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)
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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
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Name Orbits Vo Distance Density Albd
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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