1. Small Bodies in the Solar System
Comets
Asteroids
Meteorites

2. What is a Comet? A comet is a small body of ice, rock and cosmic dust
Sometimes referred to as dirty snowballs
The tail of a comet occurs when solar radiation heats the ice and gas is given off
What is a Comet?

3. The orbits of comets are very elongated elliptical shapes.
When a comet approaches the sun its tail can extend millions of kilometers into space
Comets often have two tails- The ion tail, which always points away from the sun (because of solar wind) and the dust tail which can point either way
What is a Comet?

5. Solar Wind pushes tail away from the sun

6. Origin of comets Scientists believe comets come from two places…
from the Oort cloud, which is a region that surrounds the solar system
Also from the Kuiper belt, which is outside the orbit of Neptune

7. Origins Oort Cloud Kuiper Belt

9. Large rocky bodies (objects) that orbit the sun, usually found between the orbits of Mars and Jupiter. This region is called the asteroid belt.
What are Asteroids?

11. Types of Asteroids Asteroids come in many interesting shapes and sizes
Composition of asteroids varies usually by where they are found
In the outermost region asteroids appear to be rich in organic material with reddish brown to black surfaces

12. Asteroids cont…
The inner most part of the asteroid belt consists of light gray asteroids with either a stony or metallic composition

13. Asteroid Belt and Meteors
Mars

14. Some 65 million years ago, a 10 to 12 km in size asteroid or
comet crashed on the Yucatan platform and formed the
200 km in diameter Chicxulub crater. Huge volumes of rocks
were excavated, molten and vaporized in the atmosphere in
matter of minute, altering the climate and triggering
darkness and climatic cooling as during an nuclear winter.
See craters far from earth

16. belts

18. When was the last asteroid strike
When was the last asteroid strike? The last large asteroid strike was in 1908 in Siberia when a 60 meter stony body exploded in the atmosphere causing a blast that knocked over trees in an 800 mile squared area from the blast centre. Small asteroid fragments were found embedded in trees around the blast site.

19. Artist’s depiction

23. What are Meteoroids? A small rocky bodies that revolves around the sun
Much smaller than asteroids, most likely they are pieces of asteroids
What are Meteoroids?

24. Scientific names for meteoroids to identify…
A meteorite is a meteoroid that enters Earth’s atmosphere and strikes the ground
A meteor is the bright streak of light you see, sometimes called a shooting star
Meteor showers are large numbers of small meteors usually caused by Earth passing by dusty debris left by a comet
Scientific names for meteoroids to identify…

25. Types of Meteorites Three major types: Stony Metallic
Stony iron- may contain organic materials and water

26. Crater in Arizona

31. Impacts and the Torino Scale
Earth is protected by its atmosphere- some planets and moons with no atmosphere have many impact craters
Craters on Earth are also weathered and eroded
Impacts causing natural disasters are infrequent and global impacts occur about every 300,000 years.

32. What is the Torino Scale?
The Torino scale is a system allowing scientists to rate hazard level of an object moving toward Earth
What is the
Torino
Scale?