Is Cosmological Inflation the reason for the uniformity of the universe?

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Discussion Overview

The discussion revolves around the concept of cosmological inflation and its implications for the uniformity of the universe, alongside various related questions about the early universe, light behavior, quantum mechanics, and experimental setups in physics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation
  • Homework-related

Main Points Raised

  • Some participants question the validity of the claim that the universe expanded from the size of hundreds of billionths of an atom to 100 million light-years in a fraction of a second after the Big Bang.
  • There is a discussion about what happens to light when it is turned off in a closed room, with some suggesting it is absorbed and re-emitted at longer wavelengths.
  • Participants explore the idea that probing smaller scales in the universe would require a particle accelerator the size of a galaxy, with one noting the relationship between scale, energy, and size.
  • The implications of the Schrödinger's cat thought experiment are debated, particularly regarding whether the cat itself could influence the wave function collapse.
  • Some participants express interest in creating a homemade version of the double-slit experiment, sharing ideas and resources for setup.
  • There is a challenge regarding how the universe could expand faster than the speed of light, with some asserting that such expansion is consistent with relativity, which only restricts the speed of information transfer.
  • Cosmological inflation is mentioned as a theory explaining the uniformity of the cosmic microwave background and galaxy distribution, but the specifics of the physics behind this are questioned.

Areas of Agreement / Disagreement

Participants express a range of views on the questions posed, with some agreeing on certain aspects of cosmological inflation while others raise challenges and seek clarification. The discussion remains unresolved on many points, particularly regarding the implications of inflation and the nature of light and quantum mechanics.

Contextual Notes

Some claims depend on specific interpretations of physics concepts, and there are unresolved questions about the assumptions underlying the discussions, particularly regarding the nature of light and the implications of quantum mechanics.

Dav333
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Some Random questions (please help)

If its ok, I have 5 random questions Id like answered. I’ve thought about these for some time. hope its ok.

1) I read that 10-33 seconds after the Big Bang, the Universe went from the size of 100's of billionths of an atom to 100million LY across within 10-32seconds? Is this remotely true?

2) Were does all the light go when you turn off the light in a closed room? I heard it recoils to a different wavelength? Would it still be bouncing all around the room, & we just can’t see it?

3) I read to probe into the smallest scales of on the universe, a particle accelerator the size of the galaxy would be needed. Why is this?

4) With the cat in the box experiment, would the very objects in the box (cat) interfere with the experiment causing the wave function of the cats life to collapse straight away?

5) Is there anyway to make a home made version of the double slit expeirment? I would love to show some ppl. But wouldn't no were to begin.


Please excuse my lack of knowledge. Any advice is appreciated. Thank you.
 
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Dav333 said:
1) I read that 10-33 seconds after the Big Bang, the Universe went from the size of 100's of billionths of an atom to 100million LY across within 10-32seconds? Is this remotely true?
I think by 10 seconds the universe was large than an atom, but the inflationary phase when it went from pretty small to very-very big is probably correct.

2) Were does all the light go when you turn off the light in a closed room? I heard it recoils to a different wavelength? Would it still be bouncing all around the room, & we just can’t see it?
The light is absorbed by the walls and anything else in the room, it heats them up slightly and they emit a longer wavelength (infrared) photon - whether this is the 'same' light is a bit philosophical.

3) I read to probe into the smallest scales of on the universe, a particle accelerator the size of the galaxy would be needed. Why is this?
Basically the smaller scale -> higher energy -> larger size.
One interesting take is that since the limit is an accelerator the size of the universe, and since the universe is expanding - we had better start building it now before the price goes up!

4) With the cat in the box experiment, would the very objects in the box (cat) interfere with the experiment causing the wave function of the cats life to collapse straight away?
From a cat lovers point of view - the cat is a perfectly good observer!
The point of the experimeent wasn't to kill cats - it was to point out that quantum effects (the decay of a particle) had real world consquences not knowing if the cat was alive or dead.
It was to overcome objections to quantum mechanics that it all happened on very small scales and wasn't real-world.

5) Is there anyway to make a home made version of the double slit expeirment? I would love to show some ppl. But wouldn't no were to begin.

this describes a setup http://www.personal.psu.edu/faculty/r/e/ref7/apparatus/2003 competition/wonnel-DA-LC.htm
Personally I found an easier way to make the slit is to put a hair between two razor blades and use a laser pointer.
 
Last edited:
mgb_phys said:
since the universe is expanding - we had better start building it now before the price goes up!

:smile::smile:
Going for the ribbon this year, Mgb? :biggrin:
 
This is one of the few places where people 'get' my sense of humour - that's probably very worrying!
 
You should be worried; the volcano is waiting...
 
Dav333 said:
If its ok, I have 5 random questions Id like answered. I’ve thought about these for some time. hope its ok.

1) I read that 10-33 seconds after the Big Bang, the Universe went from the size of 100's of billionths of an atom to 100million LY across within 10-32seconds? Is this remotely true?

2) Were does all the light go when you turn off the light in a closed room? I heard it recoils to a different wavelength? Would it still be bouncing all around the room, & we just can’t see it?

3) I read to probe into the smallest scales of on the universe, a particle accelerator the size of the galaxy would be needed. Why is this?

4) With the cat in the box experiment, would the very objects in the box (cat) interfere with the experiment causing the wave function of the cats life to collapse straight away?

5) Is there anyway to make a home made version of the double slit expeirment? I would love to show some ppl. But wouldn't no were to begin.


Please excuse my lack of knowledge. Any advice is appreciated. Thank you.


How could the universe grow to a distance greater than c x time in the given time ? 30 seconds should yield 30 light-seconds ? 'splain it to me, lucy
 
regor60 said:
How could the universe grow to a distance greater than c x time in the given time ? 30 seconds should yield 30 light-seconds ? 'splain it to me, lucy

The universe can expand faster than the speed of light (and almost certainly did)
Relativity just says information cannot travel faster than light and so you can no longer observe the part of the universe outside your observable sphere.
 
mgb_phys said:
The universe can expand faster than the speed of light (and almost certainly did)
Relativity just says information cannot travel faster than light and so you can no longer observe the part of the universe outside your observable sphere.

OK. What is the physics that describes that ?
 
Cosmological inflation is the theory that the universe expanded rapidly - it explains why the microwave background and distribution of galaxies is so uniform.

Special relativity says that you can't send information faster than light.
 

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