This document provides an overview of comets and their importance. It begins with a brief introduction describing comets as "dirty balls of ice" with tails that form when they pass by the sun. It then discusses the historical observations of comets and modern scientific study of their structure and composition. The document outlines that comets are composed of an icy nucleus surrounded by a coma of gas and dust, and that studying their composition provides insights into the early solar system. It concludes by summarizing several past and present space missions that have visited and imaged comets to learn more about their properties.

1. Minor bodies of the solar system:
Comets and their importance
Ramiz Ahmad
IIST, Trivandrum

2. Plan of the talk:
•Introduction
•Historical view point
•Structure of comets
•Origin.
•Reasons for studying comets
•Missions for comets
•Conclusion

3. Introduction:
Comets: Dirty Balls of Ice
They look like a star
with a ghostly white
tail.
The term "comet"
derives from the
Greek aster kometes,
which means "long-
haired star"---a
reference to the tail.

4. Comets: Dirty Balls of Ice
•They can be seen by us only when they pass by the sun
and the sun’s heat melts them.
•The comet's tail is made of material from the comet; gas
from the ices and dust that is mixed in with the ice. They
escape as the comet melts.
•The tail always points away from the sun due to the
solar winds (movement of heat away from sun)

5. History
• The history of comet watching dates back to 1000 BC
from the Chinese records and Chaldea, a place in
present Iraq.
• Comets have been regarded as omen, even as recently
as 1986.
• Today Astronomer study Comets from scientific
perspectives, and our understanding of these fascinating
objects have grown tremendously.

6. Structure of Comets:

7. • The icy, hard part of the comet is called the nucleus. As
the comet melts, sometimes large chunks of ice break off
in a hurry and large amounts of gases escape at once and
cause a bright “outburst”.
• The gas and dust are released and form an atmosphere
around the comet called the coma.

9. Importance of studying Comets:
• The study of the composition of the comets gives an idea
of the composition of the solar system in the early stages of
the solar system.
•Life on earth is theorized to have been seeded by the
comets. A detailed study will provide with sufficient
evidence to either support or reject the theory.

10. Missions for comets
•New Horizons - NASA Pluto and Kuiper Belt mission
•Deep Impact/EPOXI - NASA Flyby of Comets
P/Tempel 1 and Hartley 2 (2005)
•Rosetta - ESA Mission to Comet Churyumov-
Gerasimenko (2004)
•CONTOUR - NASA Mission to fly by three comet
nuclei (2002)
•Genesis - NASA Discovery Solar Wind Sample Return
Mission (2001)
•Stardust - NASA Discovery Mission to collect samples
from Comet P/Wild 2 (1999)

11. •Deep Space 1 - NASA Flyby Mission to comet Borrelly
and asteroid Braille (1998)
•Galileo - NASA Mission to Jupiter, imaged Comet
Shoemaker-Levy 9 Impact (1989)
•Giotto - ESA mission to Comets Halley and Grigg-
Skjellerup
•ICE (ISEE-3) - NASA Mission to Comet Giacobini-
Zinner
•Sakigake - Japanese ISAS mission to Comet Halley
•Suisei - Japanese ISAS mission to Comet Halley
•Vega 1 - Soviet mission to Venus and Comet Halley
•Vega 2 - Soviet mission to Venus and Comet Halley

12. References:
• www.wikipedia.org
• Chapman, C. R.; Morrison, D.; Zellner, B. (1975).
"Surface properties of asteroids: A synthesis of
polarimetry, radiometry, and
spectrophotometry". Icarus 25 (1): 104–
130. Bibcode 1975Icar...25..104C.doi:10.1016/0019-
1035(75)90191-8.
• http://solarsystem.nasa.gov/
• "Lagrange Points" by Enrique Zeleny, Wolfram
Demonstrations Project.

13. Thank You for your Patience!!!