1. Physics 112 Star Systems Lecture 18 The Debris Kevin H Knuth
University at Albany
Fall 2013

2. Sol’s Planets

3. The Asteroid Belt
The Asteroids lie between the orbits of Mars and Jupiter.
An orbital resonance with Jupiter prevented a planet from forming there.
The result is a mass
of debris that we call
Asteroids.

4. Eros

5. Eros Movie

6. Ida and its moon Dactyl

7. Itokawa

8. Near Earth Asteriods Orbits of known near-Earth asteroids
About 1000 near-Earth asteroids are known, with sizes up to 30 km.
Tens of thousands probably exist with
the number of NEAs with sizes greater than
1 km numbering around 2000.
Objects ~20m in size create 20 MTon explosions. This happens about 8-10
times a year!!!

9. The Solar System and Oort Cloud

10. Comets

11. Halley’s Comet
Sir Edmund Halley was the first to realize that the comet observed by Petrus Apianus in 1531, the comet observed by Johannes Kepler in Prague in 1607 and the comet of 1682 were the same comet.
He predicted its return in 1757, but it was not observed until December 25, 1758.
Halley, having died in 1742 never saw the comet’s return.
French mathematicians computed that Jupiter and Saturn perturbed and delayed its return by 618 days.
Edmond Halley Born: November 8, 1656 Died: January 14, 1742

12. Halley’s Comet throughout History
Early Record of Halley’s Comet: Bayeux Tapestry 1066

13. Halley’s Comet throughout History
Canterbury, England in 1145
Giotto with Halley’s Comet as the Star of Bethlehem in 1301

14. Halley’s Comet throughout History
Chinese Records in 1378 were part of a series that convinced Halley that the Comet was on a periodic orbit.
Petrus Apianus in 1531 illustrates that the comet’s tail points away from
the Sun.

15. Halley’s Comet
If Halley’s comet was closest to the Sun in 1986 and will be farthest from the Sun in 2024, when will it be closest to the Sun again?

16. Halley’s Comet is a BIG Dirty Snowball
In this image taken by the European probe Giotto,
you can see the nucleus of Halley’s comet vaporizing
due to the heat from the Sun.
It is now about 15 km long and 8 km wide.

18. Earth Passes through the Orionids

19. Comet Tails
Comets have two tails. A dust tail and an ion tail. The ion tail is blown straight back by solar wind.
The dust tail is the debris that vaporizes off the comet.
ion tail
dust tail

20. Comet Swan

21. Comet McNaught