Diameter: 4880 km
Length of Day: 720 hours (30 Earth days)
Length of year: 88 Earth days
Average temperature: 166o C
Mercury is the closest planet to the sun. It is also the smallest planet in the solar system. Because it circled the sun in only 88 days, Mercury was considered a speed demon by early Roman sky-watchers and was thus named after the Roman God Mercury, the messenger of the gods who is known for his speed.
Mercury has an atmosphere made mostly of nitrogen. Scientists believe that Mercury has an iron core that shrank when it cooled causing the surface to fold and wrinkle which would explain how some of Mercury’s cliffs and valleys came to be.
Life on Mercury would be impossible for a variety of reasons.
First, the atmosphere consists mostly of nitrogen which is considered unbreathable for most organisms on Earth. Those who inhale nitrogen do it along with other gases like carbon dioxide and oxygen. Inhaling only nitrogen would not be possible.
Second, due to its close proximity to the sun, the temperature on mercury can reach as high as 400o C.Since no form of life can survive this high temperatures, scientists have eliminated the possibility of life on Mercury.
Now, for all the amateur astronomers there, Mercury is hard to see in the night sky because it is so close to the sun. Still, for those stubborn minded ones who won't leave Mercury alone till they see it, the best time to look for it would be when its orbit takes it furthest from the sun. It can be viewed right after sun-down or before dawn when the sun is just below the horizon.
-By Aarav Iyer