Star groups 88 recognized Stars names by brightness in them Orion: Greek Hunter White Tiger: Chinese http://borghetto.astrofili.org/costellazioni/costellazioni.htm Bright star to lower left of Orion is Sirius http://www.windows.ucar.edu/the_universe/images/starmaps/map_orion.jpg http://lithops.as.arizona.edu/~jill/epo/posters/orion/protoplanets.html The Dog Star Brightest star in sky In Canis Major http://www.windows.ucar.edu/cgi-bin/tour_def/the_universe/images/starmaps/map_canis_major_jpg_image.html Second brightest in northern sky Very large Rather cool http://en.wikipedia.org/wiki/arcturus http://www.windows.ucar.edu/cgi-bin/tour_def/the_universe/arcturus.html 1
Revolution (orbit) around Sun Rotation on axis Proposed by Copernicus: prediction that other planets would have phases like Moon Galileo found phases of Venus with telescope obse at o s observations Tested with pendulum swing over a 24-hour day, by Foucault, in 1851 Precession of axial direction http://video.google.com/videoplay?docid=4242610371139275474&q=precession+of+equinox&total=54&start=10&num=10&so=0&type=search&plindex=4 Animation link -- http://www.astro.virginia.edu/class/oconnell/astr121/im/lunation-anim.gif http://www.astro.virginia.edu/class/oconnell/astr130/im/moon_sidereal.gif Takes 29 ½ days to proceed through its phases Synodic month Same side always faces Earth days Rotates on axis once each 27 1/3 days Sidereal month No atmosphere extreme temperature variation: 127o to -173o C Lunar eclipse Moon is in Earth s shadow Sidereal with reference to a distant star Note directions of view are parallel for sidereal month Solar eclipse Earth is in Moon s shadow Favorable for eclipse twice each year because Moon s orbital plane around Earth at an angle to Earth s orbital plane around Sun 2
3475 km diameter Density ~ Earth s mantle http://www.astrosurf.com/cidadao/moon_99_03_01.jpg More craters indicated older surfaces No weathering and erosion like on Earth Terra pale colored highlands Maria dark colored lowlands anorthosite basalt Impact of large object melted nearsurface material Flowed and solidified as the Maria we see 3
Some competing hypotheses: astronomycast.co t t m discovery.com Right part of photo is dark side that cannot be seen from Earth Distances not to scale Earth approximately 12,800 km diameter Earth is about 150,000,000,, km from Sun http://spacekids.hq.nasa.gov/osskids/animate/moon.html 4
Rocky material Ammonia, methane, carbon dioxide, water Predominantly hydrogen and helium Mostly silica and metallic compounds Very little amount of gases and ices Jovian p planets like Jupiter p Gases Terrestrial planets Ices note the s Silicate minerals Metal compounds mostly iron Lots of gases and ices Substantial amounts of rocky material in their core silica and metal http://cnr2.kent.edu/~manley/copernicus_crater_area.jpg 1973 launch Venus and Mercury in 1974 http://seds.lpl.arizona.edu/nineplanets/nineplanets/mercury.html http://www.solarviews.com/raw/venus/venusvis.gif http://pds.jpl.nasa.gov/planets/captions/mar10/m1004.htm Ultraviolet light photograph http://seds.lpl.arizona.edu/nineplanets/nineplanets/gif/venus.jpg Magellan radar image mosaic False color Magellan mosaic http://www.solarviews.com/browse/venus/venus1.jpg 5
Photo by Hubble http://hubblesite.org/newscenter/newsdesk/archive/releases/1995/16/image/b http://nssdc.gsfc.nasa.gov/image/planetary/venus/venera9-10.jpg http://pds.jpl.nasa.gov/planets/captions/mars/marssp.htm 461 km diameter CO2 frost at lower right Mosaic from Viking Mosaic by Mars Global Surveyor MOC http://pds.jpl.nasa.gov/planets/captions/mars/global.htm http://pds.jpl.nasa.gov/planets/captions/mars/schiap.htm http://pds.jpl.nasa.gov/planets/captions/mars/valmar.htm 624 km diameter 25 km k high h h http://pds.jpl.nasa.gov/planets/captions/mars/olympus.htm http://pds.jpl.nasa.gov/planets/captions/mars/valmar.htm http://www.solarviews.com/raw/mars/network.gif 6
http://pds.jpl.nasa.gov/planets/captions/mars/water.htm http://pds.jpl.nasa.gov/planets/captions/mars/vlfmos21.htm http://pds.jpl.nasa.gov/planets/captions/mars/vlpan22.htm Deimos http://pds.jpl.nasa.gov/planets/captions/mars/phobos.htm 7