Bob Moler's Ephemeris Blog

Ephemeris for Tuesday, March 5th.  The sun will rise at 7:12.  It’ll be up for 11 hours and 23 minutes, setting at 6:35.   The moon, 1 day past last quarter, will rise at 3:29 tomorrow morning.

Last week we got the news that a newly discovered comet C/2013 A1 (Siding Springs) would come very close to the planet Mars.  The calculated least distance from Mars was 0.  That means the comet does have as of now a 1 in 7000 chance of hitting the Red Planet.  Better it than us I’d say, but the U.S. have several billion dollars of assets on and orbiting Mars: two rovers and two satellites, plus another due to arrive just before the comet passes through.  The expected miss distance will be several tens of thousands of miles a bit farther than the asteroid that passed us a few weeks ago.  It’s the uncertainty that puts Mars in the cross-hairs.  Also comets are messy with a coma or a head of debris tens of thousands of miles in diameter.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

One item I forgot to mention in the program is the date of the comet encounter.  It’s October 19, 2014.

The two NASA rovers are Opportunity, operational since 2004, and Curiosity just landed last August.  The satellites are  Odyssey, and Mars Reconnaissance Orbiter.  To arrive next year the Maven satellite.

Emily Lakdawalla of the Planetary Society and Phil Plait the Bad Astronomer have the information.