The Comet Nucleus



This is a drawing of what the surface of a comet might look like.
Click on image for full size version (40K GIF)
Image courtesy of JPL
A comet nucleus is made of a special sort of dust. This theorized dust is called "fluffy" because it could be as light weight and full of holes as a sponge. The holes are filled with frozen gases made of carbon dioxide, carbon monoxide and other gases. Observations of the nuclei of comet Hale-Bopp and Hyakutake have given scientists fresh ideas about comet composition and evolution.

Scientists do not know whether the nucleus is very hard (like solid ground) or very soft and breakable (like a snowball). The Rosetta mission hopes to land a probe on the surface of a comet to find out just how hard it is.

As a comet approaches the Sun, it begins to sublimate, forming the coma and a spectacular tail. This picture shows that sublimation may happen only in specific places on the nucleus. These spots of evaporation are called "jets". The jets can sometimes help to turn the comet and make it tumble in space. Halley's comet was photographed with three distinct jets on its surface as it approached the Sun in 1986.


A Table of Comet Missions


The Comet Nucleus



This is a drawing of what the surface of a comet might look like.
Click on image for full size version (40K GIF)
Image courtesy of JPL
The nucleus of a comet is the central portion of the head of a comet. It is a solid part of the comet, made of a special sort of dust which is called "fluffy" because it could be as light weight and full of holes as a sponge. The holes of this "sponge" are filled with ices like water, carbon dioxide (dry ice), and carbon monoxide (what comes out of your car).

Observations of the nuclei of comet Hale-Bopp and Hyakutake have given scientists fresh ideas about comet composition and evolution. But, scientists still don't know whether the nucleus is very hard, like solid ground, or very soft and breakable, like a snowball. The Rosetta mission hopes to land a probe on the surface of a comet to find out just how hard it is!

As a comet approaches the Sun, it begins to evaporate, forming the coma and a spectacular comet tail. This picture shows that evaporation may happen only in specific places on the nucleus. These spots of evaporation are called "jets". Halley's comet had three distinct jets on its surface as it approached the Sun in 1986.


A Table of Comet Missions


The Comet Nucleus



This is a drawing of what the surface of a comet might look like.
Click on image for full size version (40K GIF)
Image courtesy of JPL
A comet nucleus is the very center of the comet. It is solid and is made of a special sort of dust which scientists call "fluffy". They call it fluffy because it is full of holes and could be very light.

At this point, scientists do not know whether the nucleus is very hard, like solid ground, or very soft, like a snowball.

Scientists are going to use the Rosetta mission to land a probe on the surface of a comet! This and other comet missions will certainly help scientists understand the very center of comets!

A Table of Comet Missions



Last modified June 22, 2005 by Jennifer Bergman.
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