Question

is it possible to achieve a perfect vacuum (or at least 0 pressure), if not then why not?

Answer 1

I can tell you that it is currently not possible on earth, as far as in space I assume it would be possible but I'm not sure

Answer 2

No, ideal vacuum is just ideal. There is no instrument that allows someone to extract every single particle from a place. You can reach very low pressures, but then the sealings are not ideal so some air always enters the chamber (suppose we are extracting air from a chamber), and the same components of the chamber may sometimes introduce gas because of some internal process. Usually, if you want a 'good' vacumm you use a pumping machine and other fancy stuff. You can easily reach a pressure of 10^-5Torr!

Answer 3

but how does pumping machines work? I mean when you pump out the air from a room you must have lower pressure in machine but then how did that machine got low pressure, I think that by cooling down it reduces pressure, but again to cool down you need another machine that expands a gas because according to thermodynamics when a gas expands it gets cold and to do that you first had to have the gas compressed and at a certain temperature.

Answer 4

The pumping machine can work in a variety of ways. One of the most common would be a rotary pump that creates vacuum revolving one spiral within another. This causes possitive pressure in the direction of rotation and reduces pressure in the chamber.

Answer 5

Here is a nice little explanation of your original question!
http://www.physlink.com/education/askexperts/ae290.cfm

Answer 6

well thank you but still I was thinking about something like a 0 pressure box, would it really be impossible?
The real perfect vacuum is actually a very relative term, I mean, there is vacuum in between particles all the time, the atoms are mainly empty space, I heard that the nucleus of an atom would be like a fly in a stadium in comparison.
In outer space you could select a 1cubic meter and see there is actually nothing in there, maybe there are photons and neutrinos, but first, photons do not have mass nor occupy space so technically aren't matter, neutrinos are very light and barely interact with matter they wont affect pressure.
It is irrelevant to say it is 0 kelvin in temperature because temperature is only a measure for matter and vacuum is nothingness.
I guess it would be perfectly possible to just go to that 1cubic meter spot in outer space and build a box enclosing the nothing in there.

But the real question would be that if having air inside the box, would you be able to get rid of all of it?

Answer 7

Ideal vacuum is just as ideal as 0 K, no matter how small you make that box you will always enclose particles. And no matter how hard you try, you won't be able to get rid of all the air in a box. It's like physists solving ideal problems where cows are spherical! That's a long way from the real world!!

Answer 8

"But the real question would be that if having air inside the box, would you be able to get rid of all of it?" No

Answer 9

haha Marianne how about a Monkey of known mass climbing a weightless rope on a frictionless pulley attached to a weight of know mass? ^_^

Answer 10

hahahaha! the frictionless pulley has always looked reaaaally suspicious to me! xD

Answer 11

Well the fact is matter will often spontaneously appear out of nowhere and then destroy itself again in a nanosecond, so even if you managed to make a perfect vacuum it would not last very long with stuff spontaneously generating in it.