[1] Kuiper, the son of a tailor in the village of Tuitjenhorn in North Holland, had an early interest in astronomy.

[citation needed] He studied at Leiden University in 1924, where at the time a very large number of astronomers had congregated.

He befriended fellow students Bart Bok and Pieter Oosterhoff, and was taught by Ejnar Hertzsprung, Antonie Pannekoek, Willem de Sitter, Jan Woltjer, Jan Oort, and the physicist Paul Ehrenfest.

Kuiper received his PhD degree from Leiden University in the Netherlands on his thesis on binary stars with Hertzsprung in 1933.

In 1935 he left to work at the Harvard College Observatory, where he met Sarah Parker Fuller (1913-2000), whom he married on 20 June 1936.

In 1958, the two worked on the classified military Project A119, a secret Air Force plan to detonate a nuclear warhead on the moon.

[5] In 1951, in a paper in Astrophysics: A Topical Symposium, Kuiper speculated that a large disc of small astronomical bodies formed early in the Solar System's evolution.

Kuiper died age 68 of a heart attack on 23 December 1973 in Mexico City, while on vacation with his wife.

However Kuiper himself believed that such objects would have been swept clear by planetary gravitational perturbations, so that none or few would exist there today.