A Clarification
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Transcript of A Clarification
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