The Search for Life in the Solar System

1
The Search for Life in the Solar System

• HNRS 228 w/Geller
• Reviewing Chapter 6

2
Whats Up

• Review Requirements for Life
• Elements, Energy, Water, etc.
• Searching for Life in Our Solar System
• Remote Sensing, Robotics, Human Exploration, etc.
• Biological Tour of the Solar System
• Terrestrial Planets, Jovian Planets, other bodies

3
Environment for Life?

• Source of elements to build cells
• Source of energy
• Medium for transporting molecules

4
H2O and CO2 Phase Diagrams (IMPORTANT
environmental consideration)
5
Exploring the Solar System

• Observations from Earth
• ground or orbit based
• Robotic spacecraft
• flybys, orbitals
• landers
• Human exploration

6
Planet Generalization

• Terrestrial planets are closer to sun
• Mercury
• Venus
• Earth
• Mars
• Jovian planets furthest from sun
• Jupiter
• Saturn
• Uranus
• Neptune

7
Planetary Summary
8
Some Conclusions

• Planets formed at same time as sun
• Planetary and satellite/ring systems are similar
  to remnants of dusty disks such as that seen
  about stars being born (e.g. T Tauri stars)
• Planet composition dependent upon where it formed
  in solar system

9
Nebular Condensation Model

• Most remnant heat from collapse retained near
  center
• After sun ignites, remaining dust reaches an
  equilibrium temperature
• Different densities of the planets are explained
  by condensation temperatures
• Nebular dust temperature increases to center of
  nebula

10
Nebular Condensation Physics

• Energy absorbed per unit area from sun energy
  emitted as thermal radiator
• Solar Flux Lum (Sun) / 4 x distance2
• Flux emitted constant x T4 Stefan-Boltzmann
• Concluding from above yields
• T constant / distance0.5

11
Nebular Condensation Chemistry
12
Nebular Condensation Summary

• Solid Particles collide, stick together, sink
  toward center
• Terrestrials -gt rocky
• Jovians -gt rocky core ices light gases
• Coolest, most massive collect H and He
• More collisions -gt heating and differentiating of
  interior
• Remnants flushed by solar wind
• Evolution of atmospheres

13
Biological Tour of the Solar System

• Consider problems posed for life on each of the
  following
• Moon
• Mercury
• Venus
• (Mars will be discussed in Chapter 7)
• Jovian Planets
• Other Moons
• Asteroid, comets and other debris

14
Some References

• The Search for Life (especially in the solar
  system)
• http//www.scibridge.sdsu.edu/coursemats/introsci/
  Solarsys/lecture.html
• http//www.resa.net/nasa/ocean_hydrothermal.htm
• http//www.nationalacademies.org/ssb/lifeoriginsme
  nu.htm
• http//www.phy.syr.edu/courses/modules/SETI/where.
  html
• Books
• Life on Other Worlds (Dick)
• Cradle of Life (Schopf)
• Life Everywhere (Darling)
• Life on Other Worlds and How to Find It (Clark)