1. Why Water?

2. Extremophiles
Live in harsh conditions we used to think could not possible support life:

3. Extremophiles
– lining the rim of a pitch-black, deep sea volcanic vent

4. Extremophiles
– can living in steaming hot springs

5. Extremophiles
– or frozen in ice in an Antarctic lake.

6. Life can handle dark, hot, cold, and salty, but it absolutely must have…

7. Liquid Water…
…Is essential to life

8. Kangaroo Rat vs. Salmon
Have same % of water content in cells (50 – 65 %)
Same % of salt in cells
(about 1 % on average)
1/3 of salt in sea water
(about 3.5 % on average)

9. Frost Line

10. Habitable Zone
The region of the solar system where temperatures allow water to exist in its liquid state.

11. On Earth, water exists in three physical states:
Water Vapor (Gas)
Solid Water (Ice)
Liquid Water
On Earth, water exists in three physical states:

12. Venus-(800oF) - Too Hot!

13. Mars (-67oF) - Too Cold Mars Water is frozen.
Ice caps even have dry ice (frozen CO2).

14. Earth - The “Blue” Planet - “Just Right”
Earth lies right in the middle of our solar system’s habitable zone.

15. Only Earth has liquid water. (and it covers ¾ of it surface!!)

16. Liquid Water…
…Is essential to life

17. Possibilities for Space Colonies
Europa
Moon of Jupiter
Water is frozen into ice.
May have a thick zone of liquid water below the ice

18. Possibilities for Space Colonies
Europa
Moon of Jupiter
Water is frozen into ice.
May have a thick mantle zone of liquid water below the ice

19. Possibilities for Space Colonies
Titan
Moon of
Saturn
Only moon
with an atmosphere
Surface water is frozen
May have a thick mantle zone of liquid water and ammonia below the ice
Possibilities for Space Colonies

20. Habitable Zone of Another Solar System
The region of a solar system where temperatures allow water to exist in its liquid state. a
(Red Dwarf
0.3 M סּ)

21. Possibilities for Space Colonies

22. Ammonia – Another Polar Solvent
Ammonia (NH3) is a polar molecule just like water.
Ammonia has just one lone pair of electrons.
Water has much stronger H-bonds, so it is harder to vaporize and more likely to be a liquid at Earth temperatures (Oo C to 100o C)
AMMONIA

23. Ammonia – Another Polar Solvent
H-bonds between ammonia molecules are much weaker than the H-bonds between water molecules.
As a result, ammonia vaporizes to a gas much more easily.
AMMONIA

24. Ammonia – Another Polar Solvent
For a planet to have ammonia- based life forms, the temperature would need to be down around o C to -78o C!
Where does it get that cold?
Maybe on Titan??
AMMONIA

25. Possibilities for Space Colonies
Titan
May have a mixture of liquid water and ammonia in its mantle
has surface pools of liquid hydrocarbons (ethane & methane)