A satellite image is composed of multiple "bands" which are essentially simultaneously acquired images of the same exact area but in different wavelength ranges. Each band of an image shows different features, in the images below the golf courses are most prominent.

Bands 1 (blue), 2 (green), 3 (red), 4 (near IR) and 5 (mid IR) and 7(far IR)

Bands 6 (pan-sharpened thermal/panchromatic)

Band Composite Images
-  band 3-2-1 combinations are refereed to as "natural color" because the use visible wavelengths (red, blue and green respectively)
 - green grass is bright red on the band 4-3-2 composite image.
 - band 7-4-2 combination makes all sorts of things stand out!

Bands 3 2 1, Bands 4 3 2 and Bands 7 4 2

Sources: http://landsat.gsfc.nasa.gov/data/Browse/Comparisons/L7_BandComparison.html, http://ceos.cnes.fr:8100/cdrom-00b2/ceos1/datapic/landsat/band/band.htm

ASTER False Color Composite (Palm Springs)

Landsat 7 Image of the Keenaw Peninsula (Michigan)

Landsat 7 Image of the Santa Barbara California (April 15, 1999)

Bands 1 (blue), Bands 2 (green), Bands 3 (red), Bands 4 (near IR), Bands 5 (mid IR), Bands 6 (thermal IR) and Bands 7(far IR)

Composite Images Bands 321, Bands 432 and Bands 742 (see Additive Color)

Yosemite Fire
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Band        Spectral Range(microns)         Resolution(m)
1                    0.45 to 0.515                            30
2                   0.525 to 0.605                           30
3                    0.63 to 0.690                            30
4                     0.75 to 0.90                            30
5                    1.55 to 1.75                             30
6                   10.40 to 12.5                            60  (*thermal, low emitted energy = bigger pixels!)
7                    2.09 to 2.35                             30
Pan                  0.52 to 0.90                            15

Swath width: 185 kilometers
Repeat coverage interval: 16 days (233 orbits)
Altitude: 705 kilometers
On-board data storage: ~375 Gb (solid state)
Inclination: Sun-synchronous, 98.2 degrees
Equatorial crossing: 10:00am +/- 15 min.
Launch vehicle: Delta II
Launch date: April 1999
 

-  band 4 (0.75 - 0.90 microns) is used in composites due to the strong differentiation of reflectance from vegetation

Gallery of Landsat 5 TM 543 Composites
Other Material (lecture graphics)
Lab Material (assignment, images and graphics)
MA Thesis "On the Value of Coordinating Landsat Operations"