Facts About Mercury

• It is the second smallest planet in our solar system – only Pluto is smaller.

• It is smaller than Ganymede and Titan, the largest moons orbiting the planets Jupiter and Saturn respectively.

• Because the planet is so close to the sun at all times, it can be hard to see. The best times to view it are just after the sun has risen or set.

• Mariner 10 is the only spacecraft to have visited the planet. Another one, launched in 2004 is scheduled to orbit the distant planet in 2011 after making a series of fly-bys.

• Just under half of the planet’s surface has been mapped.

• Of the surface that has been mapped, most of it is extremely cratered, similar to that of the moon.

• It is the most cratered planet in our solar system.

• Other surfaces are remarkably smooth, possibly due to volcanic activity on the planet.

• The temperatures on Mercury’s surface vary greatly with the lows reaching minus 300 degrees Fahrenheit, and the highs reaching an incredible 800 degrees Fahrenheit.

• Surprisingly, radar has found what might be ice water in the cold shadows cast off by some of the crater walls.

• Despite being so close to the sun, the planet isn’t actually the warmest in our solar system. Parts of it are actually the coldest.

• It is the second densest planet in our solar system, after only the earth.

• There are no known satellites that orbit Mercury.

• It has a very small magnetic field – about one percent of the size of the field seen here on earth.

• Mercury’s core encompasses most of the planet and is made mostly from iron.

• Despite the large amounts of iron under the surface of the planet, there is no evidence of iron on the surface.

• If you were standing on the dark side of Mercury (the side not facing the sun) you would be able to see billions of stars.

• If you were standing on the light side of the planet (the side where the sun is visible) it would appear that the sun is two and a half times larger than we see it here on earth.

• A year on the planet takes 88 days.