2. NAME- BHARAT AGGARWAL
CLASS- 8TH B
ROLL- 16
SUBJECT OF PRESENTATION- ASTEROIDS
AND COMETS

3. Today I am going to tell you about
asteroids and comets.
They are generally large floating stones in
a particular path
Lets learn a little bit about them

4. By bharat aggarwal

5. 1. Small objects in the solar system are
leftovers that never accreted into planets
2. Minor planets mostly orbit between Mars
and Jupiter
3. Comets formed in the outer solar system
and were flung outward by close
encounters with other planets
4. Comets can be trapped in the inner solar
system by planetary encounters
5. The head and tail of a comet glow from
sunlight shining on gases evaporated from
the comet
6. Meteors and meteorites are pieces broken
off larger bodies by collisions, or dust shed
by comets
7. Occasionally comets or minor planets
collide with larger objects like the earth

6.  Asteroids: within the orbit of Jupiter
 Centaurs: Between Jupiter and Neptune
 Kuiper Belt Objects (KBO’s): Beyond Neptune
 Scattered Disk: Extreme KBO’s
 Comets: Icy bodies with elongated orbits
 Meteoroids: Small objects
 Meteors: vaporize in Earth’s atmosphere
 Meteorites: survive to reach surface
1. Small objects in the solar system are
leftovers that never accreted into planets

7.  Vulcan
 Hypothetical planet within the orbit of Mercury
 Some asteroids and many comets cross the orbit of
Mercury, but nothing is known to orbit entirely
within the orbit of Mercury
 Planet X
 Hypothetical massive outer planet beyond Neptune
 Nemesis
 Hypothetical dwarf star companion to Sun

8. Asteroid

10.  Asteroid are a class of small Solar System bodies in orbit around
the Sun. They have also been called planetoids, especially the
larger ones. These terms have historically been applied to any
astronomical object orbiting the Sun that did not show the disk of
a planet and was not observed to have the characteristics of an
active comet, but as small objects in the outer Solar System were
discovered, their volatile-based surfaces were found to more
closely resemble comets, and so were often distinguished from
traditional asteroids. Thus the term asteroid has come increasingly
to refer specifically to the small bodies of the inner Solar System
out to the orbit of Jupiter, which are usually rocky or metallic.
They are grouped with the outer bodies—centaurs, Neptune
Trojans, and trans-Neptunian objects—as minor planets, which is
the term preferred in astronomical circles. This article will restrict
the use of the term 'asteroid' to the minor planets of the inner
Solar System.

13. Asteroids Year
1 1801
100 1867
500 1902
1,000 1921
2,000 1942
5,000 1972
10,000 1981
20,000 1993
50,000 1999
100,000 2000
200,000 2003
2. Minor planets mostly orbit between Mars
and Jupiter

14.  535789 Minor planets catalogued
 251651 Officially numbered
 16154 Named
2. Minor planets mostly orbit between Mars
and Jupiter

15.  Spacecraft
 Ground-Based and Hubble Imaging
 Radar Imaging
2. Minor planets mostly orbit between Mars
and Jupiter

16. 2. Minor planets mostly orbit between Mars
and Jupiter

23. 2. Minor planets mostly orbit between Mars
and Jupiter

26. 2. Minor planets mostly orbit between Mars
and Jupiter

29. 2. Minor planets mostly orbit between Mars
and Jupiter

31. 3. Comets formed in the outer solar system and were flung outward by close encounters with other planets

33. A comet is an icy small solar system body(SSSB)
that, when close enough to the sun, displays a visible
coma(a thin, fuzzy, temporary atmosphere) and
sometimes also a tail. These phenomena are both due
to the effects of solar radiation and the solar wind
upon the nucleus of the comet. Comet nuclei range
from a few hundred meters to tens of kilometers
across and are composed of loose collections of ice,
dust, and small rocky particles. Comets have been
observed since ancient times and have traditionally
been considered bad omens.

34.  Short Period (<200 years)
Record reobserved comet is Comet Ikeya-Zhang
 Long Period (>200 years)
 Hale-Bopp (2400 years)
 Need a source very far away
 Oort Cloud
 Too little material very far from the Sun
 Flung out by planetary encounters
3. Comets formed in the outer solar system and were flung outward by close encounters with other planets

35.  Ice and Frozen Gases
 Outer Solar System (Kuiper Belt)
 Planetary Encounters perturb Orbits
 Diverted inward to become short-period
 Diverted outward to Oort Cloud
3. Comets formed in the outer solar system and were flung outward by close encounters with other planets

36. 3. Comets formed in the outer solar system
and were flung outward by close encounters
with other planets

37. 4. Comets can be trapped in the inner solar system by planetary encounters

39.  Most-observed comet in history
 Discovered the furthest from the Sun
 Largest cometary nucleus known
 Visible to the naked eye for 18 months – twice
the previous record
 Brighter than magnitude 0 for eight weeks,
longer than any other comet in the last
thousand years.
5. The head and tail of a comet glow from sunlight shining on gases evaporated from the comet

40. 5. The head and tail of a comet glow from sunlight shining on gases evaporated from the comet

41. 5. The head and tail of a comet glow from
sunlight shining on gases evaporated from the
comet