The Small Particle That Started The Big Bang

[S.Vasojevic]

One of the models of the universe has it wrapping around, so that heading off in one direction will have you eventually arrive back at your starting point. (Again, the balloon analogy works this way.) This is a universe that has a measurable diameter, yet has no boundary and nothing outside it.

But where we stand now, it is also the model which is less likely to be true. It appears to be flat, thus infinite.

 

[Pattonias]

But isn't this pure theory, can you give me reference, because their must be something that I need to read - instead of picking up this idea one piece at a time?

What would indicate that the edge of the universe loops around to the other side, and what difference would it make if it did?

 

[S.Vasojevic]

One model has finite content, other infinite.

 

[Pattonias]

One note, the auto-link --> edge of the universe does not really help to make this clear so If you could point me to a particular reference, that would be helpful.

 

[S.Vasojevic]

try this:http://www.astro.ucla.edu/~wright/cosmo_03.htm"

 

[DaveC426913]

But isn't this pure theory, can you give me reference, because their must be something that I need to read - instead of picking up this idea one piece at a time?

What would indicate that the edge of the universe loops around to the other side, and what difference would it make if it did?

The difference it makes is that it shows that there is no "place outside of the universe into which the universe is growing".

Sorry, I don't have any references available right now.

 

[S.Vasojevic]

The difference it makes is that it shows that there is no "place outside of the universe into which the universe is growing".

You have to put that bubble somewhere. I, on the other hand, think that flat universe solves that issue very nicely.

 

[Pattonias]

Does our Universe give some sign that there are no other universes that exist (somewhere else) that could have originated by a big bang or other matter generating event?

 

[S.Vasojevic]

We can only speculate about other universes. No physical evidence exists.

 

[Pattonias]

Thank you S. Vasojevic for the reference, it is making this a little easier to understand.

Are there particles or masses in the Universe that are more or less sensitive to gravity than others?

For instance, I have heard it said that light has no mass, yet it can be trapped by a black hole. Is it possible that it is only sensitive to extreme gravity?
For instance, the slight bend of a beam of light as it passes near a star. Is it possible that light is actually unaffected by gravity below a certain strength or that gravity below a certain strength has no effect on certain particles at all?

Does the intensity of a gravity actually affect the speed at which it reaches out to an object?

 

[Dmitry67]

no, light is affected by very low gravity too, for example, by Sun
Another examples:
http://en.wikipedia.org/wiki/Gravitational_lens

 

[S.Vasojevic]

Are there particles or masses in the Universe that are more or less sensitive to gravity than others?

No. Gravity affects everything.

For instance, I have heard it said that light has no mass, yet it can be trapped by a black hole. Is it possible that it is only sensitive to extreme gravity?
For instance, the slight bend of a beam of light as it passes near a star. Is it possible that light is actually unaffected by gravity below a certain strength or that gravity below a certain strength has no effect on certain particles at all?

Light is affected by gravity. There is no threshold of sensitivity. Smaller the potentials -smaller the result.

Does the intensity of a gravity actually affect the speed at which it reaches out to an object?

Not at all. Gravity propagates at C, same speed as light do.

 

[DaveC426913]

Not at all. Gravity propagates at C, same speed as light do.

Well...

Gravity does not travel at all. Gravity is a field, which means it is always everywhere, all the time. Changes in gravity do, however, propagate at the speed of light.

 

[Pattonias]

Well...

Gravity does not travel at all. Gravity is a field, which means it is always everywhere, all the time. Changes in gravity do, however, propagate at the speed of light.

That makes sense, I have seen gravity described as a fabric and the fluctuations in gravity around a black hole as ripples in this fabric. (Feel free to disect this statement, but I was putting no weight into it )

 

[DaveC426913]

The difference it makes is that it shows that there is no "place outside of the universe into which the universe is growing".

You have to put that bubble somewhere.

No, you don't.

 

[S.Vasojevic]

Official WMAP site:

WMAP nailed down the curvature of space to within 1% of "flat" Euclidean, improving on the precision of previous award-winning measurements by over an order of magnitude

No, you don't.

That doesn't even matter. Question is, is it curved or is it flat, and we will probably never know. If we could measure its curvature we can exclude it being flat, but not the other way around. Even when some future measurement comes out saying "flat-Euclidean within 0.1%", we could always say that curvature is so slight that it lays within error margin.
It is again Nature playing tricks on ourselves. You want to know do you live in finite or infinite universe? You will have to try much harder than that.