Why Mars is bright

A few days ago (January 29), I posted about how Mars was nice and bright and located near the full Moon.  Mars has been about as bright as the star Sirius which is the brightest true star in the sky (planets sometimes get a little brighter).  A student asked me today why Mars was so bright lately.  The following figure should illustrate the reason:

Looking down on the inner solar system, we see that Mars and Earth are lined up on the same side of the Sun.  Astronomers would say that Mars is at opposition (opposite from the Sun).  It's relatively close to us and catching lots of sunlight to reflect back so we can see it so brightly as a reddish "star" in the night sky.

It's currently in the constellation of Cancer, halfway between Regulus in Leo and Castor and Pollux in Gemini (about half-way up in the eastern sky around 8 pm in our area).  Go out and take a peek, it's unmistakable.

Picture of the Week - Horrible cruelty

A picture from the Omi Art Center in Columbia County, NY.

The wanton cruelty shown by the heartless enslavement of rocks is almost too much to bear for a geologist like myself.

Happy Imbolc

February 2, 2010 is a Cross-Quarter Day – it’s the half-way point between the Winter Solstice, which occurred at December 21, 2009 at 17:47 UTC and the Vernal or Spring Equinox which will occur on March 20, 2010 at 17:32 UTC. The exact midpoint, by my calculations, is actually at 40 minutes after midnight on February 3 local time (EST).

Many ancient cultures celebrated this day since it has an astronomical basis and, in Europe, is often taken as the beginning of spring. On the traditional Celtic calendar it’s called Imbolc and celebrated the goddess Brigid. On the Christian calendar, this is supplanted by St. Brigid’s Day after one of Ireland’s patron saints. Another Christian holiday, Candlemas, or the Feast of Presentation of Jesus at the Temple, also occurs at this time in February and is based on the Gospel account in Luke 2:22-40.

In the secular world, we have Groundhog Day, developed in Pennsylvania during the 18th century by German immigrants. It appears to have its roots in European weather lore but there a badger or a bear was the forecaster. Also, some people see ties to Imbolc since that Celtic holiday is also traditionally associated with weather prognostication.

Whatever you celebrate, we can all enjoy the fact that we’re half-way to the to the first official day of spring!

Interesting math column

Steven Strogatz, a Cornell math professor, will be writing a blog for the New York Times about mathematics.  As he puts it:

Crazy as it sounds, over the next several weeks ... I’ll be writing about the elements of mathematics, from pre-school to grad school, for anyone out there who’d like to have a second chance at the subject — but this time from an adult perspective. It’s not intended to be remedial. The goal is to give you a better feeling for what math is all about and why it’s so enthralling to those who get it.

Sounds interesting.  Here's the first installment - From Fish to Infinity.  I look forward to reading the next.