For a perfect vacuum to occur, space would need to be totally devoid of all matter including energy fluctuations which exist even in empty space. Outer space has very low density and pressure, and is the closest physical approximation of a perfect vacuum. But no vacuum is truly. The vacuum of outer space is not caused by the expansion of the universe, but is caused by gravity. First of all, when we say outer space. Although gases and dust may be present in the space, huge areas of space can be called perfect vacuum because of absence of any matter. Consider huge spaces. › Outer-Space-Perfect-Vacuum › release. View credits, reviews, tracks and shop for the Cassette release of "Perfect Vacuum" on Discogs. Because outer space has very low density and pressure, it makes something very close to a vacuum — but it's still not a perfect vacuum. Practically, it is impossible to make a perfect vacuum. A perfect vacuum is defined as a region in space without any particles. The problem is that to maintain. Vacuums never “suck” air. What they do is present an empty space and then air pressure forces the air into the vacuum. Air pressure is not. Much of outer space has the density and pressure of an almost perfect vacuum. It has effectively no friction, which allows stars.