Feeling a little hot? That's no surprise, because we've just landed on Mercury, the first, and second hottest planet in our Solar System.

Mercury's temperature can soar to over 800° F in the day, and drop amazingly to -300° at night. Sure isn't the kind of weather you'd want to live in, huh? Because of Mercury's intense climate, only one space probe, the Mariner 10 has visited the second smallest planet in our Solar System.

Ever looked at the moon at night? Mercury looks extremely like the moon; it is small, and absolutely covered in craters. In fact, some of the craters are so deep that the sun never reaches the bottom of these craters. One crater named the Caloris Basin is even wider than the state of Texas!!! Mercury has so many craters partly because it doesn't have a very thick atmosphere to slow down asteroids and meteors. (The atmosphere is made mostly of sodium and helium.)

Since Mercury is the closest planet to the sun, (about 57,900,000 km away) it has a very short year of only 88 days long!

Long, long ago, Mercury was thought to have had a huge crash collision with an asteroid. Huge shock waves went through the planet, and Mercury was almost entirely destroyed.

Because of it's very thin atmosphere, sound does not travel well on Mercury. If you were to try to scream to someone only a few feet away from you, nothing would be heard.

Now that you've learned a little about Mercury, let's move on to Venus!