What evidence exist to support the big bang?

Answer 1

The cosmic microwave background and the expansion of the Universe, to begin with. And considering how little evidence there is AGAINST it, that's quite enough.

Answer 2

Others have said it, the cosmic microwave background. But some details are useful.

When the Big Bang theory was first proposed, few scientists believed in it. It was the crazy theory, the sensible theory was steady state.

Two things changed that.

First a scientist in the 1930s said the afterglow of the Big Bang should be observable, as microwave radiation, with a temperature of 3 degrees K, permeating the whole universe. In the 1950s someone found that radiation. That convinced most scientists that the Big Bang was correct. But some steady state guys came up with explanations for the microwaves. Not great explanations, but plausible.

Then another scientist pointed out the microwave radiation should have very tiny ripples in it, with a certain shape. These were the marks of minor irregularities in the Big Bang that would lead to the formation of stars and galaxies. We launched a satellite, looked for them (very hard, they're tiny) and found them, with the predicted size and shape. Those ripples convinced almost all scientists that the Big Bang theory was correct. Nobody has proposed another good explanation for the ripples.

We've since launched another satellite to look at the ripples even more closely. The results are consistent with the Big Bang theory.

Most scientists now consider the Big Bang theory as one of the better proven theories. Like 99+% likely to be true.

Good book about this:

http://www.amazon.com/afterglow-creation...

Note that nothing in the Big Bang theory (or for that matter, in all of science) denies the possibility that the bang itself was created by a higher power. It only covers what happened immediately after the bang.

Answer 3

First, the expansion of the universe was first predicted from Einstein's equations. Since he didn't like that conclusion, he added another term to his euqations that allowed for a static universe. He later described it as the biggest blunder of his life.

Edwin Hubble made measurements of the red-shifts of galaxies and found that the amount of red-shift was related to how far away the galaxies are from us. This type of relationship was what was predicted from Einstein's equations. This was the first solid evidence of the big bang. The correspondence between distance and red-shift (which is related to velocity which galaxies are moving away from us) has been measured and confirms that expansion has been going on for billions of years.

Later, it was realized that the temperature of the universe would have been higher the further you go back into the past. This allowed us to model the types of nuclear reactions that would have occurred then. This allowed predictions of the abundances of various elements like ydrogen, helium, and lithium in the universe. Using spectroscopy, these predicted abundances have been verified.

Next, very early after the big bang, the temperature and density of matter and light was such that light would not have been able to travel through the matter (i.e. things were opaque to light). As the universe cooled down, it reached a point where the light was able to freely move. In this model, the nature of the 'glow' from this should be observable today and was predicted to have a very specific frequency distribution (black body). This has actually been observed and the frequency distribution predicted matches that predicted. This is the 'microwave background radiation'.

Next, the fluctuations in that background radiation help to distinguish between several scenrios of how the big bang actually played out. The one that matches the fluctuation evidence also solves several difficulties that a simple big bang scenario has (such as the horizon problem and the curvature problem).

From all this evidence and more, we feel like we have a very good handle on how the universe has expanded and reacted back to within a fraction of a second after the big bang.

It is important to realize that the big bang is *not* an explosion of matter in any usual sense. It is an expansion of space itself. Also, because of the way hot dense matter and light bend spacetime, it is possible that there is no way of extending the notion of time to 'before the big bang'. It may make no more sense to talk about 'before the big bang' than it does to talk about 'north of the north pole'.

Answer 4

The Big Bang theory is an effort to explain what happened at the very beginning of our universe. Discoveries in astronomy and physics have shown beyond a reasonable doubt that our universe did in fact have a beginning. Prior to that moment there was nothing; during and after that moment there was something: our universe. The big bang theory is an effort to explain what happened during and after that moment.

According to the standard theory, our universe sprang into existence as "singularity" around 13.7 billion years ago. What is a "singularity" and where does it come from? Well, to be honest, we don't know for sure. Singularities are zones which defy our current understanding of physics. They are thought to exist at the core of "black holes." Black holes are areas of intense gravitational pressure. The pressure is thought to be so intense that finite matter is actually squished into infinite density (a mathematical concept which truly boggles the mind). These zones of infinite density are called "singularities." Our universe is thought to have begun as an infinitesimally small, infinitely hot, infinitely dense, something - a singularity. Where did it come from? We don't know. Why did it appear? We don't know.

After its initial appearance, it apparently inflated (the "Big Bang"), expanded and cooled, going from very, very small and very, very hot, to the size and temperature of our current universe. It continues to expand and cool to this day and we are inside of it: incredible creatures living on a unique planet, circling a beautiful star clustered together with several hundred billion other stars in a galaxy soaring through the cosmos, all of which is inside of an expanding universe that began as an infinitesimal singularity which appeared out of nowhere for reasons unknown. This is the Big Bang theory.

Answer 5

(1) the observed expansion of the universe;

(2) the cosmic-microwave-background-radiation which is the residual temperature left over from the Big Bang

Answer 6

Significantly more than evidence to support the presence of a divine being creating the universe.

Answer 7

The cosmic microwave background and red-shift in different galaxies, to name a few.

Answer 8

The universe is expanding, cosmic background radiation, deuterium/hydrogen ratios...there really is no evidence against the theory.

oh yeah, and, "Planets, duh"??

Answer 9

Planets duh ,