Science 8

1. Prepared by:
Bb. Jasmine Nikki M. Versoza

2. COMETS
 Dirty Snowballs
 Water, dust, carbon dioxide,
ice, ammonia, methane and
more

3. COMETS
 Orbit the sun
 Can lead to meteor showers on
Earth
 Usually visible only at sunrise or
sunset

4. COMETS
 We can see a number of comets with the
naked eye when they pass close to the sun
because their comas and tails reflect sunlight
or even glow because of energy they absorb
from the sun.
 However, most comets are too small or too
faint to be seen without a telescope.

6. HEAD AND COMA
 Nucleus
 As a comet gets closer to the sun,
the ice on the surface of the nucleus
begins turning into gas, forming a
cloud known as the coma.

7. WHY DOES THE COMA APPEARS
BRIGHT?
 Reflection of the sunlight
 Emission of electromagnetic
radiation

8. THE TAIL
 Can be 150 million
kilometers in length
 Emitted from the nucleus
 Gas and dust

9. THE TAIL
 Gas tail
 Composed of ion blown out away from the sun
 Bluer, narrow and straight
 Solar wind
 Dust tail
 Dust particles
 Whiter, diffuse and curved
 Liberated from the nucleus

10. THE TAIL
 Radiation from the sun pushes dust
particles away from the coma, forming a
dust tail
 Charged particles from the sun convert
some of the comet's gases into ions,
forming an ion tail
 Comet tails always point away from the sun

11. SHORT PERIOD COMET AND
LONG PERIOD COMET

12. SHORT PERIOD COMET
 Mildly elliptical orbits
 Cannot be seen by the
naked eye

13. LONG PERIOD COMET
 Can be seen by the naked eye
 Orbits are more elongated
 Extended beyond Jupiter’s orbit

16. ASTEROID
 Minor planets
 Asteroid belt
 Ceres

17. BEGINNING OF ASTEROIDS
They might have formed
from the breakup of the
planet that once occupied an
orbit.

18. BEGINNING OF ASTEROIDS
Several larger bodies once
coexisted in close proximity
and their collisions produced
numerous smaller ones.

23. METEOROIDS
 Rocky‐metallic objects less than 100
meters
 Smaller bodies in between the planets
 Several hundred tons of meteoroids
enter the Earth’s atmosphere each day

25. METEOROIDS
 While heated to incandescence by
atmospheric friction during their passage
through the atmosphere, they are
termed meteors.
 A fragment that survives to hit the ground
is known as a meteorite.

28. CLASSES OF METEORITES
 Chondrite
 Iron meteorite
 Carbonaceous chondrite

29. CLASSES OF METEORITES
 Chondrite
 Stony
meteorites

30. CLASSES OF METEORITES
 Iron
Meteorites
 Iron and
nickel

31. CLASSES OF METEORITES
 Carbonaceous
chondrites
 Organic
compounds

32. ANTARCTIC METEORITES
 Finds- discovered by
accident
 Falls- seen falling from the
sky

33. TWO TYPES OF METEORS
Sporadic
 orbital paths intersect that of Earth in
random directions
Meteor Shower
 the remains of old comets that have left lots
of small particles and dust in a common
orbit

34. METEORS
Meteor craters
 Barringer Meteor Crater in Northern
Arizona
 25, 000 years old
 4, 200 feet in diameter
 Depth of 6,000 feet