-2
$\begingroup$

Is a vacuum the same as 'outer space'?

When The Big Bang is described the terminology used is that 'space (itself) is expanding'.

If that's true what happens when the volume of a container, 'containing' a vacuum, is increased? Is space literally expanding in that container?

$\endgroup$
  • 3
    $\begingroup$ Please only ask one question per post. $\endgroup$ – lsusr Jun 11 at 23:18
1
$\begingroup$

If that's true what happens when the volume of a container, 'containing' a vacuum, is increased? Is space literally expanding in that container?

No, for the reason that the metric of space hasn't changed when the container volume is increased, i.e., the measured distance between two points within the container is the same before and after container volume increases.

This isn't the case for the metric expansion of space:

The expansion of the universe is the increase of the distance between two distant parts of the universe with time. It is an intrinsic expansion whereby the scale of space itself changes. The universe does not expand "into" anything and does not require space to exist "outside" it. Technically, neither space nor objects in space move. Instead it is the metric governing the size and geometry of spacetime itself that changes in scale.

(emphasis mine)

$\endgroup$
  • $\begingroup$ The two points being measured inside the container ... are they measured from outside the container? ... a different frame? What changes inside the container when it expands? "Instead it is the metric governing the size and geometry of spacetime itself that changes in scale." Isn't this what I said? ... that there's really no such thing as space ... it's really the distance between things ... just as there's no such thing as time, it's really the number of events between events. $\endgroup$ – Randy Zeitman Jun 12 at 4:35
0
$\begingroup$

No, a vacuum is not the same as outer space. That's because outer space is not empty:

Outer space, or just space, is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays.

$\endgroup$
0
$\begingroup$

If you enlarge a container that has a vacuum in it, yes you have a larger container. The available space in it is greater, however you still have nothing in it. Outer space is not a perfect vacuum, there are thinly scattered gas and dust particles.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.