1. Other Solar System Objects

2. A Review of The Nebular Theory
Begins to pull together (gravity) about 4.6 BYA
Nebula
Protostar
X-ray and infrared photos of protostar
Accrete, solar wind blows away H, He
Protoplanets
Solar System with 8 planets

3. In addition to planets, our solar system contains…
Moons
Natural satellite of a planet
Vary in size
Vary in number
Size – some are bigger than Earth
Pluto’s moon – Charon, is almost as big
Some planets have none – Mercury & Venus
Jupiter has 63 (at last count!)

4. Ring Systems
Collection of dust particles and rocks that orbit a planet
Found around all Jovian planets

5. Comets
A space object made of rocks and frozen gasses – a “dirty snowball”
originate in the Oort Cloud

6. Comets Some have a regular orbit – short or long period
en.wikipedia.org/wiki/153P/Ikeya-Zhang
Halley’s Comet has a period of 76 years
Came “in” and “out” with Mark Twain
Last came in 1986, next visit in 2062

7. Head / nucleus – rock and frozen gas
Head / nucleus – rock and frozen gas
Tail (coma) melted gases – “split” – ion tail and dust tail
Always points away from sun
www4.nau.edu/.../Meteorite/Book-GlossaryC.html

8. Note “split tail” www.nasaimages.org/luna/servlet/detail/NVA2~1...
museumvictoria.com.au/.../planets/comets/
Note “split tail”

9. Asteroid A space object made of rocks and metals Size can vary
Occur in asteroid belt
Gaspra
Size varies from pebble to “state”
Occur in asteroid belt, between Mars and Jupiter
Eros

10.
Meteor – a streak of light one sees when a space object (usually a small asteroid) burns up in Earth’s atmosphere (because of… friction)

11. Wales – October 2003 Sofa-sized rock/fireball

12. Persiades – Aug 12 Orionides – Oct 16 – 21 Geminides – Dec 7 - 15
Meteor Shower – period ( a few hours or nights) with a large number of meteors
Persiades – Aug 12
Orionides – Oct 16 – 21
Geminides – Dec

13. Meteorite
A piece of the object that hit our atmosphere and lands on Earth
Up to 200 a day (most are “specks”)
Left – from Arizona crater
Right – largest known – 50 tons (Russia?)

14. Meteoric Bombardment Why is there so little evidence on Earth?
The Moon has blocked a lot of shots
Atmosphere – objects burn up, weather and erosion
Many craters are under water or under plants
Plate tectonics

15. Even So… Barringer Crater, AZ Labrador, Canada Sahara Desert
Barringer Crater – 50,000 years ago – 130 ft wide asteroid - crater is 1 mile across
Also Aral Sea, Hudson Bay
Labrador, Canada
Sahara Desert

16. Even So… Chicxulub Crater - 65 million years ago, 10 to 20km across
2004MN4 – “Apophysis” –pass by in 2029; gravity could set up a future impact on April 13, 2036
Chicxulub Crater – Yucatan Peninsula – 65 MYA – comet nucleus 6 miles wide – crater 100 miles across
water / dust in atmosphere blocked sunlight for 6 years – mass extinction, including most dinosaurs
2004MN4 – 640 mile wide asteroid – near miss on April 13, 2029 (Fri! )
will pass within 30,000 km (closer than geosynchronous satellites)
return trip – April 13, 2036 – could be a direct hit !!!!
Sahara Desert