A quintessential introduction to dark energy

P. J. Steinhardt
2003 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
Most of the energy in the universe consists of some form of dark energy that is gravitationally self-repulsive and that is causing the expansion rate of the universe to accelerate. The possible candidates are a vacuum energy density (or, equivalently, a cosmological constant) and quintessence, a time-evolving, spatially inhomogeneous component with negative pressure. In this review, we focus on quintessence and ideas on how it might solve the cosmic coincidence problem, how it might be
more » ... t might be distinguished observationally from a cosmological constant, and how it may affect the overall cosmic history of the universe.
doi:10.1098/rsta.2003.1290 pmid:14667314 fatcat:i4tsyspcvzegtn7hnsq7y3rzoq