this page honors Jan Hendrik Oort (1900-1992)


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Why isn't there a picture on this page?

According to Oort's theory, there's a spherical shell of debris about half a parsec (or 1.63 light years) from the sun, and this cloud of debris is believed to be the source of millions of comets. However, no one has actually seen or photographed the Oort Cloud.

"Practically from the beginning of my study, I had been fascinated by the possibility that dynamics, which had so long been practically a monopoly of the astronomers investigating the solar system, might one day be applied to the so vastly greater systems of stars."
— Jan Oort.

Early in his career, Oort demonstrated that the Milky Way Galaxy rotates like a giant wheel, and that each of the stars in the galaxy travels independently through space.

He also determined that the sun is located toward the edge of the galaxy, and discovered the "dark matter" that is now believed to make up more than 90% of the Universe.

Jan Oort saw Halley's Comet twice, in 1910 (at the age of 10), and again in 1986.

The quotation comes from Oort's article, "Some Notes on my Life as an Astronomer," from Annual Reviews of Astronomical Astrophysics, 1981, 19:1–5, which is available for downloading from the NASA Astrophysics Data System. Thanks, NASA!