Which of These Statements BEST Describes the History of the Cosmological

Multiple Choice

Which of these statements BEST describes the history of the cosmological constant?

A) Einstein introduced the constant to make the universe static, but many cosmologists now believe it makes the expansion of the universe accelerate.
B) Einstein introduced the constant to make the universe expand, and it is still necessary to cosmological theories today.
C) Einstein introduced the constant to make the universe static, but Hubble's discovery of the expanding universe proved that it the constant actually vanishes.
D) Einstein introduced the constant to make the universe expand, and it is now known that it has a much higher value today because the expansion is accelerating.