Post on 26-Mar-2015
transcript
Life in the universe
The questions are
Is there life elsewhere in our solar system?
Is there life outside our solar system?
Ingredients for life
1. Liquid water
2. Atoms of C, O, H, N
3. Energy
The earth contains these ingredients
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
Basic life
1. Amino acids form
2. These join to make proteins and DNA
3. DNA can reproduce itself
4. Bacteria form
Life?
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 wavesB. To collect samples – and the craft
must return to earthC. 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 for1. 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.
Life outside the solar system
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 waves2. They can pass through the gas and
dust clouds in space3. They can be collected by radio
telescopes4. 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
Read P212/213