Accelerating universe
From Wikinfo
[[fr:Acc�l�ration de l'expansion de l'univers]]
Accelerating universe is a term for the idea that our universe is undergoing rapid expansion. In the late 1990s, observations of type Ia supernovae produced the unexpected result that the expansion of the universe appears to be accelerating. These observations appear more firm as new data have appeared. This means that the speed with which a distant galaxy recedes from us increases over time.
If the theory is correct, the ultimate result of this trend will be an inability to see any other galaxies any more. This new theory of the end of the Universe has been called the Big Rip.
Because the energy causing the acceleration of space-time cannot be directly observed, it has been dubbed dark energy. Two theoretical candidates for this energy are a non-zero cosmological constant (which may have caused cosmic inflation) and a more general repulsive energy known as quintessence.
The observation of an accelerating universe appears to present great problems for Dyson's eternal intelligence. This theory relies on a decelerating universe, which for many years was the dominant model in cosmology, since (in the absence of observational evidence for the existence of dark energy) it was thought that the gravitational attraction of the matter in the universe to itself would act to slow the expansion.
References
- Adapted from the Wikipedia article, "Accelerating_universe" http://en.wikipedia.org/wiki/Accelerating_universe, used under the GNU Free Documentation License
