The cosmic triangle: Revealing the state of the universe

Neta A. Bahcall, Jeremiah P. Ostriker, Saul Perlmutter, Paul J. Steinhardt

Research output: Contribution to journalReview articlepeer-review

980 Scopus citations


The cosmic triangle is introduced as a way of representing the past, present, and future status of the universe. Our current location within the cosmic triangle is determined by the answers to three questions: How much matter is in the universe? Is the expansion rate slowing down or speeding up? And, is the universe flat? A review of recent observations suggests a universe that is lightweight (matter density about one-third the critical value), is accelerating, and is flat. The acceleration implies the existence of cosmic dark energy that overcomes the gravitational self-attraction of matter and causes the expansion to speed up.

Original languageEnglish (US)
Pages (from-to)1481-1488
Number of pages8
Issue number5419
StatePublished - May 28 1999

All Science Journal Classification (ASJC) codes

  • General


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