Although the Mars Curiosity rover has made a lot of important discoveries about Mars, it hasn't really covered a very great distance in its exploration.
In fact, just last year, the odometer of the rover, which landed on the Red Planet in 2012, hit the 10K mark: that's only a little over six miles.
For those not following the mission, that could seem surprising. One Reddit user, PEEnKEELE, decided to put that into perspective and mapped out the distance traveled by Curiosity on Google Maps, zooming in on the island of Manhattan.
Manhattan is 13.4 miles long, but when Curiosity's path is laid over the island on the map, there's still a lot of territory not covered.
Basically, this is a reminder that, although we've learned much about Mars thanks to Curiosity, there are probably millions of miles of the Red Planet that we won't learn anything about anytime soon because Curiosity moves so slowly.
There is good reason for this, though. The first is simple logistics: rovers are expensive, difficult to repair and carry a lot of hefty equipment. Racing across the surface of Mars isn't a priority: keeping the rover intact and working is. Every move Curiosity makes is one that NASA pre-planned years in advance.
Curiosity is also not just roaming the surface of Mars. It's doing scientific experiments, too, such as drilling into the planet and searching for signs of water and life. This is painstaking work that takes time, meaning that Curiosity spends a lot of time standing still while it works.
The rover also isn't moving in a straight line. The path is rather wibbly wobbly, because NASA has marked locations on the planet where it wants the rover to go. NASA carefully chose these locations for scientific reasons, so they're important to the research that Curiosity does.
"We've not only been making tracks, but also making important observations to characterize rocks we're passing, and some farther to the south at selected viewpoints," Curiosity science team member John Grant of the National Air and Space Museum in Washington said in a statement last year.
"The rover's mobility has been crucial, because that's what allows us to get to the best sites to investigate," Grant added. "The ability to get to different sections of the rock record builds more confidence in your interpretation of each section."
So, Curiosity hasn't traveled far, but it's done a lot in its four years on the Red Planet, making way for discoveries that will eventually put humans on the surface of Mars.
