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Subject:
Expansion
Category: Science > Astronomy Asked by: charles_smith-ga List Price: $10.00 |
Posted:
24 May 2004 21:15 PDT
Expires: 23 Jun 2004 21:15 PDT Question ID: 351489 |
To begin with, know that I enjoy Cosmology, but Havn't a clue about what I read means beyond the laymen explanations. Here goes anyway. In all directions, expansion per Hubles Constant. If two objects exist, one 100 light years to the left, and one same distance to the right, they are both moving away at the same rate. Now add two more. So a total of five objects, us in the middle. The object to the immediate left sees us to the right, and another to the left 100 light years to the left. Both of them expanding at the same rate away. So no matter where you are, objects appear to be moving away from you. (Not including local objects) So, can I conclude that no matter where you are, you are stationary to everything else, and that no matter where you are, you are the center of the univers? Since I know the answer (although It makes no sense to me) I ask the bigger question: Isn't god spreading himself kind of thin? No, just kidding. What I want to know is this. In any direction you look, are you not bound to find objects moving a relativistic velocities? What effect does this speed have on such massive objects with respect to their gravity, as in high speed motion increasing or appearing to increase mass. |
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There is no answer at this time. |
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Subject:
Re: Expansion
From: rnt20-ga on 27 May 2004 02:07 PDT |
Yes you are correct -- it is allowable in Einstein's laws for different parts of "space-time" to be moving with velocities which differ by more than the speed of light. Objects within a given "patch" of space-time cannot travel faster than light. It is interesting to think about what happens when you try too look at an object which is very far away in the Universe. The further away an object is, the longer it takes for the light to reach you. This means that when you look at an object a hundred light years away, what you see is how the object looked a hundred years ago. Interestingly, if you do the math you find that distance away in the Universe where space-time is moving away from us at exactly the speed of light, is exactly the distance where light takes the full lifetime of the Universe to reach us. If you try to look this far with modern (CMB) telescopes you find that there aren't any stars, there's just hot gas which is opaque. This hot gas is the explosion from the Big Bang -- in other words CMB telescopes such as WMAP, COBE and VSA have taken pictures of the "fireball" from the Big Bang (redshifted to longer wavelengths). See the website: http://www.mrao.cam.ac.uk/telescopes/vsa/images_extended.html for some example pictures of small parts of the fireball from the Big Bang. "Fireball" is a slightly misleading term as the "fire" was everywhere in the Universe at the time. To see this, look at the all sky "map" of the fireball at: http://map.gsfc.nasa.gov/m_or.html This map is plotted just like a "World Map", but instead of showing the countries on Earth, it show how the light from the Big Bang is distributed over the whole "sky" all around the Earth. |
Subject:
Re: Expansion
From: rnt20-ga on 28 May 2004 02:04 PDT |
One other point I should have mentioned -- the mass associated with the kinetic energy of an object depends on the frame of reference. A fast moving body does not feel any heavier -- it only appears heavier to observers moving at a different velocity. It's all quite counter-intuitive at first sight, but comes out of a small number of very simple equations which describe a very simple way of looking at the Universe. It is also quite well tested experimentally. |
Subject:
Re: Expansion
From: rnt20-ga on 28 May 2004 04:06 PDT |
This news report appeared today, and is quite relevant to you questions on the expansion of the Universe: http://news.bbc.co.uk/2/hi/science/nature/3753115.stm |
Subject:
Re: Expansion
From: touf-ga on 06 Jun 2004 11:25 PDT |
We used to have a shirt for sale in our school of engineering student affairs office about why it's great to be an engineer. Among other reasons were "free cable" and what more and what not. The number one reason is that we're the center of the universe - we establish our own coordinate system. So yes, YOU are the center of the universe whenever you want to be. Heck, you can even say the earth is the center of the solar system and that everything rotates around it. You can say whatever you want - just back it up with your coordinate system, which YOU define. Sure, the equations get harder, but isn't it worth the ego trip? That's all... |
Subject:
Re: Expansion
From: digsalot-ga on 06 Jun 2004 20:34 PDT |
All of us associated with Google answers, researchers, non-researchers, editors and hangers on ARE the center of the universe and we can prove it by means of concentric circles. Cheers digs |
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