WHAT IS COSMOLOGICAL CONSTANT?
The cosmological constant (usually denoted by the Greek capital letter lambda: Λ) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. After the discovery of the Hubble redshift and the introduction of the expanding space paradigm, Einstein abandoned the concept. However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant. The cosmological constant Λ appears in Einstein’s modified field equation in the form where R and g pertain to the structure of spacetime, T pertains to matter (thought of as affecting that structure), and G and c are conversion factors which arise from using traditional units of measurement. When Λ is zero, this reduces to the original field equation of general relativity. When T is zero, the field equation describes empty space (the vacuum). Astronomical observations imply that the constant cannot exceed 10-46 km-2.[1] The cosmological constant
