With eight planets in our solar system, more than 200 moons surround those natural satellites.
Jupiter, one of the most recognizable planets, has 80 of those moons.
On this day in history, Jan. 7, 1610, Galileo discovered the moons of Jupiter — making it the first observation of this planet.
Galileo Galilei was an Italian philosopher and astronomer born in 1564 in Pisa, Italy, according to Britannica.
After moving to Florence as a young child, Galileo attended school, then went to the University of Pisa to study medicine.
While there, he became interested in mathematics — ultimately dropping out of college without a degree to work on his own.
Still, Galileo was always teaching himself new skills and facts, according to Britannica.
Galileo was best known for producing powerful telescopes — and used one of them to discover four moons surrounding Jupiter.
On Jan. 7, 1610, Galileo discovered four moons revolving around Jupiter — a discovery that would change his life forever.
These four moons are Jupiter’s largest satellites — lo, Europa, Ganymede and Callisto — also known as Galilean Moons, according to National Geographic.
This discovery helped him prove that the Earth did indeed revolve around the sun, a fact that was not accepted at the time.
Years later, Galileo faced charges for believing and advocating for the Copernican theory — the idea that the Earth revolves around the sun.
This theory was largely against the teachings of the Roman Catholic Church at the time.
He ultimately pled guilty and was put on house arrest indefinitely by Pope Urban VIII, according to History.com.
He spent the rest of his life in a villa near Florence before his death on Jan. 8, 1642.
Jupiter is fifth in line from the sun and is by far the largest planet in the solar system, according to NASA.
As for the giant red spot on the planet?
It’s a huge storm that’s bigger than Earth — having grown for hundreds of years, according to NASA.