Original Title:

Tracking Jupiter Moons

Keywords:

jupiter moons galileo mass

Description:

Galileo discovered the four largest moons of Jupiter in 1610, and
they are often referred to as the Galilean Moons. He was using a simple
telescope and a keen mind. It is a testimony to his observational prowess
that out of all the stars and bright objects he could see in the sky, he
noticed that Jupiter and these four dimmer lights, which he assumed
were stars, were stretched out along
a straight line. When he looked again
he saw that the positions had changed
from one night to the next, which is
not what stars do. After repeated
observations he determined that they
were moons orbiting around Jupiter.