The Astronomy Book

168

A DAY

WITHOUT

YESTERDAY

HE BIRTH OF THE UNIVERSET

T

he idea that the universe

originated from a tiny object

in the form of an egg appears

in The Rigveda, a collection of Hindu

hymns from the 12th century bce.

However, there were few scientific

clues to the universe’s true origins

until Albert Einstein provided a

new way of conceiving time and

space with his general theory of

relativity in 1915. Einstein’s insight

led many to revisit the idea that

the universe started small, among

them the Belgian priest Georges

Lemaître, whose 1931 proposal

would carry echoes of The Rigveda.

In the 17th century, Johannes

Kepler, observing that the night

sky is dark, argued that the universe

IN CONTEXT

KEY ASTRONOMER

Georges Lemaître

(1894 –1966)

BEFORE

1915 Albert Einstein

publishes his general theory

of relativity, which includes

equations that define various

possible universes.

1922 Alexander Friedmann

finds solutions to Einstein’s

equations, indicating that the

universe could be expanding,

contracting, or static.

AFTER

1929 Edwin Hubble observes

that distant galaxies are

moving away from Earth

at a rate proportional to

their distance.

1949 Fred Hoyle coins

the term “Big Bang” for

Lemaître’s theory.