What’s a sol?

A Martian day is 39 minutes and 35 seconds longer than an Earth day. To distinguish the two, we use the term “sol” when referring to a Martian day.

Landers we have sent to Mars use special 24 hour clocks with longer seconds than those of Earth, so that a sol is divided into 24 periods, just like on Earth. The operations teams for these landers work and live by the same clocks. This means, for people working on these crews, their schedule shifts 40 minutes later each day. This makes for interesting problems.

Curiosity at 2000 Sols

Curiosity is at 2000 sols and still going.

(Note the comment regarding sky color)

Looks like we made it: 2,000 sols on Mars, you guys! I’m looking back on 2,000 Martian days of exploration, and…

Posted by NASA’s Curiosity Mars Rover on Thursday, March 22, 2018

Thank You, Dr. Hawking

Insurance

“We’re talking about an insurance policy—a backup plan in case something does happen to the Earth. I once talked to Carl Sagan about this, who said, “We live in the middle of a shooting gallery with thousands of asteroids in our path that we haven’t even discovered yet. So, let’s be at least a two-planet species, as a backup plan.””

https://news.nationalgeographic.com/2018/02/there-s-only-one-way-for-humanity-to-survive–go-to-mars-/