Mars Time

Someday, explorers on the planet Mars might use special clocks -- with forty extra minutes per day -- to keep track of the time.

Friday, April 2, 1999

JB: Shuttle astronauts coordinate their clocks with Mission Control Center in Houston. But future explorers on Mars might adjust their schedules to match the martian day at their landing site. They might do this gradually during the flight to Mars to avoid interplanetary "jet lag."

DB: A martian day is about forty minutes longer than an earthly day -- which creates problems for astronauts who want to stay in synch with Mission Control. One idea is to use a martian "time slip" -- clocks would stop for forty minutes every twenty-four hours. Or martian clocks might be altered to stretch the second. A day would still be divided into twenty-four sixty-minute hours, but each hour would last about sixty-two Earth minutes.

JB: During unmanned Mars missions, scientists numbered the passing Martian days -- they called them "Sols." The Pathfinder spacecraft started operations on Sol 1 and stopped transmitting on Sol 83. Martian astronauts will probably use a similar system -- but they might still keep track of birthdays and holidays using an ordinary Earth calendar. By the way, you can see Mars tonight. After moonrise in mid-evening, Mars will be the brightest object near the moon. Thanks for your question, Patrick. And with thanks to the National Science Foundation, we're Block and Byrd for Earth and Sky.