University of Minnesota
January 17, 2013
Image from NASA's Curiosity rover of a martian rock showing veins that may be the result of water moving through fractures in the rock and depositing calcium-rich minerals. Image: NASA/JPL-Caltech/MSSS
With Venus and Mars dropping out of the morning and evening skies, respectively, Jupiter and Saturn are the only bright planets visible for all of February.
Saturn, a morning planet, starts rising in the east before midnight and ends the month coming up around 10:30 p.m. It keeps appearing earlier because Earth is catching up to it in the orbital race. Bracketing the ringed planet are bright Spica, in Virgo, to the west and giant red Antares, the heart of Scorpius, to the east.
February evenings belong to the knot of bright winter constellations with Orion at the center. Jupiter continues to pump out the wattage near Aldebaran, the eye of Taurus. And this is the best time to see Sirius, the brightest star, following at Orion's heels in the constellation Canis Major.
February's full moon shines the night of the 25th-26th. Algonquin Indians called it the full Snow Moon, as snows tended to be heaviest this month. It was also called the full Hunger Moon, because hunting was difficult.
If you're under dark skies an hour or two after sunset in late February, you may notice a faint oval glow extending from the horizon along the sun's path. This is the zodiacal light, the result of sunlight glinting off dust that extends far out into space in the plane of the solar system.
Groundhog Day began as a Celtic holiday called Imbolc, meaning lamb's milk, marking the halfway point between the winter solstice and the spring equinox (and the start of the lambing season). It was held that if the day was cloudy, that portended rains to soften the earth and hasten planting, hence the tradition that not seeing shadows means spring is right around the corner.
A new comet, Pan-STARRS, is on astronomers' radar and will swoop closest to Earth and the sun in March. If it brightens enough, it could become visible above the sunset horizon. We'll see.
Although Mars is all but gone from sight, NASA's Curiosity rover continues to send back images of its investigations inside the Red Planet's Gale Crater. Some recent pictures show rock streaked with veins, similar to veins that formed in Earth rocks when water flowing through cracks deposited calcium-rich minerals. Curiosity is, at this writing, getting set to drill into rock, looking for signs that the planet could have supported microbial life.
The University of Minnesota offers public viewings of the night sky at its Duluth and Twin Cities campuses. For more information and viewing schedules, see:
Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet
Twin Cities, Minnesota Institute for Astrophysics (during fall and spring semesters): www.astro.umn.edu/outreach/pubnight
Check out the astronomy programs at the University of Minnesota's Bell Museum ExploraDome: www.bellmuseum.umn.edu/ForGroups/ExploraDome/index.htm
1/18/13 Contact: Deane Morrison, University Relations, (612) 624-2346, firstname.lastname@example.org
Find U of M astronomers and links to the world of astronomy at http://www.astro.umn.edu.