A Clarification

The Constellation program was for space exploration and lunar/planetary science. It was not going to be prospecting for

water!

(As we learned last week, that wouldn’t make sense.)

The cancellation of Constellation doesn’t affect humanity’s fresh water problems, but it means that for the first time in about 50 years, the U.S. will not have a government-run manned launch

vehicle.

We will be dependent upon other government agencies, and eventually private industry, to get astronauts to and from orbit.

The Moon

• The only celestial body people have walked on (other than Earth)

• The only celestial body for which we have radiometric ages (other than Earth and meteorites)

• The only celestial body for which we have seismic data (other than Earth)

• Only 1 geologist has been there

• We’ve only explored a tiny amount of the surface– 6 landings

– longest sortie <20 km

Lunar contributions to Planetary Science

• “Pristine surface”, in Earth’s neighborhood

• Absolute age determinations (Apollo and Soviet samples)

• Calibration for relative age dates used throughout the Solar System

• Heavy Bombardment

Dating

• Absolute– Radiometric age dating

– Compare (radioactive) parent & (radiogenic) daughter isotopes with non-radiogenic isotopes

– Look at different crystals, different isotopes, to get a good estimate

• Relative– Concept: older surface has had more time to be hit by

meteorites

– Complications: exhumation, “secondary craters”

Earth’s surface: types of rocks

Images from http://www.fas.org/irp/imint/docs/rst/Sect2/Sect2_1.html, http://www.learner.org/acourses/essential/earthspace/session3/closer1.html, http://www.americansouthwest.net/arizona/bill_williams_river/bwrocks_l.html

Surface Processes

• Erosion

• Tectonics

• Volcanism

• Impacts

Images from http://fireflyforest.net/firefly/2005/11/12/aerial-view-of-the-grand-canyon/, http://www.scientificamerican.com/article.cfm?id=geologists-link-the-great, http://rst.gsfc.nasa.gov/Sect18/Sect18_1.html, and http://users.forthnet.gr/ath/nikolas_c/tectonic_geoology.htm

The Moon’s surface

Images from http://www.lpi.usra.edu/lunar/missions/clementine/images/ and http://www.lpi.usra.edu/lunar/missions/apollo/apollo_17/experiments/lnp/

New lunar images

http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html

Earth’s interior

http://www.gly.uga.edu/railsback/1121CrMaLiAsthenosphere.jpeg

Earth’s interior, cont.

P wave S wave

http://geophysics.ou.edu/solid_earth/notes/seismology/seismo_interior/seismo_interior.html

The Moon’s interior

http://www.astro.psu.edu/users/niel/astro1/slideshows/class41/slides-41.html

Earth’s atmosphereGas Name Chemical Formula Percent Volume

Nitrogen N2 78.08%

Oxygen O2 20.95%

*Water H2O 0 to 4%

Argon Ar 0.93%

*Carbon Dioxide CO2 0.0360%

Neon Ne 0.0018%

Helium He 0.0005%

*Methane CH4 0.00017%

Hydrogen H2 0.00005%

*Nitrous Oxide N2O 0.00003%

*Ozone O3 0.000004% * variable gases

From http://www.physicalgeography.net/fundamentals/7a.html

The Greenhouse Effect

http://www.fas.org/irp/imint/docs/rst/Sect16/Sect16_2.html

http://geophysics.ou.edu/solid_earth/notes/seismology/seismo_interior/seismo_interior.html