(Image by Robert Simmon, NASA GSFC, based on Landsat Thematic Mapper data archived by the )

(Image by the based on data from NOAA.)

(Image by the based on data from NOAA.)

(Image courtesy )

(Image courtesy based on data copyright Space Imaging)

(Image courtesy Jacques Descloitres, MODIS Land Group, NASA Goddard Space Flight Center)

(Image courtesy Jacques Descloitres, MODIS Land Group, NASA GSFC)

(Images courtesy the , and the

(Images courtesy the National Center for Ecological Analysis and Synthesis, and the Department of Geography at the University of Oregon)

(Maps courtesy Curtis Marshall, Colorado State University/NOAA)

(NASA Image by Robert Simmon, based on Landsat data provided by the UMD )

(NASA Image by Robert Simmon, based on Landsat data provided by the UMD )

* Credit for Lick Observatory Image:* W. Li and A. V. Filippenko (University of California, Berkeley) * Credit for HST Image:* NASA [ http://www.nasa.gov/ ], ESA [ http://www.spacetelescope.org/ ], The Hubble Heritage [ http://heritage.stsci.edu/ ] Team (STScI [ http://www.stsci.edu/ ]/AURA [ http://www.aura-astronomy.org/ ]), and A. Riess (STScI [ http://www.stsci.edu/ ])

* Illustration courtesy of:* Bill Pounds

* Illustration:*: NASA [ http://www.nasa.gov/ ] and K. Cordes (STScI [ http://www.stsci.edu/ ])

* Illustration:*: NASA [ http://www.nasa.gov/ ] and K. Cordes (STScI [ http://www.stsci.edu/ ])