In cosmology, phantom energy or phantom dark energy[1] is a hypothetical form of dark energy. It possesses negative kinetic energy, and predicts expansion of the universe in excess of that predicted by a cosmological constant, which leads to a Big Rip. The idea of phantom energy is often dismissed, as it would suggest that the vacuum is unstable with negative mass particles bursting into existence.[2] The concept is hence tied to emerging theories of a continuously created negative mass dark fluid, in which the cosmological constant can vary as a function of time.[3][4] It is a special type of quintessence.
^Carroll, Sean (September 14, 2004). "Vacuum stability". Preposterous Universe Blog. Retrieved February 1, 2019.; however, note that the preceding source also contains a link to another blog post on the same blog (a post dated one day earlier!) that also discusses (a lot) the topic of "", etc.; therefore, [feel free to] "see also": Carroll, Sean (September 13, 2004). "Phantom Energy". "Preposterous Universe" [blog]. Archived from the original on October 28, 2014. Retrieved November 2, 2020.