When NASA's rovers, "Spirit" and "Opportunity," touch down on Mars next January, scientists and engineers in charge of the missions at the Jet Propulsion Laboratory (JPL), will start to experiment with a 90-day period of jet lag. Why? Because, as reports Astrobiology Magazine, "a day on Mars is 39.5 minutes longer than a day on Earth."
A day on Mars, which is known as a "sol," consists of 24 hours, just like a day on Earth. Each hour contains 60 minutes; each minute 60 seconds. There's nothing magical about that. Scientists simply got together and declared it to be so.
But there's a catch. A martian second is a smidge longer than what you're used to on Earth. Think of it this way: Instead of counting, "One Mississippi, two Mississippi" count "One Mississippis, two Mississippis."
Why tamper with the length of a second? Because a martian day is about 39.5 minutes longer than a terran day. By stretching each of the 86,400 seconds in a day by just a hair, those 39.5 minutes can be spread out throughout a martian sol without anyone hardly even noticing. Until, that is, it comes time to send radio signals between Mars and Earth.
And because engineers must always be synchronized with the rovers, this means a subtle shift every day.
To accommodate the requirements of interplanetary communication, during the mission the Spirit science and engineering teams will have to live "on Mars time," in synch with the red planet's cycle of light and dark. This means that, here on Earth, they'll sometimes be working during daylight hours, and at other times they'll be working through the night. Over the course of a bit more than five weeks (36.5 days), the Spirit team will make a complete cycle around the clock, shifting slightly each day.
"It totally messes you up to shift every day," says Matt Golombek, who was the project scientist for Pathfinder, and is the Science Operations Working Group chair and long-term planning lead for the MER missions. "You're not going to the bank. You're not talking to your friends. You see deer more than you see people at JPL. You're on another planet."
It might be disturbing for some people, but I wouldn't mind to be there, watching images never seen before hours or days before they appear on TV or on the Web.
The "MarsBase dot net" (your porthole to Mars), gives you the time on Mars. You'll see it is complex.
So you can try another approach and go to this page on the NASA Goddard Institute for Space Studies (GISS) website to download the Mars24 application.
Mars24 is a cross-platform Java application which displays a Mars "sunclock", a graphical representation of Mars showing the current sun- and nightsides of Mars, along with a numerical readout of the time in 24-hour format.
Here is a screenshot of the Mars24 application (Credit: Robert B. Schmunk, NASA GISS).
Sources: Astrobiology Magazine, December 15, 2003; and various websites
12:12:31 PM
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