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Comet Halley
Comet Halley (click to enlarge)

Comet Halley
Date: 14 Mar 1986

In 1986, the European spacecraft Giotto became one of the first spacecraft ever to encounter and photograph the nucleus of a comet, passing and imaging Halley's nucleus as it receded from the sun. Data from Giotto's camera were used to generate this enhanced image of the potato shaped nucleus that measures roughly 15 km across. Some surface features on the dark

Every 76 years Comet Halley returns to the inner solar system and each time the nucleus sheds about a 6-m deep layer of its ice and rock into space. This debris shed from Halley's nucleus eventually disperses into an orbiting trail responsible for the Orionids meteor shower, in October of every year, and the Eta Aquarids meteor shower every May.

What Scientists/Engineers Say About This Image:

"Going back further in time, ESA's Giotto mission to comet 1P/Halley was a milestone, showing for the first time that comets have nuclei. This was the first time a spacecraft came close enough to look through the fog surrounding a comet. Hard to believe that was only in 1986."

--Peter Jenniskens: Research Scientist, SETI Institute and NASA Ames Research Center

(Read More of what Peter Jenniskens has to say about this and other significant events by clicking here.)

"Data from Giotto's camera, which used an automated targeting system, included a spectacular image of the potato shaped nucleus that measures roughly 15 km across. What surprised everyone was that the nucleus was not a snow-white ice ball, but dark as a lump of coal. Some craggy surface features and craters could be seen, and jets of gas and dust streaming into Halley's coma. This was the first-ever image of a "primitive body," and a highly active one at that. The automated targeting device was even fooled, homing in on a jet coming off the dark surface as the spacecraft flew past (rather than the surface itself, which was expected to be bright). Data obtained on the composition of single comet grains discovered something new -- grains of pure organic material or "CHON" -- and nothing else, proving that comets are largely organic material rather than snowballs!"

--Jeff Cuzzi: Research Scientist, NASA Ames Research Center

(Read More of what Jeff Cuzzi has to say about this and other significant events by clicking here.)

Credit: Halley Multicolor Camera Team, Giotto Project, ESA

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Last Updated: 5 Mar 2014