Where is the nearest vacuum in space to earth?

Answer 1

The answer may depend on what definition of vacuum an investigator uses. There really isn't any place in the universe which could be considered a complete (perfect) vacuum. Even in the largest void between galaxies, there are still a few hydrogen atoms.

The atmosphere of the Earth doesn't just stop either. We are all familiar with the air around us but the Earth's atmosphere simply gets thinner and thinner as height increases. There isn't a place where the atmosphere suddenly stops and turns into a vacuum.

Atmospheric scientists consider 5 layers of the atmosphere:

1) troposphere contacts the earth's surface and extends to about 7km upwards at the poles and 17km at the equator

2) stratosphere up to about 50 km

3) mesosphere varies quite a bit

4) thermosphere up to about 400 km

5) exosphere which simply extends out into space getting thinner and thinner. At this height molecular collisions rarely occur so temperature loses its normal meaning.

Answer 2

The nearest vacuum from Earth is in outer space itself. Space is a near-perfect vacuum, with extremely low density and pressure. It exists just beyond our planet's atmosphere.