whatsoever So how come stretching spacetime is making stuff move further away? I'm not saying it isn't because of redshift and so forth, I just can't get a grip on it. I was thinking that, it seems more like the universe we know is expanding inside something else, and maybe the something else has some grip on space and/or time and it's linked to the medium of our universe as well as whatever medium this outside space is made of. I know it's still thinking in simple terms, but the whole idea that every single molecule of everything (and nothing) started off as a miniscule dot before the big bang, makes you wonder where it was - just floating about in a big white room somewhere? Quote Link to comment Share on other sites More sharing options...
TLicense Posted March 30, 2011 Share Posted March 30, 2011 someone who gets it This shows up the fallacy of the "well if I'm in a car doing the speed of light and turn my headlights on, what happens" argument. 1) a car physically can't do the speed of light due to mass reaching infinity and the energy input required also reaching infinity, and 2) length falls towards zero as well, so good luck finding the button on the dash. The thing about expanding spacetime though, that freaks me a bit, is that why would it affect the physical universe? Can someone run that past me please. My analogy is like, if you got a 10" monitor that was 1000*1000 pixels in size, to those pixels their universe is 1000 by 1000 of the smallest units of measurement they can physically measure. If you then stretched it to 20" square instead, it'd still be 1000*1000 pixels wide and the pixels themselves would, having no frame of reference other than the 1000*1000 grid, see no change whatsoever So how come stretching spacetime is making stuff move further away? I'm not saying it isn't because of redshift and so forth, I just can't get a grip on it. I think the reason the pixels would never know is because they would be all travelling at the same speed. So if I glanced at your monitor as I rushed past at very close to the speed of light it would seem a lot smaller than 10". For the pixels all together at their relatively slow speed, they all seem to be the same size. This shrinking of the universe would help massively with interstellar travel, if it ever happens. If you're travelling to somewhere 100 light years away, you accelerate up to close to the speed of light and the universe shrinks around you, so instead of taking 100 years to get there, it will only take say 70. For the on-lookers, even those who you were travelling towards, it would have taken you 100 years, but for you only 70 would have passed. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 30, 2011 Share Posted March 30, 2011 I was thinking that, it seems more like the universe we know is expanding inside something else, and maybe the something else has some grip on space and/or time and it's linked to the medium of our universe as well as whatever medium this outside space is made of. I know it's still thinking in simple terms, but the whole idea that every single molecule of everything (and nothing) started off as a miniscule dot before the big bang, makes you wonder where it was - just floating about in a big white room somewhere? I don't buy the whole universe-in-a-box thing I think it's a question rendered as irrelevant as the "car headlights" one, because you're asking for details on something outside of our entire frame of reference. It's a self defeating question - if you can measure what's "outside" our universe using stuff that exists inside our universe, then the outside isn't separate from our universe - it's just a difficult to reach bit of it. You can never say "This is wholly separate from our existence" and prove it because proving it means our existence has a connection to it, ergo, not wholly separate I think the reason the pixels would never know is because they would be all travelling at the same speed. So if I glanced at your monitor as I rushed past at very close to the speed of light it would seem a lot smaller than 10". For the pixels all together at their relatively slow speed, they all seem to be the same size. But you're outside the monitor and therefore irrelevant to the land of the pixelites To the pixels, their 1000*1000 grid is all they have, their entire frame of reference. They could be to us as wide as a singularity and then expand to a billion miles across each, but to them, it still only takes 1000 discrete steps to cross from one side to the other. So how can they possibly know their uiverse is expanding. Thats a simplified version of our universe - I don't understand it. Unless the spacetime grid on the Planck scale is getting bigger i.e. increasing in the number of "pixels" rather than the pixels themselves expanding. I confuse myself This shrinking of the universe would help massively with interstellar travel, if it ever happens. If you're travelling to somewhere 100 light years away, you accelerate up to close to the speed of light and the universe shrinks around you, so instead of taking 100 years to get there, it will only take say 70. For the on-lookers, even those who you were travelling towards, it would have taken you 100 years, but for you only 70 would have passed. You might be getting confused with relativity - that stuff happens now, time slows down for you the faster you go compared to someone at a stationary position relative to you. Some scientists proved it with a pair of synchronised atomic clocks - they wanged one around the world in a jet for a while while the other sat still on the ground, and the one that sat still measured a (mind bogglingly tiny but well within atomic clock accuracy) older time than the one flown around. -Ian Quote Link to comment Share on other sites More sharing options...
