SATELLITES AND OTHER BODIES
NATURAL SATELLITES (MOONS)
The word satellite has come down from the Latin word satellites which means attendant or secondary. So, we can define a satellite as under:
A satellite is a body that revolves round another (bigger) body in space. Our moon is the satellite of our earth. Similarly, six other planets in the solar system have their moons. Only Mercury and Venus have none. The Earth and Pluto have just one moon each while Mars has two. Neptune has 8 moons whereas Jupiter, Saturn and Uranus have 16, 23 and 1 respectively.
It must also be remembered that there is every chance of more undiscovered satellites (moons) to be located around the outer planets. Besides, the smallest moon is that of Mars (Deimos) which is only 12 kilometers across. As for the largest moon, it is that of Jupiter (Ganymede) with a diameter measuring 5262 kilometers.
Apart from the satellites circling the planets, there are dark bodies that revolve around certain stars and either dim or brighten their lights. These bodies are also called satellites. The table given below shows the number of satellites that circle seven of the nine planets in our solar system.
| Planets |
No. of Moons |
| Mercury |
- |
| Venus |
- |
| Earth |
1 |
| Mars |
2 |
| Jupiter |
16 |
| Saturn |
23 |
| Uranus |
15 |
| Neptune |
8 |
| Pluto |
1 |
How was the moon (Earth's satellite) formed? One theory explains that the earth collided with some other body and as a result, some debris was scattered into space. Due to the earth's gravity, the debris began to revolve round the earth. Slowly it began to collect together and the result was our moon. May be, most of the moons have been formed in a similar way.
