Big bang background cosmic microwave radiation?

Question

I've heard of the concept of astronomers detecting microwave radiation from the big bang. But I don't know how this could be. If everything was created in the big bang, which was an explosion from a single point, and nothing can travel faster than the speed of light, and the microwave radiation travels at the speed of light (which it must as it is electromagnetic radiation) then how could we get in front of it so as to receive it now, without us travelling faster than light to get there?

I expect the answer probably involves relativity, which I can't easily get my head round.

Answer 1

Well, let's see if I can confuse the issue a bit more. . .

First, let's look at what we find concering the events right after the big bang.

From "Stephen Hawkin's Universe"

It all begins with a dramatic Big Bang explosion producing nothing but searing hot energy at first. This energy somehow develops slight variations in its texture as it spreads outward and starts to cool. This allows for slightly hotter spots where, within the first second after the Big Bang, energy starts converting into particles and antiparticles; and slightly cooler spots which are destined to become the first voids in space. Most of the particles and antiparticles start to be drawn close enough together by gravity for what is known as the electromagnetic force to make them combine; and most of the antimatter is lost in annihilations, leaving only matter swirling in growing irregular clumps. Until three minutes after the Big Bang, it is still too hot for these subatomic particles to build anything together; but then some of them start to bind into what will become the nuclei of atoms. It takes 300,000 years for things to cool down enough for electrons to couple with these nuclei to form the first atoms. By then about 20 percent of the nuclei are the heavier type found in helium; the other 80 percent are used to create hydrogen. All the other known chemical elements will evolve much later on.

Now, from what we have here, for the first few seconds, there was nothing but extreme energy (heat), and a lot of it. the tempertures were so high that matter could not exist. It was not until later that the elements began to form from the heat.

In 1948, George Gamow and his student Ralph Alpher, argued that the afterglow of the intense heat which created these elements would not have completely disappeared, even after billions of years.

They said that the radiation form this heat shoud still exist, and since the big bang expanded in all direactions, it should be everywhere!

So, they, and a team from Princeton, began surching for it, but, in 1960, they got a call from Bell Labs. It seems that they were picking up microwave interfearece and they couldn't find out why, so they thought that the scientist at princeton might help.

It truned oout that the radiation that Bell labs had discover was the very radiation they were seeking.

An interesting, but true story.

Answer 2

The microwave background is not from the time of the big bang. The microwave background is from a time shortly after the big bang. There was a time when the universe was so dense and hot that electromagnetic waves could not penetrate very far before encountering something that would block the progress of the wave/photon. When the Universe had expanded sufficiently and sufficient numbers of particle anti-particle pairs had annihilated themselves the electromagnetic waves were mostly equivalent to a particular temperature. The waves were everywhere going in all directions. The Universe has continued to expand over the several Billion years since that time. The waves that are arriving now have had their wave length made longer as they traversed Billions of light years of the expanding universe from someplace that was a long way from where we currently are.

Answer 3

You're not thinking about it correctly. The universe didn't explode from the big bang - it expanded. Think about blowing up a balloon, but in this balloon, all the air that will ever be in it is already in it as it expands. The microwave radiation didn't just go away from the point - it's everywhere, all of space. It was the point, and it expanded with it.

Answer 4

No one can easily get their head around relativity! I usually tell my students "If it makes sense, you obviously weren't paying attention!"

A few things to make your head hurt even more:

The Big Bang happened at a single point, but since the entire universe (all matter, energy, and space) was inside that point before the Big Bang, that means that the Big Bang actually happened everywhere!

Shortly after the Big Bang was the inflationary period. During this time the Universe actually did expand faster than the speed of light. I don't know how, that's one (of many) of the things I haven't gotten my head around yet. But somehow it doesn't violate any laws of physics.

Answer 5

We're not seeing all stars from the point they were created.

The very fact that we're here shows the big bang got this far some time ago and we're now getting the background radiation.

Answer 6

1964 when the radiation from the Big Bang was discovered.
Try Cosmic microwave background radiation
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

Answer 7

There is nothing to keep the radiation from echoing all around. It seems the radiation will be totally absorbed eventually, but that may take longer than the universe has left to exist.

Answer 8

Test for echo

Answer 9

Youre misconception is the "BANG"
BANG= sound/noun/to be.
So,there was no bang.

Answer 10

well we can hardly pick the earth up & put it somewhere else, can we?
it'll get here when it gets here.
the Big Bang is a theory & like all others it remains 2 b proved.
ok?
just my opinion.

not really fussed whether u agree or not.
so u believe ur grand-daddies daddy's etc, woz an ape?
well that's just a theory 2.