Where can we find water?

Importance of water to life

• Water to drink; we need to stay hydrated to remain alive; we are 55 – 75% water!

• Solar energy converted by plants; water is the catalyst that helps plants grow.

• Water vapor in the atmosphere traps radiation and warms up the Earth.

• Earth’s oceans affect climate and store heat.

H2O NH3 CH4 Water, Ammonia, Methane

CO2 CO N2

Ignore inert gasesHe, Ne, Ar

The Cosmic Abundance of ElementsThe Cosmic Abundance of Elements

Water phase diagram

Can there be ice on the Moon?

• Comets and asteroids could have left water on the Moon – just like on Earth?

• Effects of temperature and pressure implies water sublimates in sunlight and drifts off into space.

• Moon has deep cold craters where sunlight cannot reach!– Water may exist in such places as frozen

ice

There are many craters near the poles that are permanently shadowed

South Pole North Pole

What is the evidence for ice on the Moon?

• Lunar Prospector shows enhancement of H, indicating possible presence of ice

Water in the solar system - Mars• Indications that water once flowed on the surface.• Much of the water may exist as subsurface ice.

Water in the solar system - Comets

• Detected in comet’s tails.

• Up to 80% can be water ice.

Comet BorrellyDeep Space 1

Comet Wild 2Stardust

Deep Impact-July 2006

Then there’s Ceres…

• Ceres (largest asteroid) discovered in 1801.

• Average density of the asteroids ~5g/ml

• Ceres density ~2.1 g/ml

• Comets avg. density ~1,5-2.0 g/ml

• Dawn mission on the way to Ceres (2011)

Ceres, as imaged by Dawn 1/14/15

The Top Four Icy Moons

Europa Triton Enceladus Titan

Most icy satellites are smaller than our moon. What surface features should we see on them?

Europa Triton Enceladus Titan

Jupiter Neptune Saturn

Huygens images of Titan’s surface

Methane lakes on Titan

A water-ammonia volcano on Titan through 3 wavelengths

L-Infrared, C-Radar, R-Ultraviolet

Fountains of Enceladus

Enceladus

enceladus sounds.mov

Neptune’s moon Triton-a Plutonian twin?

Triton and Pluto at Best HST Resolution

Triton from Voyager

Importance of water in human space exploration

• Water to drink.Water to grow plants.• Water can be broken apart to make air

(oxygen) and rocket fuel (oxygen + hydrogen)• Water can be used to provide electrical power• (fuel cells used by Gemini, Apollo, and ISS).• Water for protection.• Water is heavy, too expensive to carry.