# Some Random questions ( )

Some Random questions (plz 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.

mgb_phys
Homework Helper
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.

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Danger
Gold Member
since the universe is expanding - we had better start building it now before the price goes up!

:rofl::rofl:
Going for the ribbon this year, Mgb?

mgb_phys
Homework Helper
This is one of the few places where people 'get' my sense of humour - that's probably very worrying!

Danger
Gold Member
You should be worried; the volcano is waiting...

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

mgb_phys
Homework Helper
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.

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 ?

mgb_phys
Homework Helper
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.