Carbon-encrusted impact crater taken from MESSENGER. Image credit: NASA/JHU Applied Physics Laboratory/Carnegie Institution of Washington

Carbon-encrusted impact crater taken from MESSENGER. Image credit: NASA/JHU Applied Physics Laboratory/Carnegie Institution of Washington

Good morning, Earthlings!

The discovery of graphite on Mercury was certainly a surprise on a few levels, but one thing that came to mind to hundreds of planetary scientists- can we make pencils?

We know Mercury lacks iron...so why is it darker than the moon? The Mercury MESSENGER orbiter found dustings of soft carbon- much more in abundance than Mars, Moon, and even Earth!

The carbon is suspected to come from Mercury's early crust (so about 4.5 billion years old!)

That is some very old pencil lead...

With Earth, minerals from magma would just crystallize and fall into the iron core. Since Mercury is only partially melted with a core, the carbon is less dense and floats to the top, waiting to get exposed from impact cratering events!

What planetary scientists are looking into now is how much abundance is that carbon on a localized and global scale!

Thank you for reading and next week we'll take a look at some spectacular Rosetta images of a bizarre comet!