What is the cosmology constant?

1 Answer
Apr 1, 2016

The cosmological constant #Lambda# was the relativity constant proposed by Einstein in 1917, to see expanding/contracting universe as quasi-static. Now, #Lambda# is energy-density of vacuum.


The mysterious universe is now seen as expanding universe. It was not known a century ago that whether our universe is expanding or contracting.

So, Einstein introduced a cosmological constant to make it neither. Despite Einstein;s regret about his notion of #Lambda# (cosmological constant), the scientists' marking of 20% for Dark Energy, in our universe, might be attributed to this definition.

Note that there is no zero-density matter. Vacuum is 0+ (infinitesimal)-density matter.