Appendix 2: Solar System Extrema
Appendix 2: Solar System Extrema
There are 17 bodies in the solar system whose radius is greater
than 1000 km.
![[big worlds]](gif/soletal.gif)
This composite shows the Sun and the 5 largest planets at a scale of
3200 km/pixel. (Earth is the tiny spot between Jupiter and the
Sun).
![[small worlds]](gif/SmallWorlds.gif)
This composite shows Earth and the remaining 11 large solar system
objects at a scale of 100 km/pixel.
Distance Radius Mass Name Orbits (000 km) (km) (kg) --------- ------- -------- ------- ------- Sun 697000 1.99e30 Jupiter Sun 778000 71492 1.90e27 Saturn Sun 1429000 60268 5.69e26 Uranus Sun 2870990 25559 8.69e25 * Neptune Sun 4504300 24764 1.02e26 * Earth Sun 149600 6378 5.98e24 Venus Sun 108200 6052 4.87e24 Mars Sun 227940 3398 6.42e23 Ganymede Jupiter 1070 2631 1.48e23 + Titan Saturn 1222 2575 1.35e23 + Mercury Sun 57910 2439 3.30e23 + Callisto Jupiter 1883 2400 1.08e23 Io Jupiter 422 1815 8.93e22 Moon Earth 384 1738 7.35e22 Europa Jupiter 671 1569 4.80e22 Triton Neptune 355 1353 2.14e22 Pluto Sun 5913520 1160 1.32e22
*Note: Neptune is slightly denser than Uranus.
+Note: Mercury is much denser than Ganymede and Titan.
There are 13 moons whose radius is less than 20 km:
Distance Radius Mass Name Orbits (000 km) (km) (kg) --------- ------- -------- ------- ------- Deimos Mars 23 6 2.00e15 Leda Jupiter 11094 8 5.68e15 Adrastea Jupiter 129 10 1.91e16 * Pan Saturn 134 10 ? Phobos Mars 9 11 1.08e16 * Calypso Saturn 295 13 ? Cordelia Uranus 50 13 ? Ananke Jupiter 21200 15 3.82e16 Atlas Saturn 138 15 ? Telesto Saturn 295 15 ? Helene Saturn 377 16 ? Ophelia Uranus 54 16 ? Sinope Jupiter 23700 18 7.77e16
*Note: Adrastea is much denser than Phobos.
Of course, there are thousands of smaller asteroids and comets.
There are 12 major bodies brighter than magnitude 6 (as viewed
from Earth). All of these can be seen with the naked eye or with
binoculars.
Distance Radius Name Orbits (000 km) (km) Vo * --------- ------- -------- ------- --- Sun ? 0 697000 -26.8 Moon Earth 384 1738 -12.7 Venus Sun 108200 6052 -4.4 Jupiter Sun 778000 71492 -2.7 Mars Sun 227940 3398 -2.0 Mercury Sun 57910 2439 -1.9 Saturn Sun 1429000 60268 0.7 Ganymede Jupiter 1070 2631 4.6 Io Jupiter 422 1815 5.0 Europa Jupiter 671 1569 5.3 Uranus Sun 2870990 25559 5.5 Callisto Jupiter 1883 2400 5.6
*Note: Vo = Object's magnitude in visible light at opposition.
Note: Comets are often quite bright during their brief passage near the Sun.
Warning: Do NOT look directly at the Sun. Looking directly at the Sun can cause severe eye damage; doing so with binoculars or a telescope can cause permanent blindness.
There are 11 major bodies whose density is greater than 3
g/cm3:
Radius Mass Name (km) (kg) Dens * --------- ------- ------- ---- Earth 6378 5.97e24 5.52 Mercury 2439 3.30e23 5.42 Venus 6052 4.87e24 5.26 Adrastea 10 1.91e16 4.5 Mars 3398 6.42e23 3.94 Io 1815 8.93e22 3.53 Moon 1738 7.35e22 3.34 Elara 38 7.77e17 3.3 Sinope 18 7.77e16 3.1 Lysithea 18 7.77e16 3.1 Europa 1569 4.80e22 3.01
*Note: Density is in grams per cubic centimeter.
Note: Data for the smaller satellites are not very accurate.
There are also many dense asteroids, especially the M-types.
Name Why --------- ------- Earth :-) Mars most Earth-like; more so in the past; ALH84001 Europa may have liquid water Enceladus may have liquid water Titan complex chemistry and liquids likely Io complex chemistry, warmer than most Jupiter long shot: warm, plenty of organic material
The Mars meteor results notwithstanding, all of this remains very speculative. None of these prospects are really very good. Good arguments can be made why life (at least life as we know it) cannot exist on any of these bodies. (More speculation about life on Europa and Enceladus.)
