? do comets have water? what info is used to decide?

Question

? do comets have water? what info is used to decide?

Answer 1

Yes, comets are made of lumps of ice and compressed gasses.

How do we know? The ice melts and gasses are released when it's close to the sun, forming a "tail" we all know and love.

Answer 2

Comets have ice, but not liquid water.  When they get in the vicinity of the sun, however, a coma develops and everything changes. The dust in the coma reflects sunlight, and gas in the coma absorbs ultraviolet radiation and begins to glow. The comet starts to look like a big "fuzzy ball". This coma material is then blown away from the coma by the solar wind and becomes the comet's tail. Comet tails can stream out up to 100 million km in length! However, the density of material in the tail is not very large.

The tail of the comet  is the result of energy from the sun reaching the comet and either melting water ice or sublimating sold carbon dioxide (dry ice) along with the subsequent release of organic molecules which had

been held in the structure.

Several mission have flown through a comet's tail and lived to tell about it. The International Sun-Earth Explorer 3 (ISEE-3) spacecraft, renamed the International Cometary Explorer (ICE), made the first ever direct cometary measurements on September 11, 1985 as it flew through the tail of Comet Giacobini-Zinner. The space craft encountered a comet ion tail about 25,000 km wide. Water and carbon monoxide ions were identified, which confirmed the "dirty snowball" theory.

Answer 3

They're made from ice and rocks etc,

So yes, but I'm guessing it'd evaporate because of the temperature it's facing when it shoots to it's destination ♪