Planet Profile: Mercury

The Solar System, the wonders of our night sky for millennia. In this series, we’ll be looking at each planet in detail and investigating how they interact with each other. So wander your eyes up to the wandering stars in the heavens and look at them in a new way: past, present and future.

This planet profile will be on Mercury


Mercury Fact File

Distance from Sun in km65.574 million
Distance from Earth in km247.23 million
One year88 Earth days
One day58d 15h 30m
Avg temperature during day in C427
Avg temperature during night in C-173
Main materials made ofSilicate crust and mantle and iron sulphide core
Number of moons0
Size of rings in kmN/A
Avg diameter in km4,879.40
Type of planetRocky
First recorded discovery265 B.C.
First recorded discovererTimocharis
Meaning of the name in RomanMessenger of the gods


Mercury’s formation is pretty simple as planets go. The planet built up from rocks colliding and sticking together to the size that it is now, just a little bigger than the moon. It is thought that Mecury has always been close to the sun and its orbit has been fairly constant.


History of Exploration

As Mercury is the innermost planet in our solar system, it has extreme heat conditions due to the sun. The sun ejects bits of plasma all the time and this is called the solar wind. The earth has a magnetic field to protect itself from this solar wind, but as Mercury is closer to the sun and doesn’t have a magnetic field there is a lot of solar wind and risks electronics getting damaged. Because of this only two missions have been sent to Mercury. These are Mariner 10 and MESSENGER. Mariner 10 was launched in late of 1973. Its primary objective was to observe the atmosphere, surface and physical features of Mercury and Venus. It used the gravitational field of Venus to “slingshot” to Mercury. As Mercury was very close to the sun it was hard to maintain a stable orbit around it and ended up orbiting the sun instead. Mariner 10 ended up doing three flybys of Mercury but as Mercury was facing the sun all three times it only photographed 45% of its surface. MESSENGER (MEcury Surface Space ENviroment GEochemistry and Ranging) was the second Mercury mission launched in early 2004. It took MESSENGER almost six and a half years before making it to Mercury after many gravitational “slingshots” off Earth and Venus. After arriving at Mercury it did three flybys before entering orbit in 2011. By early 2012 MESSENGER had taken over 100,000 images and by early 2013 it had mapped 100% of the surface. Three years after the expected ending of the mission MESSENGER crashed into the surface of Mercury after having a decaying orbit.


Leave a Reply

Your email address will not be published. Required fields are marked *