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Dark Energy

Media Telecon:

Dec. 16, 2008 (1 p.m. EDT)

For the first time, astronomers have clearly seen the effects of dark energy on the most massive collapsed objects in the Universe using NASA's Chandra X-ray Observatory. By tracking how dark energy has stifled the growth of galaxy clusters and combining this with previous studies, scientists have obtained the best clues ever about what dark energy is and what the destiny of the Universe could be.

-Press Release

Live audio of the teleconference will be streamed online at: Instant replays are generally available one hour after a call ends, and will be through December 23, 2008 10:59 PM (CT)
Toll Free: 800-839-1248
Toll: 203-369-3356

A video file about the discovery will air on NASA Television on December 16 at noon and 1pm (check the NASA TV schedule for additional times and information).


Alexey Vikhlinin, (Astrophysicist, Smithsonian Astrophysical Observatory, Cambridge, Mass. )
William Forman, (Astrophysicist, Smithsonian Astrophysical Observatory, Cambridge, Mass.)
David Spergel, (Theoretical astrophysicist, Princeton University)
Bios Page


Evidence for Dark Energy Illustration
Figure 1.The evolution of the Universe.

Figure 2. Image from NASA's Wilkinson Microwave Anisotropy Probe (WMAP)

Stills from Diemand simulation
Figure 3. Stills from simulation showing structures growing with cosmic time (Diemand et al).

Abell 85, SDSS optical and Chandra X-ray
Figure 4.The galaxy cluster Abell 85: SDSS optical (left) and Chandra X-ray (right).

6-panel of Chandra images

Figure 5. A sample of Chandra galaxy cluster images: local (left) and distant (right).

Dark Matter1
Dark Matter2
Dark Matter3
Figure 6. "Measuring" the Universe by weighing galaxy clusters.

Supplementary Graphics

Comparing the expansion of the Universe with its growth

Mass-energy distribution of the Universe

Additional Information

Paper Title: Chandra Cluster Cosmology Project III: Cosmological Parameter Constraints (pdf format)

Full Author List: A.Vikhlinin (SAO & IKI, Moscow), A. Kravtsov (Chicago), R. Burenin (IKI, Moscow), H. Ebeling (Hawaii), W. Forman (SAO), A. Hornstrup (NSI, Copenhagen), C. Jones (SAO), S. Murray (SAO), D. Nagai (Yale), H. Quintana (PUCdC, Santiago), A. Voevodkin (IKI, Moscow; LANL)

Scientist Contact Information:
Alexey Vikhlinin:
Bill Forman:
David Spergel:
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