Vacuum
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.
For Further Reading
- Matter and Energy
- Atmosphere
- Thermal energy
- Photon
- Absolute zero
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References
- ↑ Law and R. Rennie, A dictionary of physics. Oxford: Oxford University Press, 2015.
- ↑ NASA, accessed: https://earthobservatory.nasa.gov/images/44267 on August 26th, 2018.