Ask Gugel Anything About the Big Bang

[Gugel]

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- Did anything exist before the big bang?

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This is an unfair question. Did you exist in the year 1863? What did you eat for breakfast on July 23, 1863? etc. In the same way, time did not exist before the Big Bang. There is no indication that anything existed prior to the Big Bang.

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- How do we know the universe is expanding? Couldn't there be some other explanation for the redshift or whatever it is we're seeing? Couldn't we be stuck in a local random swirl of some infinite universe, like turbulence in a pond?

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When we look out into space, we see most stars receding from us. What's more, the further they are away from us, the faster they are receding. This is happening in every direction. From the current available data, it also seems that every other star/galaxy is experiencing the same phenomenon (everything is receding from it and the further away, the faster). A swirl would not exhibit these properties (a significant number of stars/galaxies would be moving in the same direction as us).

[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.

[GoodCallYouWin]

Given that almost every scientist ever has been almost completely dead wrong, how likely do you think it is that everything you "know" is completely inaccurate?

[Duke]

Regarding the expansion, I'm confused as to why this couldn't be a local phenomenon. Isn't it possible that very different behavior is being exhibited outside of our light cone? Like, we'd never see it.

Also, I was just curious if you were some sort of astronomer that I may know of. I figure anyone with the time and drive to look things up online is as good a source as any nowadays. If you had access to a good repository of recently published papers that would be pretty sweet too.

Hell, good reasoning is enough credibility for me.

[wacki]

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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.

[reb]

What is your take on the axis of evil?

[btmagnetw]

"big bang" or "the horrendous space kablooie"?

[Gugel]

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Given that almost every scientist ever has been almost completely dead wrong, how likely do you think it is that everything you "know" is completely inaccurate?

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That is definitely possible. We can see some of the big picture and we're interpreting it to mean one thing while it could really be something entirely different.

That being said, there is some very strong evidence. A mathematical derivation from Einstein's equation yields [current matter/energy density + vacuum energy + the shape of the Universe] = 1. What convinces me is that each component of the equation was individually observed. Mass density = 0.3, vacuum energy = 0.7, and the shape of the universe = 0 (flat).

Mass density gives us an indication of how dense the Universe is and was. If it was too dense early on, gravity would just suck everything back together right after the Big Bang. If it was too diffuse early on, stars/galaxies would not have enough critical mass to form. You can think of vacuum energy as a reverse-gravity. With gravity, the closer you get to something, the harder you are attracted to each other. With vacuum energy (reverse-gravity) the FURTHER AWAY you get from something, the more you are repelled. The geometries of the Universe that are generally considered possibilities include: spherical (1), flat (0), and hyperbolic/reverse sphere (-1).

[Noodles.]

[ QUOTE ]
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- Did anything exist before the big bang?

[/ QUOTE ]

This is an unfair question. Did you exist in the year 1863? What did you eat for breakfast on July 23, 1863? etc. In the same way, time did not exist before the Big Bang. There is no indication that anything existed prior to the Big Bang.
[..]


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Please, tell us about the implications of String Theory on our view of the big bang, and what was before it.

[Gugel]

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Regarding the expansion, I'm confused as to why this couldn't be a local phenomenon. Isn't it possible that very different behavior is being exhibited outside of our light cone? Like, we'd never see it.

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Yes, it could be a local phenomenon. Just the same way that when standing on the Earth it appears flat, we could be looking out in the Universe and thinking it's flat. The Universe is infinite. Our "horizon" is only 14 billion light years or so. Does our "horizon" extend far enough to view the true geometry of the Universe? We have no way of knowing for sure.