# Thread: Absolute Zero

1. Originally Posted by ubiquitous1
Since time is a measurement, I would think the density property of real numbers would apply; meaning time would be continuous. However, if you ever find the elusive absolute 0, you may find a point where time is not continuous.
Okay. Time to get the elephant gun and capture this zero!!!!

2. Originally Posted by Antimony
Would all motion stop, all over the world, if we reached it here on earth?

My chemistry teacher was telling us about how some people are worried that if they reached absolute zero that will happen. Of course, someone asked "what if it were in a closed container". His response was that would mean the container would have to be the same temperature, and the surrounding particles would have to be, and it would continue onward.
Well, when you consider that heat itself is the motion of atoms, (even in "at rest" objects) then yes, in absolute zero, there would be no motion. And then, "motion" can only be defined relative to other objects anyway.

Originally Posted by Litvyak
OK guys, something has stuck in my head (ouch). How cold is it on a black hole's event horizon?
I would think it would be pretty hot from all the superheated gases streaming in, plus all the focused (from being caught in orbits), blueshifted photon radiation (which would likely push all light into the UV/X/Gamma range). That's what would vaporizes us long before we could enter a black hole!

3. Originally Posted by Litvyak
OK guys, something has stuck in my head (ouch). How cold is it on a black hole's event horizon?
I don't think you can measure the temperature of an event horizon since it isn't tangible.

Just outside the event horizon, it's typically hot due to all the matter being sucked in. If there was no matter to suck in, I would imagine it would be pretty cold, but no colder than any other point in "empty" space.

4. Originally Posted by Lateralus
I don't think you can measure the temperature of an event horizon since it isn't tangible.

Just outside the event horizon, it's typically hot due to all the matter being sucked in. If there was no matter to suck in, I would imagine it would be pretty cold, but no colder than any other point in "empty" space.
If theres no matter to pull into the black hole, there would not be any motion either, so would mean absolute zero. Unfortunately, Stephen Hawking had said that black holes emit radiation which supprisingly enought is call "hawking radiation."

From what i got from his explanation, "hawking radiation" is from the black hole body and cause by mass escaping the black hole via quantum effect. I don't understand enough of quantum mechanic to get into details, when i try to read a book about it...all i see are equations which you need calculus to understand. I'm trying to learn calculus by myself to understand QM, but it's a tiring task sigh.

5. Originally Posted by forzen
If theres no matter to pull into the black hole, there would not be any motion either, so would mean absolute zero.
You're forgetting about photons. I suppose I should have said particles with mass.

6. Originally Posted by Lateralus
You're forgetting about photons. I suppose I should have said particles with mass.
A black hole would pull everything including light, so i was under the impression that it would be empty space, meaning not even light would be present.

7. Originally Posted by Antimony
Would all motion stop, all over the world, if we reached it here on earth?

My chemistry teacher was telling us about how some people are worried that if they reached absolute zero that will happen. Of course, someone asked "what if it were in a closed container". His response was that would mean the container would have to be the same temperature, and the surrounding particles would have to be, and it would continue onward.
Matter is densely compact energy.

Energy is defined by motion.

Kelvin is a temperature unit which is directly proportional to kinetic energy.

Therefore, zero Kelvin = zero energy = zero motion.

So yes, in short, there would be no motion, no matter, no nothing, if something were to reach absolute zero. Reaching absolute zero cannot be done. It's an asymptote and will never be crossed.

It doesn't make much sense to say something reaches absolute zero, because once absolute zero is reached, there are no somethings left; all you have is nothing.

8. Originally Posted by Antimony
Would all motion stop, all over the world, if we reached it here on earth?

My chemistry teacher was telling us about how some people are worried that if they reached absolute zero that will happen. Of course, someone asked "what if it were in a closed container". His response was that would mean the container would have to be the same temperature, and the surrounding particles would have to be, and it would continue onward.
That sounds a bit silly. If you had a hypothetical bowling ball at absolute zero temperature, and threw a tennis ball at it, some of the energy would transfer over on impact. And if the bowling ball couldn't absorb any energy for some reason, then the tennis ball wouldn't have had any energy leeched away by the interaction and the effect would be nothing. Point being, such an object wouldn't destroy the universe.

9. Originally Posted by ubiquitous1
Since time is a measurement, I would think the density property of real numbers would apply; meaning time would be continuous. However, if you ever find the elusive absolute 0, you may find a point where time is not continuous.
The density property of real numbers doesn't apply to measurements, not in an absolute sense anyway. In fact the density property is one of the least "realistic" properties of the real numbers.

10. Originally Posted by The_Liquid_Laser
The density property of real numbers doesn't apply to measurements, not in an absolute sense anyway. In fact the density property is one of the least "realistic" properties of the real numbers.
Really? I don't understand why it wouldn't apply,but I guess I'll learn when I take discrete math. Thank you

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