Comets
This talk covers all sorts of odds and ends about comets. Areas covered include:
| What are comets? | Dirty snowballs; albedo; nucleus; tails |
| Where do they originate? | Formation of solar system; Oort cloud |
| Where are they now? | Kuiper belt; scattered disc; Oort cloud; Centaurs |
| What we see | Types of orbit; short-period; long-period; main belt |
| A bit of history | Myths and legends, mostly of woe; Europe; China; Aristotle |
| Water on Earth | Comets vs. asteroids; isotopic ratios of hydrogen and deuterium |
| Panspermia | Can comets be vectors; Wickramasinghe/Hoyle theories |
| Collision with Earth | Energy yields; Chicxulub; Tunguska; Ways to divert a comet; invisible very low albedo ex-comets |