Life in our solar system? Definite locations The earth Possible locations Mars Europa
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
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
Atmospheric changes in a closed box- 1 Samples of moon rock atmosphere
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
Martian meteorites 1. A lump of rock from space that landed on earth was believed to be from Mars. 2. It was examined
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!
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.
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
SETI The Search for Extra Terrestial Intelligence
The Drake equation There are 10 000 alien races in the milky way galaxy Based upon large assumptions
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
Signals from space - 1 Regular Actually emitted by a pulsar – a rotating star
Signals from space - 1 Irregular 314 sent out by eti