Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

March 2, 1998

Rumors of a Strange Universe
Credit: P. Garnavich (CfA) et al., WFPC2, HST, NASA

Explanation: In a meeting in California two weeks ago, unpublished results were presented indicating that most of the energy in our universe is not in stars or galaxies but is tied to space itself. In the language of cosmologists, a large cosmological constant is directly implied by new distant supernovae observations. Suggestions of a cosmological constant (lamdba) are not new -- they have existed since the advent of modern relativistic cosmology. Such claims are not usually popular with astronomers, though, because lambda is so unlike known universe components, because lambda's value appears limited by observations, and because less-strange cosmologies without lambda have historically done well in explaining the data. Therefore most lamdba claims do not make the News Summary in a prestigious journal like Science. What is noteworthy here is the seemingly direct and reliable method of the observations, and the good reputations of the scientists conducting the investigation. The above picture of a supernova at redshift 0.5 in a spiral galaxy, was taken by this collaboration. However, two teams of scientists are independently studying distant supernovae, and the last official word from the other team was a result consistent with no cosmological constant, reported just two months ago. Extraordinary claims require extraordinary evidence, and so cosmologists the world over eagerly await peer-reviewed results, further details, and more data.

Tomorrow's picture: 560 Kilometers Above Europa

< Archive | Index | Search | Calendar | Glossary | Education | About APOD >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.