The Scientific American issue of this month comes with an extensive article about the Big Bang http://www.sciam.com/article.cfm?chanID=sa006&colID=1&articleID=0009F0CA-C523-1213-852383414B7F0147 Charles Lineweaver is one of the top-star astronomers nowadays, so anything that he says must be true I want to highlight these excerpts: "This ubiquity of the big bang holds no matter how big the universe is or even whether it is finite or infinite in size. Cosmologists sometimes state that the universe used to be the size of a grapefruit, but what they mean is that the part of the universe we can now see--our observable universe--used to be the size of a grapefruit." That is the Universe didn't necessarily came all it from a simgle point; instead our observable Universe sprang from a point. But there's still a lot of Universe outside our observable Universe. One popular theory is that the Universe is infinite in extension!. If all the universe was concentrated in a point at Big Bang, now it couldn't be infinite "Notice that, according to Hubble's law, the universe does not expand at a single speed. Some galaxies recede from us at 1,000 kilometers per second, others (those twice as distant) at 2,000 km/s, and so on. In fact, Hubble's law predicts that galaxies beyond a certain distance, known as the Hubble distance, recede faster than the speed of light. For the measured value of the Hubble constant, this distance is about 14 billion light-years" That's true. Some people say: galaxies can't recede faster than light because nothing can go faster than light! But we must consider that these galaxies are receding faster than c because spacetime is expanding, not because they are moving through spacetime faster than c. So, the radial comoving distance to our Hubble sphere (the Hubble sphere is the set of all the points being at a distance equal to the Hubble distance) is 14 Gly like the article says. Anything behind our Hubble sphere is receding faster than light
Hum, Yes, our observable Universe sprang from a point, and there is a lot more beyond, but that doesn’t <b>exclude</b> the idea that it all sprang from a `singularity`. There are theories that imagined that our universe is a small part of a (now) large bubble, that is n turn, just part of a foamy sea of bubbles that were created, each one containing a `separate universe`…. As for Hubble's law... The misconception is that galaxies are `moving`….they`re not; It’s space that is expanding. In fact anything beyond red shift 1.5 is `receding` faster than light speed. So no laws broken there... Please Register or Log in to view the hidden image!
