1. Life in the universe The questions are Is there life elsewhere in our solar system? Is there life outside our solar system?

2. Ingredients for life 1. Liquid water 2. Atoms of C, O, H, N 3. Energy The earth contains these ingredients

3. Recipe for life 1. The seas of the early earth – often called the primordial soup contain the atoms 2. The Energy may come from lightning, hot underwater springs and the sun

4. Basic life 1. Amino acids form 2. These join to make proteins and DNA 3. DNA can reproduce itself 4. Bacteria form

5. Life?

6. Life in our solar system? Definite locations The earth Possible locations Mars Europa

7. Collecting evidence Send a spacecraft A. To take pictures of the surface – transmit back using radio waves B. To collect samples – and the craft must return to earth C. To examine the samples of atmosphere – can be done and results sent back using radio waves Only realistic in our solar system

8. What to look for 1. Photos of organisms alive or dead or their effects 2. Fossils in rocks – including fossilised bacteria 3. What the atmosphere is composed of 4. Changes to the atmosphere in a closed box

9. Atmospheric changes in a closed box- 1 Samples of moon rock atmosphere

10. Atmospheric changes -2 1. If the amount of O goes up 2. If the amount of CO2 goes down 3. Then there is probably simple life in the rocks

11. Martian meteorites 1. A lump of rock from space that landed on earth was believed to be from Mars. 2. It was examined

12. Life on mars? 1. Fossilised bacteria were found in the rock 2. These bacteria were smaller than any found on earth Some experts are not convinced!

13. Life on Europa? 1. Surface temperature –170C – too cold for life 2. Europa is covered with ice but it may be liquid beneath the surface. OK for life. 3. A robot probe will be sent by NASA in 2008 - this will drill into the ice-cap.

14. Life outside the solar system

15. Distances and times Mars 100 000 000 km 2 or years by spacecraft Nearest star other than sun 200 000 years by spacecraft 4 years at the speed of light

16. SETI The Search for Extra Terrestial Intelligence

17. The Drake equation There are 10 000 alien races in the milky way galaxy Based upon large assumptions

18. Listening for signals 1. Microwaves are short radio waves 2. They can pass through the gas and dust clouds in space 3. They can be collected by radio telescopes 4. Hundreds of amateurs have dishes connected to PCs these collect and display microwave signals

19. Signals from space - 1 Regular Actually emitted by a pulsar – a rotating star

20. Signals from space - 1 Irregular 314 sent out by eti

21. Read P212/213