TLicense Posted March 30, 2011 Share Posted March 30, 2011 But you're outside the monitor and therefore irrelevant to the land of the pixelites To the pixels, their 1000*1000 grid is all they have, their entire frame of reference. They could be to us as wide as a singularity and then expand to a billion miles across each, but to them, it still only takes 1000 discrete steps to cross from one side to the other. So how can they possibly know their uiverse is expanding. Thats a simplified version of our universe - I don't understand it. Unless the spacetime grid on the Planck scale is getting bigger i.e. increasing in the number of "pixels" rather than the pixels themselves expanding. I confuse myself You might be getting confused with relativity - that stuff happens now, time slows down for you the faster you go compared to someone at a stationary position relative to you. Some scientists proved it with a pair of synchronised atomic clocks - they wanged one around the world in a jet for a while while the other sat still on the ground, and the one that sat still measured a (mind bogglingly tiny but well within atomic clock accuracy) older time than the one flown around. -Ian It's different sides of the same coin. If you take off with your atomic clock and flew for 5000 miles at 500 mph, according to your clock on the ground, it could sit back and watch the plane complete the distance in 10 hours. According to the clock on the plane it would have travelled for less time, say 9 hours, yet it's still covered the same distance of 5000 miles. The only way this is possible is if the distance has shrunk. This has been proven... An experiment was conducted using an Alternating Gradient Synchrotron in New York where muon particles (which have a lifetime measured in microseconds before they turn into electrons and neutrinos) were accelerated up to very close to the speed of light. The synchrotron had a diameter of 14m which meant at the speed they were travelling at they should have completed 15 laps and then turned into electrons, but they actually lived for something more like 400 laps. For the muon's the time they'd been around for is the same (not for the stationary observer though) but they'd covered a further distance. For the muon's Space must have shrunk. http://en.wikipedia.org/wiki/Length_contraction A book I have (by everyones favorite, Brian Cox) uses a nice analogy that if a 4 metre long car traveled at 22% of the speed of light it could fit into a 3.9 metre garage. Not quite sure what would happen if you hand-braked it into there, whether you would get into the garage and then burst out of both the front and back as you came to a stop though. Quote Link to comment Share on other sites More sharing options...
jazz1 Posted March 30, 2011 Share Posted March 30, 2011 Most scientists know there has to be an intelligent force behind this planned creation, funny thing to me is we won't have the intelligence to ever find the truth behind the wonderful universe. My theory and faith is simple I believe in my signature:). Quote Link to comment Share on other sites More sharing options...
Thorin Posted March 31, 2011 Share Posted March 31, 2011 Most scientists know there has to be an intelligent force behind this planned creation, funny thing to me is we won't have the intelligence to ever find the truth behind the wonderful universe. My theory and faith is simple I believe in my signature:). I beg to differ Quote Link to comment Share on other sites More sharing options...
tbourner Posted March 31, 2011 Share Posted March 31, 2011 Most scientists know there has to be an intelligent force behind this planned creation, Some scientists believe that, but absolutely NO scientist would say they know for certain there's an intelligence at work - otherwise they're not a scientist. Quote Link to comment Share on other sites More sharing options...
TLicense Posted March 31, 2011 Share Posted March 31, 2011 I don't buy the whole universe-in-a-box thing I think it's a question rendered as irrelevant as the "car headlights" one, because you're asking for details on something outside of our entire frame of reference. It's a self defeating question - if you can measure what's "outside" our universe using stuff that exists inside our universe, then the outside isn't separate from our universe - it's just a difficult to reach bit of it. You can never say "This is wholly separate from our existence" and prove it because proving it means our existence has a connection to it, ergo, not wholly separate Just by pure coincidence I've just read something about CMB (Cosmic microwave background) which when mapped shows a "cold spot", where much lower radiation levels are recorded. Some theories suggest this may be a point in our universe that is merged with another universe. Other theories suggest it may just be a statistical feature. http://apod.nasa.gov/apod/ap110321.html As Harry Hill would say, there's only one way to find out....... Quote Link to comment Share on other sites More sharing options...
tbourner Posted March 31, 2011 Share Posted March 31, 2011 Just by pure coincidence I've just read something about CMB (Cosmic microwave background) which when mapped shows a "cold spot", where much lower radiation levels are recorded. Some theories suggest this may be a point in our universe that is merged with another universe. Other theories suggest it may just be a statistical feature. I thought it was because the (very) early universe was still following quantum mechanics principles, so by definition there was randomness involved, and then it exploded and the random elements were propogated throughout the universe. Don't know why there would be such confusion over a random cold spot. Quote Link to comment Share on other sites More sharing options...
edinlexusV8 Posted April 4, 2011 Author Share Posted April 4, 2011 Scroll to the bottom ... Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 5, 2011 Share Posted April 5, 2011 It's different sides of the same coin. *stuff that made sense* Aha thank you for that, I shall read the article It kinda helps explain why length approaches zero as you approach lightspeed then, I guess? Distance shrinks so much you go two dimensional. Speaking of two dimensional, I see the religious squad have turned up to ruin things Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 5, 2011 Share Posted April 5, 2011 I thought it was because the (very) early universe was still following quantum mechanics principles, so by definition there was randomness involved, and then it exploded and the random elements were propogated throughout the universe. Don't know why there would be such confusion over a random cold spot. Last I heard about matter clumping, people were still as it should have been a "smooth" universe. Maybe it's the epicenter, wouldn't that be cool Quote Link to comment Share on other sites More sharing options...
CJ Posted April 5, 2011 Share Posted April 5, 2011 ...Speaking of two dimensional, I see the religious squad have turned up to ruin things Don't worry, it's only Jazz. He makes the "where's my turbo's" chap look like Einstein's protege. Quote Link to comment Share on other sites More sharing options...
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