Name: anthony w thompson
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: 1993 - 1999
Question:
Some questions about comets... any help would be appreciated.
What are comets composed of?
How fast do they move?
How many are known? How many can be seen?
Where are they located?
What happens to them? Do they ever die out?
What would happen if a comet hit the earth?
How big does a comet have to be to make it through the atmosphere?
How do people calculate their speed and mass?
Replies:
Comets are thought to be "dirty snowballs" composed mostly of water ice
and methane ice. They travel at speeds around 20,000 MPH. Some appear only once,
then leave the solar system or break up. Some return periodically to the inner
solar system (like Halley's). Most are thought to spend most of their time in th e Oort Cloud
(check a good encyclopedia or an astronomy text). They can only been seen when
they enter the inner solar system and reflect the light of the sun. Their tails
are produced by material evaporating off the surface. Comets do not travel throu gh the atmosphere
unless they're on a trajectory to hit the earth. If a comet hit the earth, the
results would be catastrophic: scientists think that might have been responsible
for the extinction of the dinosaurs. Their speed and mass are calculated from th eir different
positions in the sky over time.
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