Ask Gugel Anything About the Big Bang

[Gugel]

Ask away.

[Duke]

What are your credentials?

[Gugel]

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What are your credentials?

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I'm not claiming to know everything and please correct me if I'm mistaken anywhere. I took some high level astronomy/cosmology courses in college and read a bit cosmology in my spare time. I'll be able to answer most questions in layman's terms.

[Gugel]

Here's some food for thought.

4% of the Universe is observable to us. In other words, it's made up of ordinary matter/energy.
22% of the Universe is dark matter.
74% of the Universe is dark energy.

Also, to clear up a common misconception: the Big Bang did not start from a tiny point. Well, it did, but probably not the way your thinking about it. There is no special direction in the Universe. There is no central point from which the Big Bang began and expanded outwards. The Universe started EVERYWHERE at the same time. The Big Bang was just as much here as it was billions of light years away. The whole Universe was just condensed into a very small volume (infinitesimally small) so everything was infinitely close together. So, was it a point? Yes. But it doesn't make sense to think of it from outside or on the edge of the point.

[Phil153]

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But it doesn't make sense to think of it from outside or on the edge of the point.

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How useful is the big bang metaphor then? What does it mean?

[Gugel]

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But it doesn't make sense to think of it from outside or on the edge of the point.

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How useful is the big bang metaphor then? What does it mean?

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Perhaps a more useful way to visualize it would be stripping the current Universe of everything (matter, energy, dark energy, dark matter). Then imagine huge tears throughout the Universe (every single nook and cranny of it) spewing forth massive amounts of energy. It's rapidly expanding and cooling over time and eventually, it's cool enough for matter to form.

[wacki]

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What are your credentials?

[/ QUOTE ]

I'm not claiming to know everything and please correct me if I'm mistaken anywhere. I took some high level astronomy/cosmology courses in college and read a bit cosmology in my spare time. I'll be able to answer most questions in layman's terms.

[/ QUOTE ]

Please explain why a specific cosmic microwave background radiation was definitive proof that the big bang theory was correct. Just curious how Georges Lemaître could have predicted that.

[Gugel]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
What are your credentials?

[/ QUOTE ]

I'm not claiming to know everything and please correct me if I'm mistaken anywhere. I took some high level astronomy/cosmology courses in college and read a bit cosmology in my spare time. I'll be able to answer most questions in layman's terms.

[/ QUOTE ]

Please explain why a specific cosmic microwave background radiation was definitive proof that the big bang theory was correct. Just curious how Georges Lemaître could have predicted that.

[/ QUOTE ]

When we look at Cosmic Background Radiation, we are actually seeing a snapshot of the Universe relatively soon after the Big Bang took place (~400,000 years after). It was the moment the Universe had cooled enough so that it went from being opaque to becoming transparent. It was also the moment energy and matter became two separate things. Anyway, this Cosmic Background Radiation is really far out and receding from us fast so it's grossly distorted (redshifted) into the microwave part of the light spectrum. But if we account for the redshift, we can determine the wavelength of the light that originally left the CBR and from that, we can determine the temperature (~2800 C). 400,000 years ago, every single part of the Universe was uniformly ~2800 C (there was no empty, cold space).

[Arp220]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
What are your credentials?

[/ QUOTE ]

I'm not claiming to know everything and please correct me if I'm mistaken anywhere. I took some high level astronomy/cosmology courses in college and read a bit cosmology in my spare time. I'll be able to answer most questions in layman's terms.

[/ QUOTE ]

Please explain why a specific cosmic microwave background radiation was definitive proof that the big bang theory was correct. Just curious how Georges Lemaître could have predicted that.

[/ QUOTE ]

When we look at Cosmic Background Radiation, we are actually seeing a snapshot of the Universe relatively soon after the Big Bang took place (~400,000 years after). It was the moment the Universe had cooled enough so that it went from being opaque to becoming transparent. It was also the moment energy and matter became two separate things. Anyway, this Cosmic Background Radiation is really far out and receding from us fast so it's grossly distorted (redshifted) into the microwave part of the light spectrum. But if we account for the redshift, we can determine the wavelength of the light that originally left the CBR and from that, we can determine the temperature (~2800 C). 400,000 years ago, every single part of the Universe was uniformly ~2800 C (there was no empty, cold space).

[/ QUOTE ]

This isn't exactly right. The formation of the cosmic microwave background radiation is due to an event called 'decoupling' that occurred during the epoch of recombination, a few hundred thousand years after the Big Bang. Theres a good write up of it here:

http://en.wikipedia.org/wiki/Cosmic_...ave_background

Look in the first paragraph under 'features'.

[Humble Pie]

Can or will a similar event ever take place?