51�Թ�

A cosmological constant is a famous part of Einstein's General Relativity theory, and refers to an arbitrary constant that is present in all related field equations.

The question for theorists is: Has the growth of that cosmic yardstick accelerated steadily, in accordance with a cosmological constant, or does the acceleration vary over time?

One is that dark energy is a cosmological constant, an unchanging property of space, which would mean that the universe would continue to expand indefinitely, sweeping far-off objects forever beyond our local point of view.

One solution assumes dark energy isn’t a cosmological constant, but is due to some kind of new physics.

In a Universe explained by Einstein's theory with a cosmological constant, black holes are immersed in a cosmological accelerated background.