manvirsingh said:
manvirsingh said:
), then according to the original EFE the universe cannot be static; it must be either expanding or contracting. There are other reasons to believe that the universe is not contracting, so the original EFE basically predicts that the universe is expanding. At the time, the universe was believed to be static, so Einstein added the cosmological constant term to the EFE to allow static solutions with non-zero stress-energy.The general theory of relativity is a theory of gravity developed by Albert Einstein in 1915. It explains how gravity works as a curvature of space and time caused by the presence of massive objects.
According to the general theory of relativity, the universe is expanding because the space between galaxies is stretching. This is due to the presence of dark energy, a mysterious force that is causing the expansion to accelerate.
One of the key pieces of evidence for the expanding universe comes from the observation of distant galaxies. The light from these galaxies is redshifted, meaning that the wavelengths of light are stretched. This is consistent with the idea of an expanding universe.
No, the general theory of relativity alone cannot explain the expansion of the universe. In order to account for the observed acceleration of the expansion, dark energy is needed. However, there are ongoing efforts to develop alternative theories that could explain the expansion without the need for dark energy.
The expanding universe suggests that the universe will continue to expand indefinitely, and the expansion will likely accelerate. This means that the distance between galaxies will continue to increase, and eventually, the universe will become extremely spread out and cold.