The Big Bang

[MindExpansion]

I just farted and a very interesting question po ped to awareness.

What is the big Bang theory? What is the proof (no, smell those not count!)...What do you think:)?

[Elizabeth Isabelle]

What do you think:)?

I think you exaggerated when you said you were 17. So how was kindergarten today?
.

[MindExpansion]

lol

[Unidian]

The modern big bang theory is based on several observations in cosmology, including the homogeneity of the universe over large scales (as recently confirmed by the cosmic microwave background observations) and the inflationary properties of scalar fields. The data seems to indicate that approximately 13 billion years ago, a quantum fluctuation occurred in which a tiny space-time bubble was produced. Due to its favorable initial conditions, this spatiotemporal bubble underwent a brief exponential expansion which ended with the emergence of the four known fundamental forces of physics: gravity, electromagnetism and the strong and weak nuclear forces. These forces progressively acted upon the energy liberated by the broken symmetry of the expansion, creating particles of matter and gradually organizing them into the structures we observe today. Presently, the observable universe continues to expand at a reduced rate of acceleration. It is not yet known with certainty whether space beyond our Hubble volume (observable universe) is infinite or finite with a "no-boundary" condition, meaning that space is finite but one can never reach the end of it.

While some aspects remain unclear, the inflationary Big Bang model is well-accepted, and there are no seriously-considered alternatives, other than the various fringe and crackpot theories one encounters in any field. I include religious creationism in this category, for the record.

[Jamesh]

I would have deleted MindExpansion's account weeks ago.

[Unidian]

I was bored and felt like honing my science writing skills.

[Dan Rowden]

I would have deleted MindExpansion's account weeks ago.

I have been hoping against hope for a leap of sanity. Damn, you'd be a tough admin, Jimbo!

[Unidian]

I don't think you can flush people for being childish. Well, you can, but it's pretty draconian. Probably the only case in which I'd ban somebody like MindExpansion from a forum I administrate is if his antics were causing other people to get involved in a lot of mudslinging and drama, and thereby causing a major disruption. That doesn't seem to be happening here, so I think Dan & co are making the right call so far.

[MindExpansion]

NO!!! I like this place. It's fascinating. Hey I was half joking. Now, that guy...Hitler, he was no joke!

[MindExpansion]

Unidian wrote

The modern big bang theory is based on several observations in cosmology, including the homogeneity of the universe over large scales (as recently confirmed by the cosmic microwave background observations) and the inflationary properties of scalar fields. The data seems to indicate that approximately 13 billion years ago, a quantum fluctuation occurred in which a tiny space-time bubble was produced. Due to its favorable initial conditions, this spatiotemporal bubble underwent a brief exponential expansion which ended with the emergence of the four known fundamental forces of physics: gravity, electromagnetism and the strong and weak nuclear forces. These forces progressively acted upon the energy liberated by the broken symmetry of the expansion, creating particles of matter and gradually organizing them into the structures we observe today. Presently, the observable universe continues to expand at a reduced rate of acceleration. It is not yet known with certainty whether space beyond our Hubble volume (observable universe) is infinite or finite with a "no-boundary" condition, meaning that space is finite but one can never reach the end of it.

While some aspects remain unclear, the inflationary Big Bang model is well-accepted, and there are no seriously-considered alternatives, other than the various fringe and crackpot theories one encounters in any field. I include religious creationism in this category, for the record.

Would it be rediculous to imagine our universe as a balloon, and everything else is on the surface?

So, it all started from? What is a cosmic microwave background?

So, the universe is expanding, does that mean eventually life on Earth cease to exist -I'm refering to our sun and yes I know there's the whole gravitational field....

Opposite Big Bang- Why would that happen?

God may have/be playing a role.

I'll write more later, gotta run and expand my mind!

[DHodges]

While some aspects remain unclear, the inflationary Big Bang model is well-accepted, and there are no seriously-considered alternatives, other than the various fringe and crackpot theories one encounters in any field.

In The Trouble with Physics, Less Smolin mentions an alternative hypothesis to inflation, where the speed of light is much higher in the early universe, dropping down to a constant when the density of the universe drops down to a certain point.

I suppose this is a "fringe" idea at the moment. The idea of the speed of light changing is kind of radical, and may be hard to test experimentally because of the energies involved. The visible effect would be the same as inflation, however.

[MindExpansion]

The universe is expanding, right? Is the distance between the sun and earth expanding?

[Unidian]

Would it be rediculous to imagine our universe as a balloon, and everything else is on the surface?

No, it's a pretty good analogy.

So, it all started from?

A quantum fluctuation, most likely. They happen all the time. Due to the way quantum mechanics works, "virtual particles" pop into existence out of "nothing." Most of them only last a tiny fraction of a second before being annihilated and going back to nothing, but physicists think it's possible for some to inflate into new universes, under the right conditions.

I personally kinda wonder if they all might do that, and their apparent annihilation in our universe is a result of them becoming independent space-time domains (new universes). But that's just my wild idea. I don't know if it has any support.

What is a cosmic microwave background?

The leftover heat from the Big Bang. It exists everywhere in space.

So, the universe is expanding, does that mean eventually life on Earth cease to exist -I'm refering to our sun and yes I know there's the whole gravitational field....

Yeah. Hopefully life will no longer be dependent on Earth by then, or it's toast (literally). The sun will undergo massive exapnsion as it runs out of energy, destroying the planet. Much later, all stars will run out of energy, and the universe will become extrememly cold and dark.

Alternatively, gravity might suck everything back together in a "big crunch," but that theory is losing favor.

[MindExpansion]

A quantum fluctuation, most likely. They happen all the time. Due to the way quantum mechanics works, "virtual particles" pop into existence out of "nothing." Most of them only last a tiny fraction of a second before being annihilated and going back to nothing, but physicists think it's possible for some to inflate into new universes, under the right conditions.

What are 'virtual particles?

How does something just 'pop' into existence, isn't there supposed to be a cause/effect?

Annihilated, by what? Does it have something to do with anti- matter?

'What is' gravity? I can only define it by its effect, what's the cause?

Hypothetical senerio: Lets say someone has dug a straight tunnel through earth, what would happen if they jumped in (ignore friction.)?

So, we are pulled towards the centre of earth, what would happen if we reached the centre, would we be crushed?

[MindExpansion]

LOL -The Milky Way...LOL