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Life in the Universe - Astrobiology

Dr. R. L. Hudson (Spring, 2018)

Astrobiology and the Outer Solar System

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62

14

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April, 2018

172 Moons!

Mercury

Moon

Venus Earth Mars

TitanCallistoGanymedeEuropaIo

Jupiter

Jupiter from CassiniSpacecraft in 2000

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Galileo Galilei

1564 - 1642

Hubble Space Telescope (1990 - ?)

Voyager Spacecraft (1977 - ?)

Galileo Spacecraft

Launched 1989

Orbited 1995 - 2003

3

Io - from the Galileo Mission

Io has been mapped.

Io has active volcanoes!

Io has active volcanoes! Europa

Voyager Mission Galileo Mission

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Europa Surface Ice Europa Surface Ice

Europa and Superposition Europa Ice Rafts

Europa Surface Ice

Double-ridged pattern

Evidence for a Sub-surface Ocean

1. Fresh Surface

2. Ice Rafts

3. Tidal Heating

4. Magnetic Field

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Radiation from Jupiter - Drives Chemistry

For Astrobiology, Europa Has ...

1. Source of Energy

2. Matter (organics?)

3. Water

Future EuropaExploration

Europa Jupiter System Mission

2020

A Europa Submarine?

Ice Worms

Disc. 1997,Gulf of Mexico,

lives off CH4 hydrate

at lowtemperatures

Voyager Galileo

Ganymede

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Ganymede

Surface Ice

Callisto

Surface Ice

The Saturnian Family

Saturn and Titan

Saturn and Titan

Enlargement

Titan Atmosphere 95% N2 + 5% CH4

+ “Trace” Materials (ppm, ppb)

Possible Chemical Triggers Include ...

Solar UVSaturn’s Radiation Belts

Cosmic RaysLightning (?)

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O3 CH4-N2 Clouds/Rain

Hydrocarbon Haze

UV Photochemistry

Alti

tude

(km

)

Pre

ssur

e (m

bar)

Temperature (K)

p+

Some Detections

hydrocarbons and nitriles (cyanides)

C2H2 C2H4 C2H6 C3H8

HCN CH3CN HCC-CN NC-CN

NC-CC-CN as a solid

Saturn Up Close And Personal

Cassini-Huygens Mission1997 to 2004 to 2017?

Saturn from Cassini

2-9-2004 and 43 million miles from Saturn

Probe Release - December 25, 2004

Probe’s Soft Landing - January 14, 2005

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186 miles long

Titan Photos – Old & New Smooth Dark Material Suggests Lakes

(Paris, France)

Surface H2O Ice

Changes the

Chemistry

Astrobiology on Titan?

Cyanates (OCN-)

HC C CN

N

N

NH2

O

H

H

H

Organic Nitriles

p+H2O

cytosine

Titan

Enceladus

Sources of Material

Most of the images used here are either original, from our class’s textbook, or in the public domain. Material not fitting into these categories has been credited in cases where I knew the sources. I will be glad to add any credits missed.