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arXiv · astro-ph/0310342

Why is the Universe Accelerating?

Sean M. Carroll
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Abstract

The universe appears to be accelerating, but the reason why is a complete mystery. The simplest explanation, a small vacuum energy (cosmological constant), raises three difficult issues: why the vacuum energy is so small, why it is not quite zero, and why it is comparable to the matter density today. I discuss these mysteries, some of their possible resolutions, and some issues confronting future observations.

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Sean M. Carroll. 2003-11-18. Why is the Universe Accelerating?. https://doi.org/10.1063/1.1848314

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