# Planetary Data Facts

## The Largest

The following 17 sun, planets and satellites are greater than 1,100 kilometers in radius. Although Uranus is slightly larger than Neptune, the density of Neptune is greater resulting in a greater mass for Neptune. The same holds true for Mercury which is denser that Ganymede and Titan.

                        Distance   Radius  Mass
    Name       Orbits   (10^3 km)   (km)   (kg)
    ------------------------------------------------
    Sun        -               -  695,000  1.989e+30
    Jupiter    Sun       778,330   71,492  1.9e+27
    Saturn     Sun     1,429,400   60,268  5.688e+26
    Uranus     Sun     2,870,990   25,559  8.686e+25
    Neptune    Sun     4,504,300   24,746  1.024e+26
    Earth      Sun       149,600    6,378  5.976e+24
    Venus      Sun       108,200    6,052  4.869e+24
    Mars       Sun       227,940    3,397  6.421e+23
    Ganymede   Jupiter     1,070    2,631  1.48e+23
    Titan      Saturn      1,222    2,575  1.35e+23
    Mercury    Sun        57,910    2,440  3.303e+23
    Callisto   Jupiter     1,883    2,400  1.08e+23
    Io         Jupiter       422    1,815  8.94e+22
    Moon       Earth         384    1,737  7.349e+22
    Europa     Jupiter       671    1,569  4.8e+22
    Triton     Neptune       355    1,350  2.14e+22
    Pluto      Sun     5,913,520    1,160  1.29e+22

## The Smallest

The following 16 satellites are smaller than 20 kilometers in maximum radius. Many asteroids and comets are smaller than these bodies, but some are larger.

                        Distance  Radius         Mass
    Name       Orbits   (10^3 km)  (km)          (kg)
    -------------------------------------------------------
    Deimos     Mars        23.46   7.5x6.1x5.5   1.8e+15
    Leda       Jupiter    11,094   8             5.68e+15
    Pan        Saturn    133.583   9.7           ?
    Adrastea   Jupiter   128.971  12.5x10x7.5    1.91e+16
    Cordelia   Uranus     49.750  13             ?
    Phobos     Mars        9.380  13.5x10.8x9.4  1.08e+16
    Ananke     Jupiter    21,200  15             3.82e+16
    Ophelia    Uranus      53.76  16             ?
    Calypso    Saturn     294.66  17x11x11       ?
    Telesto    Saturn     294.66  17x14x13       ?
    Sinope     Jupiter    23,700  18             7.77e+16
    Lysithea   Jupiter    11,720  18             7.77e+16
    Helene     Saturn     377.40  18x16x15       ?
    Atlas      Saturn     137.64  20x15          ?
    Metis      Jupiter   127.969  20             9.56e+16
    Carme      Jupiter    22,600  20             9.56e+16

## The Brightest

The brightness of a body is determined its albedo, size, and distance from Earth. Vo is the apparent magnitude of the maximum brightness of an object in visible light. The following lists 12 bodies that can be seen by the naked eye or with binoculars.

                               Radius
    Name       Orbits   Vo      (km)     Albedo
    -------------------------------------------
    Sun        -       -26.8   695,000   -
    Moon       Earth   -12.74    1,737   0.12
    Venus      Sun      -4.4     6,052   0.65
    Jupiter    Sun      -2.70   71,492   0.52
    Mars       Sun      -2.01    3,397   0.15
    Mercury    Sun      -1.9     2,440   0.10
    Saturn     Sun       0.67   60,268   0.47
    Ganymede   Jupiter   4.61    2,631   0.42
    Io         Jupiter   5.02    1,815   0.61
    Europa     Jupiter   5.29    1,569   0.64
    Uranus     Sun       5.52   25,559   0.51
    Callisto   Jupiter   5.65    2,400   0.20

From time to time, a comet will pass close enough to the Sun to develope a coma that becomes visible to the naked eye.

## The Dimmest

The following are the dimmest known satellites in our solar system. Their apparent magnitudes are greater than 20. A magnitude of about 19.5 is the limit for a visual observation of an object using one of the largest telescopes.

                              Radius
    Name       Orbits    Vo    (km)   Albedo
    ----------------------------------------
    Naiad      Neptune  24.7   29     0.06
    Cordelia   Uranus   24.1   13     0.07
    Ophelia    Uranus   23.8   16     0.07
    Thalassa   Neptune  23.8   40     0.06
    Bianca     Uranus   23.0   22     0.07
    Despina    Neptune  22.6   74     0.06
    Desdemona  Uranus   22.5   29     0.07
    Rosalind   Uranus   22.5   27     0.07
    Galatea    Neptune  22.3   79     0.06
    Cressida   Uranus   22.2   33     0.07
    Belinda    Uranus   22.1   34     0.07
    Larissa    Neptune  22.0  104x89  0.06
    Juliet     Uranus   21.5   42     0.07
    Portia     Uranus   21.0   55     0.07
    Proteus    Neptune  20.3  200     0.06
    Puck       Uranus   20.2   77     0.07
    Leda       Jupiter  20.2    8      ?

## The Densest

The following table lists 11 of the most dense planets and satellites in the solar system.

                       Radius     Mass       Density
    Name       Orbits   (km)      (kg)       (g/cm^3)
    -------------------------------------------------
    Earth      Sun     6,378      5.976e+24  5.515
    Mercury    Sun     2,440      3.303e+23  5.42
    Venus      Sun     6,052      4.869e+24  5.25
    Adrastea   Jupiter    13x10x8 1.91e+16   4.5
    Mars       Sun     3,397      6.421e+23  3.94
    Io         Jupiter 1,815      8.94e+22   3.55
    Moon       Earth   1,737      7.349e+22  3.34
    Elara      Jupiter    38      7.77e+17   3.3
    Sinope     Jupiter    18      7.77e+16   3.1
    Lysithea   Jupiter    18      7.77e+16   3.1
    Europa     Jupiter 1,569      4.8e+22    3.01

## The Most Eccentric

The following table lists the 7 most eccentric planets and satellites in the solar system.

                        Distance  Radius
    Name       Orbits     (km)     (km)   Eccentricity
    ------------------------------------------------
    Nereid     Neptune  5,513.40    170   0.7512
    Pasiphae   Jupiter    23,500     25   0.378
    Sinope     Jupiter    23,700     18   0.275
    Pluto      Sun     5,913,520  1,160   0.2482
    Elara      Jupiter    11,737     38   0.2072
    Carme      Jupiter    22,600     20   0.2068
    Mercury    Sun        57,910  2,439   0.2056

## The Most Reflective

    -------------------------------------------------------
    Name       Orbits  Vo         Distance Density    Albd
    -------------------------------------------------------
    Enceladus  Saturn  11.7         238.02 1.24       0.99
    Pandora    Saturn  16.5         141.70 0.7*       0.9
    Atlas      Saturn  18.0         137.64 ?          0.9
    Tethys     Saturn  10.2         294.66 1.21       0.9
    Janus      Saturn  14.5        151.472 0.67*      0.8
    Epimetheus Saturn  15.7        151.422 0.7*       0.8
    Dione      Saturn  10.4          377.4 1.43       0.7
    Rhea       Saturn  9.7          527.04 1.33       0.7
    Helene     Saturn  18.5         377.40 ?          0.7
    Triton     Neptune 13.47        354.80 2.07       0.7