0 Members and 1 Guest are viewing this topic.
They probably meant the edge of the visible universe. Since light travels at a finite speed, it can only have traveled a certain distance in the 14 billion years the universe has been around. The light which can reach us defines a giant sphere (radius = 14 billion parsecs) around the earth. If something is further away than that, its light won't have reached us yet. Since light-speed is the speed limit for everything in the universe, nothing from beyond this region will have reached us yet, and so we don't know what's beyond it. Most scientists tend to believe in the cosmological principle, which says that the universe is pretty much the same everywhere, at least on large scales. Therefore, it should be basically the same outside our visible universe as it is inside. There's a lot more details here: http://en.wikipedia.org/wiki/Observable_universe
Correct in principle; but aren't the maths a bit awry? 1pc = 3.26 light years. Therefore the edge of the visible universe is 14billion/3.26 parsecs, not 14 billion parsecs.
Socratus - I assume your 2.7K refers to the CMBR. Surely, that can't ever reach 0K as that would imply zero energy level and QM says that is impossible.
Quote from: DoctorBeaver on 04/10/2008 11:30:24Correct in principle; but aren't the maths a bit awry? 1pc = 3.26 light years. Therefore the edge of the visible universe is 14billion/3.26 parsecs, not 14 billion parsecs.The extra distance is due to the expansion of the universe. I didn't discuss that detail since it's a bit tricky to grasp. The light has been traveling at c, but the space between us and those distant stars has stretched. Your numbers are right if the universe is static.
46 billion light years (14 parsecs) away.
jpQuote46 billion light years (14 parsecs) away. ??1pc is only 3.26ly, actually. You mean 14 billion pc, I think.
We've a long way to go yet.
Quote from: sophiecentaur on 07/10/2008 09:30:50We've a long way to go yet.==================It is pity. Is our intellect really so poor ?==========================
Quote from: socratus on 07/10/2008 14:22:46Quote from: sophiecentaur on 07/10/2008 09:30:50We've a long way to go yet.==================It is pity. Is our intellect really so poor ?==========================Our knowledge is
You're doing it again - assuming space is infinite. It's not difficult to explain how stars and galaxies formed; but they did not form from "an infinite vacuum".Initially, the universe was too hot for matter to form. As the universe expanded, it cooled. It reached the point where elementary particles could appear. Those particles joined to become forms of hydrogen. Gravity pulled massive clumps of this hydrogen together in areas of anisotropy - wrinkles in spacetime that hadn't been totally equalised by inflation - and galaxies formed.Within the hydrogen clouds, stars started to form. At first, gravity-powered stars formed. As those stars condensed further, they reached the point where nuclear reactions could take place to become stars as we know them today.There; and not a single mention of infinity 
this is where im troubled,the multiverse idea, in my book the universe is everything, all the stars, all the galaxies, all the clusters and yes all the multiverses and all the branes as well. the word universe should encompase all of the above
The CMBR is most definitely subject to the speed of light. It is composed of photons so it must be.I'm not sure what you mean by "What we do have defining our universe is the speed of light.". Do you mean that the speed of light defines the size of the universe? If so, then that is not necessarily true. During the period of inflation the universe expanded much faster than the speed of light1. If, however, you mean our visible universe, then you are correct.1. There is a popular misconception about the speed of light. What is limited is the transfer of information. There is nothing to stop superluminal speeds so long as no information is involved.
Ah i see. He was talking about tangible signals, such as electromagentic and gravitational.Thanks
Quote from: Mr. Scientist on 31/12/2008 09:44:53Ah i see. He was talking about tangible signals, such as electromagentic and gravitational.Thanksright. well, i don't believe that. I think certain types of quantum information my travel at superluminal speeds, but i will keep my speculations out of this.Any kind of information.