Vacuums, such as the vacuum of space, contain no matter of any type. Usually, one thinks of the vacuum as having no atmosphere (essentially negligible pressure) but there's a lack of solids or liquids as well.[1] The vacuum does however often contain photons. This doesn't stop it from being a vacuum, because photons do not contain matter—just energy. This is how the vacuum can still exist at some temperature above absolute zero: the photons allow it to have that thermal energy without having matter. See Figure 1 to see the vacuum of space.

Figure 1. A picture of the atmosphere taken from the International Space Station over the Indian Ocean, the black in the upper right hand side is the vacuum of space.[2]

For Further Reading


  1. Law and R. Rennie, A dictionary of physics. Oxford: Oxford University Press, 2015.
  2. NASA, accessed: on August 26th, 2018.

Authors and Editors

Bethel Afework, Allison Campbell, Kailyn Stenhouse, Jason Donev
Last updated: September 3, 2018
Get Citation