Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: neilep on 29/04/2008 21:13:27
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Dear Peeps Of inspiring Wonder and Awe.
See my Universe ?
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Nice eh ?
Being delivered next Tuesday...though, I've been warned to make my display cabinet larger because it grows at a fast rate.
Y'see, I do find it hard to get to grips that there is no center to the Universe...and yet we are supposed to believe that it all began from an infinitesimally small bit of Uni stuff that then decided to eat three shredded wheat and grow bigger.
Surely, the place where the small Uni thing began is still there yes ?.....
Put it like this....when the Universe was the size of this ping pong ball
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.....then like this ping pong ball I could cut it in half and there would be a center !.........so....even though the ping pong ball is expanding...the center of it is still there being all central and stuff !!
......isn't it ?
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i myself think there probably is a beggining end and centre of the universe as everything ends and everything starts like they say notihng lasts for ever
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i myself think there probably is a beggining end and centre of the universe as everything ends and everything starts like they say notihng lasts for ever
THANK EWE BENEP.
What a truly wonderful and profound answer. Truly one of inspiration and wisdom.
Your dad is so lucky to have ewe as his son. [;)]
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lol thank you im lucky to have you as a dad tho you're a bit hmm i dunno just something well i better be off to bed night all
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Of course there's a centre to the universe. It's called Beaverland! [:D]
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Of course there's a centre to the universe. It's called Beaverland! [:D]
DOH !! (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fbestsmileys.com%2Fdoh%2F1.gif&hash=5735892d469a4533f4f2ec4dd35a0262)
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http://www.thenakedscientists.com/forum/index.php?topic=14107.msg170095#msg170095
http://www.thenakedscientists.com/forum/index.php?topic=10298.msg127166#msg127166
http://www.thenakedscientists.com/forum/index.php?topic=4813.msg38895#msg38895
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Nailep you are in fact living on a planet in a galaxy stuck in the thickness of your ping pong ball and can only look through the material, so when you look out you can only see the back of your head as the light rays run round the skin of the ball and can never see the centre. [;D]
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Y'see, I do find it hard to get to grips that there is no center to the Universe...and yet we are supposed to believe that it all began from an infinitesimally small bit of Uni stuff that then decided to eat three shredded wheat and grow bigger.
Surely, the place where the small Uni thing began is still there yes ?.....
I think the idea that the universe is getting bigger is where the confusion exists.
There is no reason to believe that the universe is getting bigger, smaller, or remaining the same size. There is no external reference point by which we can measure the size of the universe.
What we can say is that using the scale of things around us as a reference point, the distance between things is getting further apart. There is no way of saying whether in reality the distance is changing, or we are getting smaller - in practical terms, they are indistinguishable.
In the beginning, if we had existed then, we would have been so big that the whole universe would have appeared to have been smaller than a single atom of ourselves - so in relation to us, the universe was infinitesimally small. As time progressed, so we would have appeared to grow smaller and smaller, and so the universe would have appeared to grow bigger and bigger. Now the universe is so small that we are almost an infinitesimal part of the universe, and we are still shrinking in relation to the universe.
Since we are getting smaller (or at least, we cannot distinguish between a situation where we get smaller or the universe gets bigger), there is no need for there be a centre of the universe, just a centre of us.
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If there isn't an edge, how can there be a middle - if middle means equal distances from the edge?
Surely, anywhere will behave as if it is the middle.
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Aha - the 'middle' word:)
Does 'center' mean the middle or does it mean the origin? The center or middle of something is a proportional quality whereas an origin is not.
The time dimension of our four-dimensional universe can't be said to have a middle because, as sophiecentaur points out, you can't have a middle without an edge, and while time appears to have an origin it doesn't appear to have a terminating edge.
One way to look at this is to imagine a line n units long. If that line is fixed in length the middle would be at n/2 but if that line is unbounded in length the middle is undefinable, even if the origin is known. If the line is constantly increasing in length, the location of the middle has to constantly change at the same time.
So if we consider the time-line of the universe, we can say that it appears to have an origin, but not a fixed middle and we can also say that the middle and the origin were never at the same place, except for the very point of origin when everything was zero. In any case, the 'middle' of time doesn't really have any have any special significance and doesn't tell us anything.
Now if we use an expanding 2d square to represent the expanding universe we would normally assume that the origin of the square is at it's center, and the problem is that we then carry that idea over to the universe. With the universe though, it is as if the origin is at one corner of the square and not it's geometrical center. Now instead of using a square, we should really be using a circle but if we do, where do we put the origin? With a square, there's a clear difference between the point on a corner and a point along one of the straight edges but with a circle there isn't - all points around it's circumference are equivilent.
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If there are two atoms, next to each other, at the start of this expansion. One is at your 'origin', the other is just beside it. As the Universe expands, the one at the 'origin' stays still(?) and the other moves away. What is the actual distribution of the particles at the start of this? Are they all at a point (discontinuity) or do we already have an edge, even at the beginning?
I think you are being hampered by an implied Cartesian idea of space which you are using in your original model of the point where / in which it all starts.
Frankly, I think is much easier not to need an origin or and edge or, even a beginning, as such. 'Before' time started or 'outside' space are not parts of the set which is space time so they really have no relevance if all you discuss is space time.
Yes, it can all be 'part' of something else but that doesn't have to involve middles or terminators. It's interesting that people don't look for a ' half the life of the Universe' but they have to look for a middle, spacially. I think that says a lot about the basic way humans think.
Throw away all your baggage and go with the flow. It's essential if you are to make real progress in understanding (Grasshopper).
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<Robert_de_Niro>You talking to me?</Robert_de_Niro> :)
Atom twins walked into a Big-Bang and one said to the other "Hey, why are you leaving? We just got here" and the other one said...
Ah well ping-pong ball eyes (for those who don't remember the old Kung-Fu TV series, this is not an insult:), it certainly would make things easier if there was no origin, edge or beginning for there would then be nothing needing to be reconciled. As it is though, the universe does appear to have a clear origin along the time-line insofar as we can extrapolate backwards in time to the initial Planck epoch, when time effectively started. Time may have existed before then Jim, but not as we know it.
The phrases "Before time started" and "outside space" must be the ultimate oxymorons.
Afaik, no particles were created until after inflation, when space and time were already well above zero in size and expansion was already under way.
You could say that the two atoms, while being in different spatial places, are at the same temporal point, the temporal origin, at the BB, but after a subsequent period of time, neither are there, even though that's where they both started. With the spatial origin, everything moves away from it in space just as it does in time, so one atom wouldn't be left at the origin.
It's actually easier to work with a zero-sized point origin than an infinitely small one. With a zero-sized point origin everything starts from exactly the same place, so there is no question of one atom being 'beside' another. In an infinitely small origin there's scope for atoms being spatially beside each other because none of the dimensions are zero, but if everything is infinitely small, you could also say that everything becomes indeterminate, so while the atoms may be beside each other, they're also the same size and occupying the same space, which is also the totality of the origin and amounts to everything being in the same place again. While it's possible to do the maths with infinities and get consistant answers, I don't think that applying it to real entities, below the planck limits for time and size, really tells you anything.
I don't think that using Cartesian models to try to illustrate some aspects of space-time is such a bad idea - it's a more natural way for people to think. How many people find it easy to conceptualise a four-dimensional cone and it's parabola(s)?
Perhaps it's not so much down to the way that people think but how much people can think.