Mercury A to Z: Uplands

Hello, friends!  Welcome back to the A to Z Challenge.  For this year’s challenge, my theme is the planet Mercury, and in today’s post U is for:


Science Fiction

The year is 2059.  With the benefit of newly invented gravity manipulation technology, NASA has determined that they can safely and economically place a small rover on the surface of Mercury.  The first ever Mercury rover will land in a region just south of Mercury’s equator, part of the so-called “uplands” of Mercury.

Science Fact

There are generally two types of terrain on Mercury: the smoother, flatter volcanic plains regions, which are mostly found in the northern hemisphere, and the rougher, craggier, more heavily cratered “uplands,” which are found in Mercury’s equatorial regions and extend into the southern hemisphere.

Those smoother, flatter regions formed through a process planetary scientists call “resurfacing,” which is one of my favorite scientific euphemisms.  Resurfacing sounds like something you do to a parking lot.  What resurfacing actually means, in reference to planets, is that some sort of extreme volcanic activity covered part of a planet’s surface in lava.  The lava cooled and hardened, creating a smooth new surface and covering up whatever surface topography may have been present in the past.

Mercury is not a volcanically active world today, but it must have been at some point.  Most likely, the partial resurfacing of Mercury happened shortly after the end of the late heavy bombardment, a critical period in the history of our Solar System when the inner planets got pelted with asteroids.  Lava pooled in low elevation regions of Mercury, either filling in or totally covering up craters left by the late heavy bombardment.  But higher elevation regions—the uplands, in other words—were spared from resurfacing.

Similar upland terrain can be found on the Moon, and studying the lunar uplands has told scientists much about what the Solar System was like during the late heavy bombardment.  Comparing and contrasting the uplands of the Moon with the uplands of Mercury may give us an even clearer and more detailed picture of what that era of the Solar System’s history was like.  For this reason, a mission to explore the uplands of Mercury could be very interesting and exciting for scientists.

Science Fiction

NASA apparently failed to learn their lesson after the public naming contest for their mission to Uranus and proceeded to hold another public naming contest for the Mercury Uplands Rover.  And that is how NASA’s Up-Dog Mission officially came to be.


Here is a 2016 article from NASA announcing the first complete topographic map of the surface of Mercury.

And here is an article from about the Moon and Mercury and the things we might learn by comparing and contrasting the two.

P.S.: If you don’t understand the up-dog reference, feel free to ask me “What is up-dog?” in the comments below.