21 new moons around Jupiter.

[SpaceGuy]

21 new satellites of Jupiter have been found this year. Many are thought to be due to an ancient collision of a larger moon with a comet.

Jupiter has four large moons and dozens of smaller ones (there are 60 satellites known so far). Galileo first discovered the four largest moons of Jupiter, Io, Europa, Ganymede, and Callisto in 1610, using a 20-power telescope; these moons are known as the Galilean moons.

The moons of Jupiter are (in order by their distance from Jupiter): Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede (the biggest), Callisto (the second biggest), Leda (the smallest), Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae, Sinope, and many newly-discovered moons that haven't been named yet.

In the time it took to write this more might have been found.

[:D] Jovian Factsheet. (http://nssdc.gsfc.nasa.gov/planetary/factsheet/joviansatfact.html)

[guitarusa2001]

on a tv show they asked which planet had the most moons, i answered jupiter, i felt so stupid...it was saturn [b(]

[Phobos]

Originally posted by guitarusa2001
on a tv show they asked which planet had the most moons, i answered jupiter, i felt so stupid...it was saturn [b(]

Don't. You were correct. Jupiter has more discoverd moons than Saturn (61 vs. 31 by my last count). But moons are being discovered fast and furious now...back in Jan. 2001, Saturn did have the most known moons (31 vs. Jupiter's 28 known moons at that time).

[Phobos]

By the way, welcome to Physics Forums, SpaceGuy & guitarusa2001! [:)]

[Kerrie]

being that jupiter and saturn are considered "gas" planets, would they almost have a mini solar system of their own with all of these satellites orbiting around? does jupiter or saturn cause weather patterns for these moons?

[guitarusa2001]

Jupiter causes tidal fluctuations on its moons (which is why IO is so hot) its like what the moon does to the earth except on an extemely massive scale