T
ethys was discovered by Giovanni Cassini in 1684. It is
an icy body similar in nature to Dione
and Rhea. The
density of Tethys is 1.21 gm/cm3, indicating that it is composed
almost entirely of water-ice. Tethys's icy surface is heavily cratered
and contains cracks caused by faults
in the ice. There is one enormous trench on Tethys about 65 kilometers
(40 miles) wide and extending from above the center to the extreme left.
It covers three-fourths of Tethys' circumference. The fissure
is about the size scientists would predict if Tethys were once fluid and
its crust hardened before the interior. The canyon has been named Ithaca
Chasma.
A vast expanse of relative young plains also exists on Tethys. Tethys'
surface temperature is -187° C (-305° F).
| PHYSICAL DATA FOR TETHYS | |
|---|---|
| Mass (kg) | 7.55e + 20 |
| Mass (Earth = 1) | 1.2634e - 04 |
| Radius (km) | 530 |
| Radius (Earth = 1) | 8.3098e - 02 |
| Mean Density (g/cm3) | 1.21 |
| Mean Distance from Jupiter (km) | 294,660 |
| Magnitude (V0) | 10.2 |
| ORBITAL DATA FOR TETHYS | |
|---|---|
| Rotational period (days) | 1.887802 |
| Orbital period (days) | 1.887802 |
| Mean orbital velocity (km/s) | 11.36 |
| Orbital eccentricity | 0.0000 |
| Orbital inclination (degrees) | 1.09 |
| Escape (km/s) | 0.436 |
| Albedo | 0.9 |
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