Have you seen it? That bright star shinning in the east as the sun goes down is actually the giant planet Jupiter. When viewed from earth it is the 3rd brightest object in the night sky (after the moon and venus). Jupiter completes its orbit around the sun in 11.86 years, but makes a single rotation on its axis in just under 10 hours. This rapid rotation creates an equatorial bulge, which you can see from through a telescope.
Jupiter has 64 named natural satellites i.e. moons. The four largest moons, known as galilean moons, because Galileo discovered them in 1610 are Io, Europa, Ganymede, and Callisto. To give you a sense of size, Ganymede, the largest moon has the same diameter as the planet mercury. These four moons can also be seen from earth with binoculars or a telescope.
In the spirit of the Christmas season, this week, I will be hauling out the telescope to check out this bright “star” in the east and it’s moons.