Parrallel Universe Regained?

[Profpat]

Is this like saying " If it can happen, it will happen."

It is possible to have spatial inflation, therefore, you have spatial inflation.

[AntonioLao]

If time inflation does happen then my Timex wristwatch must be recalibrated in logarithmic scale.

[Graybeard]

Is this like saying " If it can happen, it will happen."

It is possible to have spatial inflation, therefore, you have spatial inflation.

Prof ... In the Quantum realm, this is probably a fair statement.

cool bananas ... greg

[dipayankar]

Hi Neutralino, If we look at Gregs post above, it seems that inflation happened in an instant. There has to be some very very strong phenomenon which would drive this expansion. I understand that this theory solves a lot of problems. But then this theory would also violate some physical phenomenon like conservation of energy. We do not know how much energy would have been used up for this inflation. I also understand that this inflation happened for a very very very short time. And also question arises as to why was inflation required at all??

I'll try and answer some of the above points:



(Emphasis mine). The reason the universe is expanding is not a problem: it's just an initial condition in the model. The universe "started out" (whatever that means) expanding, so it is still doing so today. What we don't know is why the universe appears to be accelerating in its expansion. This is where the so-called "dark energy" comes in (or, alternatively, where people modify einstein's gravity at late times).



I wouldn't say that. Inflation's quite easy to understand: it was simply a period in which the universe was accelerating in it's expansion. It was conjured up to solve several problems: the horizon problem (that areas of the CMB opposite each other had the same temperature, but had never been in causal connection, according to the non-inflationary big bang); the flatness problem (that the universe is observed to be pretty much flat today, but as a universe expands, it's curvature deviates from zero, so it must have been very very close to flat in the early universe); monopole problem (there are supposedly many topological defects, like magnetic monopoles, formed in the early universe, but we don't see them today), but is favoured today because not only does it answer the above questions, but it also gives us large scale structure: initial quantum fluctuations were enlarged into macroscopic density perturbations by inflation, which seeded the structure formation in the universe.



What question of "why" are you referring to? If you mean "why did the universe come into existence," then I would argue that it isn't the job of science to answer such a question.





Don't worry: nobody knows why inflation happened. Ideally, one would obtain an inflationary scenario from a higher theory, and for example, string theory inspired models of inflation do exist. I don't think we'll be able to answer this question for a while, though, since we don't know what the fundamental theory is!

Of course, this could be an area in which the opposite happens: cosmological observations give us a hint as to whether, for example, string theory is correct. If a string-inspired model of inflation fits the data better than a standard one (and they do give some different predictions), we may be on the way to testing string theory.

[Graybeard]

Hi Neutralino, If we look at Gregs post above, it seems that inflation happened in an instant.

There has to be some very very strong phenomenon which would drive this expansion.

I also understand that this inflation happened for a very very very short time. And also question arises as to why was inflation required at all??

I think your looking at it from the wrong end Dip. I am not sure if I am correct here, but if we imagine a time, tho time has no relevance because it does not exist yet, when the four forces were one. Then if this force was in its lowest possible energy state, and yet was not zero, then if something happened to allow it to release even more energy, to approach even closer to zero, then the result would be our Universe. Though I think gravity was actualy the repulsive force.

It was not 'required', it just happened. One possibilty. But when you say instant, large, or strong, your talking about it in retrospect. We can't say the expansion was vast and instantanous, we have nothing to compare against. We only have the one universe, and measurement (space) and time were only created in the process.

(I think ... lol )

cool bananas ... greg

[Profpat]

Hi Neutralino, If we look at Gregs post above, it seems that inflation happened in an instant. There has to be some very very strong phenomenon which would drive this expansion. I understand that this theory solves a lot of problems. But then this theory would also violate some physical phenomenon like conservation of energy. We do not know how much energy would have been used up for this inflation. I also understand that this inflation happened for a very very very short time. And also question arises as to why was inflation required at all??

Why wouldn't the energy be in the inflation of space/time, conserved.

[ggullet]

Why wouldn't the energy be in the inflation of space/time, conserved.

everything is conserved. Even at the point of percieved extinction

[ggullet]

Is this like saying " If it can happen, it will happen."

It is possible to have spatial inflation, therefore, you have spatial inflation.

if it can happen it did happen

[dipayankar]

Because we feel that the amount of energy that would be required, would be enormous that might not leave the Universe with any more energy for matter formation.

Why wouldn't the energy be in the inflation of space/time, conserved.