**From:** DragonFun@aol.com (by way of Jan Wee <jwee@mail.arc.nasa.gov>)

**Subject:** Mars & C-TEC's vision, Time on Mars & More

**Date:** Thu, 10 Jul 1997 09:22:33 -0500

Hello Happy Mars Explorers, I'm a volunteer mentor at C-TEC, a project-based learning community at Piner HS in Santa Rosa, CA. Here's a message I sent to a teacher I work closely with: Message to Paul Davis -------------------------------- Yassoo Paul, Pathfinder and Sojourner are alive and well on Mars and the whole world is watching. Who had the vision to explore Mars in 1993 and 1996? C-TEC! [Note. C-TEC ran simulations of establishing the first scientific bases on Mars, all day for 8 school days in Dec 93, and all morning every morning for 10 school days in Dec 96.] Continue the C-TEC Vision * Let's build Mars strands as unifying themes into your Geometry, Advanced Algebra, and Calculus courses. I'm writing some of the stuff we'll need. * Let's encourage other teachers to do the same. * Most of all, let's use the exploration of Mars to intertwingle the disciplines: math, science, humanities. In our lifetimes, there will never again be a unifying theme as great as this one to capture the imagination of students, teachers, and parents. The exploration of Mars will be in the news for a decade or two or more. Mariah MacDonald said it well--I forwarded her posting to discuss-lfm to all C-TEC teachers, Eric Burgess, Richard Zimmer, others. * Gonzo's idea about C-TEC hosting online stuff for local schools is terrific. It's called "distance learning" in the educational media. Let's do it. End message to Paul Davis ------------------------------- About time on Mars First, a question. Is one sol the time for one Mars sidereal rotation or for one Martian rotation relative to the sun? The best source of planetary data I know is the National Space Science Data Center at http://nssdc.gsfc.nasa.gov Scroll on down to the Disciplinary Services section and click Planetary Sciences. On the Planetary Sciences page <http://nssdc.gsfc.nasa.gov/planetary>, scroll down to NSSDC Resources and click the name of the planet for which you want data--Mars, of course! >From NSSDC: * Earth's sidereal rotation period is 23.9345 hours. * Earth's solar day is 24 hours (exactly). * Earth's orbital period is 365.256 solar days (24 hours or 86,400 seconds) * Mars's sidereal rotation period is 24.6229 hours. * Mars's orbital period is 686.980 Earth solar days (24 hours or 86,400 seconds). Recall that the sidereal rotation period is relative to the fixed stars. This is the time required for one 360 degree rotation. An Earth solar day is the time between two consecutive crossings of the Prime Meridian by the sun at noon. The solar day is a little longer than the sidereal day because Earth moves almost 1 degree in its orbit in one sidereal rotation and has to rotate a little more for the meridian to cross the sun again. The second is a fundamental SI (metric) unit of time. Minutes and hours are derived SI units and are the same on Earth and Mars. An Earth solar day is exactly 24 hours. Put students to work on a few easy (?) exercises. Also, if I have made mistakes in presenting this stuff, please send coirrestions! * Earth's solar day is exactly 24 hours. Calculate the number of seconds in one solar day. * Earth's sidereal period is 23.9345 hours. Calculate its sidereal period in hours (h), minutes (min), and seconds (s). * Mars's sidereal period is 24.6229 hours. Calculate its sidereal period in hours (h), minutes (min), and seconds (s). * Earth's orbital period is 356.256 Earth solar days (24-hour periods). Calculate its orbital period in seconds (s). * Mars's orbital period is 686.980 Earth solar days (24-hour periods). Calculate its orbital period in seconds (s). * Earth's sidereal period is 23.9345 hours and its orbital period is 365.256 24-hour time chunks. Using only this data, calculate the length of Earth's solar day. (Answer: 24 hours.) * Earth's solar day is 24 hours and its orbital period is 365.256 solar days (24-hour periods). Using only this data, calculate Earth's sidereal period. (Answer: 23.9345 hours.) * Mars's orbital period is 686.980 Earth solar days (24-hour periods) and its sidereal period is 24.6229 hours. What is the length of Mars's solar day in hours? * Mars's orbital period is 696.980 Earth solar days. What is Mars's orbital period in Mars solar days? Well, you can probably think of many more exercises. At C-TEC, we're generating lots of Mars-related strands to use in math, science, and humanities. Reality expands to fulfill the available fantasies. Thanks, NASA, JPL, everyone who helped fulfill this beautiful realizeable fantasy of exploring Mars. Bob Albrecht