-
Asked by lwebb to Adam, Geoff, Rob, Sheila, Suzie on 21 Mar 2011 in Categories: General.
-
Suzie Sheehy answered on 17 Mar 2011:
Very good question – the ‘vaccuum’ isn’t really a vaccum because in quantum mechanics we can have what are called ‘virtual’ particles. These particles just borrow some energy from the universe and then very very quickly pay it back before the universe notices. It’s really strange, but it means that there are particles popping into existence all the time – so you can’t ever really say you have a vacuum!
-
-
Adam Tuff answered on 18 Mar 2011:
The big problem is you have to reduce the temperature to zero degrees kelvin – absolute zero – it is practically impossible to isolate something from the environment, and therefore almost impossible to stop particles getting in, especially things like weakly interacting particles like neutrinos.
-
Sheila Kanani answered on 18 Mar 2011:
Wow lwebb you are on fire 😀
I think the problem in having an absolute vacuum is that it is supposed to have ‘nothing’ in it, but you can’t see or tell if there is nothing in it because what is nothing anyway?
Also, if there is no mass in there, then there is no energy, and that goes against the conservation of energy I think.
But also it depends what sort of vacuum you are talking about.
The classical vacuum could in theory be absolutely empty when there are no particles in it so if I built a box in deep space where there is about one atom per cubic metre and did not catch that atom it would be a pretty good vacuum. Particle wise the box could screen out the cosmic microwave background radiation and if I cooled the box down to almost absolute zero it would be an absolute vacuum, but I think as soon as it starts to heat up again then it would no longer be an absolute vacuum.
So basically, I’m not sure 😀 -
Robert Simpson answered on 21 Mar 2011:
To start with it is mechanically difficult to create a true vacuum. Even in space there is radiation from the Sun pushing particles past you all the time. If you did find a totally empty region of space out there in the distant universe then even that would have things in it because the universe teems with activity at the quantum level. There are constantly particles jumping in and out of existence, sometimes reacting in between and releasing energy. This ‘quantum foam’ permeates all of the universe and is everywhere, even if it is very tiny.
Comments