Tag Archives: Mercury

Solar System Exploration – Mercury

mercury 3

Mercury is the closest planet to the sun, it’s surface is very similar to the moon, rocky and cratered but with the difference that it’s surface temperature ranges from 430°C to – 180°C. Mercury orbits the sun every 88 days and completes two rotations for every three orbits around the sun – making a day on Mercury 176 days long.


Facts about Mercury

  • Diameter: 4,878km
  • Mass: 0.055 x Earth
  • Mercury is home to one of the largest impact craters in the solar system. It’ diamter is the lenth of over 16,400 football fields.
  • Mercury has no moon.

Becasue Mecury (This applies to Venus too) orbits the sun within the orbit of the Earth is tis only visible at either dawn or dusk. It’s also possible to see cresent phases on these planets (if viewing ith through a powerful telescope) as you might see them on the moon. This again is something that is unique to the two innermost planets. The outer most planets may show slight signs or phases at extremes of their orbit in relation to the Earth, but the signs aren’t significant.




Gustav Holst wrote a suite of classical music pieces on the planets. This was the piece that he wrote for Mercury – the messenger. Probably so called becasue it rounds the sun in it’s swift 88 days.



Recent Events

The messenger probe that was launceh in 2004 carried out extensive study of Mercury and despite it’s searnly hot surface there is evidence of water ice in Mercury’s permanently shadowed craters. This shows that at some point there must have been an atmosphere on Mercury at some point and could prove to be a useful fuel and oxygen resource.

On May the 9th (today) Mercury transist the sun (pass across it) and will be visible as a tiny black dot. DO NOT look at this through a telescope. Find out more about Mercury and the transit here:

I hope you al like this new feature, I always welcome suggestions and there will be weekly posts (I hope) on objects going further out from the sun.

Simon 🙂

Credit for link information and images – NASA