What are benefits of light to life on earth?

What is vacuum in science?

• • A space/volume devoid/without matter, being nearly empty, sometimes called free-space. 

  • However there are always some particles but with less air than we're breathing.

• The word comes from Latin adjective vacuum for "vacant" or "void". 

• An approximation is such vacuum is region with a gaseous pressure much less than atmospheric pressure.

Vacuum and air are different:

• Air has mass, vacuum doesn't. 

• Air has pressure, can fill a balloon, vacuum can't. 

• Air  = mostly nitrogen, around 20% oxygen, a little water vapor, carbon dioxide, good enough to breathe. Vacuum has almost nothing.