Thursday, February 5, 2009

How Much Earlier Would A Star Rise and Set On Mars Each Night?

excellent question...i'm glad you asked that.....because....

on earth there are 86,164 seconds in a day and 365.25 days in a year. now because of the fact that the earth revolves around the sun in said 365.25 days, a star at any location in the sky at a particular time (say oh, i don't know, just off the top of my head..., that's ironic...that was what time my camping trip was ruined today due to high winds) will be in that position 3 minutes 55.904 seconds earlier for each subsequent night (86,164/365.25), until a year later when it will be in the very same position at that very same time once again. and for those keeping score, the star will have "moved" approximately 59.14 arcminutes each night or the width of nearly two, count 'em, TWO full moons! (let's discount the minor shifts due to precession [about 49.85" {in this case the symbol, " , means arcseconds not inches}/year or the size of a dime at 74.5 meters...that is of course a very rough estimate using only "stone knives and bearskins" (in THIS case,", means quotes not inches OR arcseconds)] )

on mars there are 88,775.244 seconds in a day (martian sol) and 668.5991 of those sols in a martian year which means that a star would be in a particular position in the sky 132.778 of your Earth seconds earlier each night.