1. Asteroids, Comets & Meteors…. Grab a Book and go learn about them!

3. Comparing A, C, M How does it form, origin Composition Size Orbit
Found / located where
How are they seen in the sky
Glow? Reflective? Burn?
Best known example
Asteroid
Comet
Meteor

4. The Solar System Leftovers
ALL are Leftovers from the formation of the Solar System 4.6 bya went into either the
Asteroid belt
Kuiper Belt
Oort Cloud
Cosmic “debris”
Range in size from mountain sized chunks to dust

5. The Asteroid Belt Between Mars an Jupiter
Astronomers have cataloged more than 500,000 asteroids
in near circular orbits. (eccentricity close to 0)
All orbit in counter-clockwise.
The tilt orbits - more exaggerated than the planets.

6. Asteroids Also classified by albedo
Too small to be classified as planets, (100 m – 100 km)
Gravitational pull of Jupiter and Mars
didn’t allow for material to form a planet.
About half the known asteroids are probably ‘dead’ comets
Also classified by albedo
How well their surface reflects sunlight and we can see them

7. Way out beyond Neptune
“outer asteroid belt”
Consists of mostly ICY, rocky objects
Very elliptical orbits

8. Large Asteroid or Dwarf Planet?
Ceres
950 km wide
(590 miles)
In 2006, Ceres was upgraded from an asteroid a ‘dwarf planet’
Pluto
2300 km wide
(1430 miles)
A the same time, Pluto was down-graded from a planet to a dwarf planet

9. Comets Greek for “long hair”
Called ‘dirty snowballs’ because of their composition
A mixture of ice, frozen gas, and dust
Material that didn’t get incorporated
into planets during
solar system formation

10. Comets, cont.
Most comets live in a cloud beyond Pluto called the Oort Cloud
1-10 km in size
Comets have HIGHLY elliptical orbits, - some comets take millions of years to complete one orbit.

11. Parts of a Comet

12. The comets ion tail is always pointed AWAY from the Sun
The comets ion tail is always pointed AWAY from the Sun. The dust tail curves and lags behind the ion tail. Comets can be seen for many days.

13. Meteors Bits of the solar system that have fallen to the Earth
Most come from asteroids
Some come from left-behind comet debris

14. Catch a Falling Star
Meteor is the term for the sight of the streak of light caused by a meteoroid –which is the term for the small (less than 100 m) rocky object that enters the atmosphere.
Most are completely burned up, but some do get through to strike Earth = meteorites

15. Meteor Showers (a.k.a. Comet showers)
Whenever a COMET makes its nearest approach to the Sun, some pieces break off.
The larger fragments take up orbits with the parent comet, but some fall behind, so that the comet’s path is eventually filled with the tiny micrometeoroids.

16. Meteor Showers
Periodically, Earth’s orbit intersects with a cluster of such micrometeoroids, resulting in a meteor shower.
Meteor showers associated with certain comets occur with high regularity.
They are named after the constellation from which their streaks appear to radiate.

17. Name of the Meteor Shower
Max. Activity
Est. Hourly Count
Parent Comet
Quadrantid
Jan. 3 50
Unknown
Beta Taurid
June 30 25
Encke
Perseid
Aug. 12
50+
1862III
Draconid
Oct. 8-9
500+
Giacobini-Zimmer
Orionid
Oct. 20
Halley
Leonid
Nov
10*
1866I
Geminid
Dec
50-75
3200 Phaeton

18. Asteroids, meteor composition.
Three types:
Carbon, Silica (rocky), Metallic (iron and nickel)
- Carbon meteorites contain water and organic molecules, amino acids – the building blocks of life!

19. Scientists believe that the water in the earths hydrosphere arrived here in icy meteorites over millions of years of bombardment

20. Why do scientists study meteorites??
Most meteorites are similar to rocks on Earth,
But a few have rare minerals only found in meteorites.
Meteorites represent many different rock types and probably come from different bodies in the solar system.
They are the oldest rocks in the solar system and are used to date the beginning of the solar system.
The early solar system had very different composition, temperatures and pressures
Scientists study meteorites b/c they can tell us about the composition of our planet since they formed at the same time from the same material.

21. Could it Happen?
Nearly 100 asteroids have been identified to have eccentric orbits that cross that of Earth.
The possibility of a collision is real.
Project NEAT (Near Earth Asteroid Tracking)

22. Asteroids, Comets, Meteoroids
As many as 1000 NEO’s may be large enough to threaten the Earth should an impact occur.

23. What killed the dinosaurs?
An asteroid, a meteor or a comet?

24. Bellwork: matching a. asteroid b. meteoroid c. comet
1. Rank from smallest to largest.
2. Which are located in the:
asteroid belt, Oort Cloud
3. Which “glow” with burning gases?
4. Which are rocky?
5. Very elliptical and tilted orbit?
M C A
Asteroids comets
M C
A M
comets