Ask Gugel Anything About the Big Bang

[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.

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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.

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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).

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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'.

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every single part of the Universe was almost uniformly ~2800 C (there was no empty, cold space). If it was 100% uniform, there would not be any clumps of matter (stars, planets, etc). Those tiny "ripples" are what created all the structure in the Universe. These ripples are temperature fluctuations that are only thousandths of a degree.

[Arp220]

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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.

[/ 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'.

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every single part of the Universe was almost uniformly ~2800 C (there was no empty, cold space). If it was 100% uniform, there would not be any clumps of matter (stars, planets, etc). Those tiny "ripples" are what created all the structure in the Universe. These ripples are temperature fluctuations that are only thousandths of a degree.

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I was referring more to:

1 - glossing over the exact details of HOW the cosmic microwave background formed, which is a somewhat subtle concept. I felt it deserved some clarifying.

2 - this nonsense about "the moment energy and matter became two separate things". Sorry, but thats just [censored] ;-)

I wasnt talking about the existence of anisotropies.

[Gugel]

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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.

[/ 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'.

[/ QUOTE ]

every single part of the Universe was almost uniformly ~2800 C (there was no empty, cold space). If it was 100% uniform, there would not be any clumps of matter (stars, planets, etc). Those tiny "ripples" are what created all the structure in the Universe. These ripples are temperature fluctuations that are only thousandths of a degree.

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2 - this nonsense about "the moment energy and matter became two separate things". Sorry, but thats just [censored] ;-)

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Well, you are right in that some types of matter did exist before Recombination. There were various subatomic particles floating around. However, it was not until Recombination that the first atoms of hydrogen form.

[JuntMonkey]

The fact that there is a Universe is absolutely ludicrous. The idea of there being nothing at all is nearly as absurd. Thoughts?

[reup]

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is there any correlation between human potential and the big bang.

for example, in certain Zen teachings they talk about Kensho or certain deep realizations being earth shattering... do you think that there are ties between the conception of the Universe and earth shattering, enlightening realizations/ahah moments where ... everything is illuminated???

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As humans, we tend to place a lot of importance in our role in the Universe. In many religions, we are in the center of the Universe and are God's chosen creatures.

In reality, we are a speck in an arbitrary place in the cosmos. It is estimated that there are 10^21 stars in the Universe. If you add up all the grains of sand on all of Earth's beaches, you wouldn't be close. Furthermore, in my opinion, Man is not a special animal. We are simply a product of evolution whose brain structure allowed higher thought processes.

In short, our fate, is in no way tied to the fate of the Universe. Nevertheless, it IS truly amazing that humans can begin to understand even a little of how the Universe was created and it's laws.

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what do you have to say about mysticism. how do you explain idiot savant-ery?

[Andy Ross]

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Our "horizon" is only 14 billion light years or so.

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Did you pass your midterms? That's completely wrong.

[MrMon]

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Our "horizon" is only 14 billion light years or so.

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Did you pass your midterms? That's completely wrong.

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Explain your objection. I know what he's talking about and he's correct.

[Arp220]

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Our "horizon" is only 14 billion light years or so.

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Did you pass your midterms? That's completely wrong.

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Explain your objection. I know what he's talking about and he's correct.

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No, he's not.

[Andy Ross]

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Our "horizon" is only 14 billion light years or so.

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Did you pass your midterms? That's completely wrong.

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Explain your objection. I know what he's talking about and he's correct.

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He isn't.

14 billion years is roughly the age of the universe. The notion that this age times c gives you the radius of the observable universe is rubbish.

As of right now, the observable universe extends about 47 billion light years in each direction, due to the metric expansion of space. This is basic cosmology.

[bigpooch]

I think that's why he used "horizon" in quotes. Is this
link pertinent?

http://en.wikipedia.org/wiki/Particle_horizon


I agree there are some misconceptions as stated in the
"Misconceptions" section of the following link:

http://en.wikipedia.org/wiki/Observable_universe