Mars shines a brilliant red due to oxidized iron in its soil.
November brings many changes both large and small. The brilliant autumn colour on Medd’s Mountain has drained away to a uniform grey-green. The night air is somewhere between pleasantly crisp and decidedly cold. Look up and Canada geese are heading south. Look down and dead leaves are collecting into yellow drifts.
Look up again just a little higher, though, and you’ll see drifts of winter stars just coming into form, getting ready for the dazzling display that is the night sky in winter. Sure we’ve lost the balmy summer air, but that just means clearer skies as the summer haze lifts like a curtain at the start of a show.
And what a show it will be! October brought both the Harvest Moon and a second full moon known as a “Blue Moon,” an event so uncommon that it only happens once in a … well, you know how that goes. November will bring five bright planets into view: look for Jupiter in particular in the western sky in mid-November, and a burnished “star” shining just to the east of it — Saturn. Among the constellations, watch for the familiar belt and bow as Orion becomes prominent later in the month.
The main event in November, however, continues to be the spectacular show Mars has put on since it moved into opposition in October, when the earth stood directly between Mars and the sun. Look south after dinner and you will see Mars’ blazing red race about halfway to the zenith.
Dazzling as it is, though, Mars’ bright display also brings us back to earth in an interesting way.
That familiar red in Mars is caused by the oxidization of iron in the Martian soil. And where did the iron come from? From the same swirling disk of dust and gas that birthed the solar system about 4.5 billion years ago. And where was the iron before that? Forming in the fusion furnaces of the sun’s parent stars, whose explosive ends blew the iron out into the cosmos, where it eventually sifted down into the molten core and, in due course, soil, rocks, and rivers of a little planet called earth. That’s where animals evolved a fantastic mechanism for utilizing oxygen by binding it with iron in hemoglobin, otherwise known as that red stuff in your veins.
In other words, Mars may be even closer than it seems.
This Month in Astronomy by Dennis Vanderspek
