Mercury is a rocky planet, just like Earth, Venus and Mars, which means it has a solid surface that you can step on (Yes - there are planets that don’t have a surface and you can’t step on them). Mercury is also in a very special position, because it gets to be closer to the Sun than any other planet.

In addition to that, Mercury holds the title of the smallest planet in the solar system as well (we’re not including Pluto as an “official” planet here, but that’s another s) - It is so small that it’s only a tiny bit bigger than our own Moon!

Mercury can be seen in the night sky with the naked eye, that’s why ancient populations knew the planet and observed it before telescopes were invented. And the ancient Roman's named it Mercury after the messenger of their gods and goddesses.

Because in the Roman mythology, the messenger is so fast and swift delivering its messages, and Mercury is also so fast when it appears in the sky.

“Wasn’t Hermes the messenger of the gods?” we hear you ask – Yes! But that was what the Greeks called the same god.

Being the closest planet is cool and all, but it’s also very unstable! You’d think that Mercury is a hot mess all of the time - but that’s not true.

Mercury’s temperature in the daytime can go up to 430°C (800°F), and at night it drops magnificently to -180°C (-290°F).

But don’t be fooled! Just because Mercury is the closest planet to the Sun, doesn’t mean it’s the hottest in the solar system - the hottest planet in the solar system is actually…Venus!

The duration of the day-night cycle on Earth is determined by how fast the Earth rotates around itself, and the duration of the year on Earth is determined by how fast the Earth rotates around the Sun.

The Earth rotates around itself faster than around the Sun, that’s why the day-night cycle on Earth is shorter than the year – 365:1 in fact!

Mercury however, being so close to the sun, rotates around it faster than rotating around itself, therefore, the year on Mercury is actually shorter than the day-night cycle. Mercury’s year is only 88 Earth days, while its day-night cycle is almost 176 Earth days.

If you’ve found yourself struggling between two pictures not knowing which is Mercury and which is the Moon, don’t you worry - you’re certainly not alone. The surfaces of both Mercury and the Moon are so similar that they’re often mistaken for each other.

Both surfaces for example are full of craters (big holes) caused by objects hitting the bodies of Mercury and the Moon. And in pictures, they both look like quite the same size which only adds to the confusion.

We hear a lot of talk about spacecrafts going to Mars - every few years a new mission is on its way. And in the future, you and I could have a chance of visiting Mars ourselves. But what about Mercury?

Actually, it’s very hard for humans to visit Mercury because it’s so close to the Sun – our human bodies can’t cope with that weather!

In fact, we’ve done very little to study Mercury in comparison to other planets. Very few space missions have even passed by Mercury and orbited it - just two to be exact: “Mariner 10” in 1973, and “MESSENGER” in 2008.

Another future mission called “BepiColombo” will reach Mercury in 2025.