Moons

October 11, 2019

What is a Moon?

With the discovery this week of 20 New moons around Saturn, we thought it would be a good idea to look at the moons of our solar system.  Planets and asteroids in our solar system orbit the Sun. Moons — also known as natural satellites — orbit planets and asteroids. There are more than 200 moons in our solar system. Most orbit the giant planets — with Saturn and Jupiter leading moon counts — but even smaller worlds like Pluto can have five moons in orbit.

Moons come in many shapes, sizes and types. Most are airless, but a few have atmospheres and even hidden oceans. There are dozens of moons in our solar system — even a few asteroids have small companion moons.

Mercury doesn´t have any moon´s.  It orbits too close to the sun.  If it it were to have any its own gravity wouldn´t be strong enough to keep them in it´s orbit.  They would be pulled towards the sun and eventually in to it.   It is still a mystery as to why Venus doesn´t have any moons.  Earth, however, has just one.

Earth’s Moon is the only place beyond Earth where humans have set foot.  The brightest and largest object in our night sky, the Moon makes Earth a more livable planet by moderating our home planet’s wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years. The Moon was likely formed after a Mars-sized body collided with Earth.

Our moon is the fifth largest of the 190+ moons orbiting planets in our solar system.

Earth’s only natural satellite is simply called “the Moon” because people didn’t know other moons existed until Galileo Galilei discovered four moons orbiting Jupiter in 1610.

NASA currently has three robotic spacecraft exploring the Moon — Lunar Reconnaissance Orbiter and the twin ARTEMIS spacecraft (not to be confused with NASA’s new Artemis program to send astronauts back to the Moon).

 

Mars’ moons are among the smallest in the solar system. Phobos is a bit larger than Deimos, and orbits only 3,700 miles (6,000 kilometers) above the Martian surface. No known moon orbits closer to its planet. It whips around Mars three times a day, while the more distant Deimos takes 30 hours for each orbit. Phobos is gradually spiraling inward, drawing about six feet (1.8 meters) closer to the planet each century. Within 50 million years, it will either crash into Mars or break up and form a ring around the planet.

To someone standing on the Mars-facing side of Phobos, Mars would take up a large part of the sky. And people may one day do just that. Scientists have discussed the possibility of using one of the Martian moons as a base from which astronauts could observe the Red Planet and launch robots to its surface, while shielded by miles of rock from cosmic rays and solar radiation for nearly two-thirds of every orbit.

Like Earth’s Moon, Phobos and Deimos always present the same face to their planet. Both are lumpy, heavily-cratered and covered in dust and loose rocks. They are among the darker objects in the solar system. The moons appear to be made of carbon-rich rock mixed with ice and may be captured asteroids.

Jupiter has 53 named moons and another 26 awaiting official names. Combined, scientists now think Jupiter

has 79 moons.  There are many interesting moons orbiting the planet, but the ones of most scientific interest are the first four moons discovered beyond Earth—the Galilean satellites.  The planet Jupiter’s four largest moons are called the Galilean satellites after Italian astronomer Galileo Galilei, who first observed them in 1610. The German astronomer Simon Marius claimed to have seen the moons around the same time, but he did not publish his observations and so Galileo is given the credit for their discovery. These large moons, named Io, Europa, Ganymede, and Callisto, are each distinctive worlds.

Saturn has 82 moons. Fifty-three moons are confirmed and named and another 29 moons are awaiting confirmation of discovery and official naming. Saturn’s moons range in size from larger than the planet Mercury — the giant moon Titan — to as small as a sports arena. The moons shape, contribute and also collect material from Saturn’s rings and magnetosphere.

I hope you have enjoyed reading about some of the moons in our solar system.  Personally I love looking at our own moon through our 12″ Dob and taking pictures of it.  If you want a closer look at our moon, then book with us today.

Until the next blog this is Kieran signing off.

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