I’m watching a program on the Science Channel, and they are speaking about a number of interesting topics regarding space/time/black holes, etc.
A couple of things that don’t make sense to me, though and I’m wondering if someone can help me get a better grasp of them. I realize that this topic can stretch the mind, but these two in particular I find hard to accept.
The singularity was supposedly a thing smaller than an atom. From this, the entire universe was created. How can this be, if everything in the universe was created from inside this singularity?
According to the program, the explosion of the Big Bang was a fraction of a second in length, and created the universe almost instantaneously. This means that what flew out of this singularity moved faster than the speed of light, which I thought was not possible. Is the speed of light only applicable now, has it slowed since the big bang, is it possible to travel faster than the speed of light, or is there another answer?
The short answer to this was that space itself was expanding, and not really the objects in that space. The classic example is of imagining all the matter on the surface of a balloon, and the matter moving away from each other as the balloon being inflated.
Actually, they used the ballon example, and that works quite well. The speed at which this man was describing the big bang, however is what I have a problem with. He said that it happened in an instant, less than a second, and that before a second had expired the universe was already multiple light years in size (I can’t remember ther number, but it wasn’t 1 or 2. It was say thousands. A number that, if true, blows the speed of light as we know it out of the water. So is it the speed of dark matter that drove the big bang, or something else?
I know an hour long show is not enough time to get into this too deeply, but these things make no sense to me.
To expand on the short answer given above, the speed of light limit only applies to movement through space - there is no such restriction on the expansion of space itself.
Firstly, we don’t know whether the big bang began from a singularity.
We can extrapolate pretty far back but it’s not possible to do the maths for the singularity state so there isn’t currently any way of supporting or falsifying the idea that there was a singularity.
The early universe was far more densely packed with matter than the current universe. There is no limit to how much mass you can pack into a given space.
Ah, so the speed of space expansion is the key here. No cosmic speed limit like light to hold it back. Is that the idea?
So what exactly is moving at the speed of space? Dark matter, space itself, or everything in it? And if it is indeed everything in it, then wouldn’t light itself be forced to travel at the speed of space, much faster than its own speed?
How can this be? is the theory that at this point in time, there are no such things as atoms, electrons, protons or neutrons? There is just energy which morphs into these things after something like the Bang occurs? If something has mass, doesn’t it have to have dimensions?
I’m not sure that question 2 has been answered very well yet, but I am grateful for the attempts. Sometimes, these questions can blow me away. On to the wiki article, and thanks for the answers so far!
Here’s the problem - rewind the universe and you wind up with an ever decreasing volume and an ever increasing energy. Once the energy density reaches a certain point we can only begin to hypothesize about what is going on. Potentially there was a singularity, perhaps a very small volume of space-time. Regardless the effective temperature was off the charts.
Once the universe begins to expand, it begins to cool. You wind up with free quarks and electrons forming out of the energy soup. The process is identical to what happens in these large colliders like the LHC. Energy “freezes” out into matter. Problem of course is that this matter if bloody energetic and zipping all over the place. As the expansion continues the matter slows down enough that quarks bind together and form protons and finally a proton manages to attract and hold an electron.
You’re touching on the fundamental nature of matter, which can be hard to fathom when you move away from the conditions of normal, every-day life.
For starters, your typical atom is mostly empty space. A nucleus (protons + neutrons) of extremely high density, surrounded by a vastly larger region of completely empty space, encircled by very small, very light electrons. Get rid of those electrons and all that empty space, pack a bunch of nucleons together, and you have something like a neutron star, with a density of about 4 quadrillion times that of water.
And if you think a neutron is solid, well, the particle physics guys aren’t so sure. Go down to an even smaller scale, and you’re into quarks and muons and gluons and other weird stuff. “Solid” doesn’t really mean much on these scales, and there’s no particular reason you can’t cram a whole bunch of matter into a small volume of space if you use enough force.
It’s not meaningful to speak of the “size” of the Big Bang singularity-- At best, you can only talk about times very shortly thereafter, or a limit of such times as t -> 0. If, as seems likely, the Universe is infinite, then it has always been infinite, at any nonzero time after the Beginning.
And the tiny fraction of a second you’re referring to is probably the era of cosmic inflation, during which the Universe was exponentially expanding on a very short timescale (doubling in size every 10[sup]-25[/sup] seconds or so). The current Universe is still exponentially expanding, but much slower, with a doubling time of billions of years. It’s not entirely clear what caused the end of the inflationary era, or if something similar could happen again (either turning off or amplifying the acceleration we have right now).
