|
|
QUESTION: I am a bit confused with the word "vacuum". In a discussion at work we could
not arrive at any conclusion.
Out in space (eg, at the International Space Station 400km above the earths
surface) there is no atmosphere, and certain amount of gravity.
Now, is there a vacuum or just no pressure (space)?
Is space a vacuum ?
I am under the impression that vacuum is the opposite to pressure.
The astronauts have their suits pressurised to about 14.7psi to simulate
earths atmosphere.
I have heard of the "Black Holes" being a gigantic vacuum !
Any basic assistance will be greatly appreciated
ANSWER: For most purposes, yes. There's a slight amount of gas and dust flying
around, but unless you're trying to shove somethrough it at near-c velocities
it doesn't make much difference.
A vacuum pretty much means less than normal atmospheric pressure. There
are recognized qualities of vacuum, low vacuum, high vacuum, ultra-high
vacuum, even something like an extremely high vacuum. Each one has unique
technical challenges. An ultra-high vacuum can be spoiled by zinc from
brass fasteners evaporating! So other materials like stainless steel and
aluminum would be selected and carefully prepared and cleaned. An
extremely high vacuum can be spoiled by gasses migrating through the walls
of a stainless steel vacuum chamber, so double chambers are used with the
space between also pumped out.
There is no vacuum with a complete absence of matter. But the amount of
gas floating around can get ridiculously small.
|
|
|
|
