StarwatchIn March we get to watch as four planets group into two pairs. Three of the planets are in the sky and one is right under our feet.
In March we get to watch as four planets group into two pairs. Three of the planets are in the sky and one is right under our feet.
Mars reaches opposition March 3, the day Earth passes it and it appears directly opposite the sun. The Red Planet will be up all night, burning its ruddy fire below the belly of Leo, the lion. The bright star east of Mars is Regulus, the brightest in Leo.
On March 5, Mars will sweep closest to Earth and shine at maximum brightness for this visit. If it seems strange that our two worlds make their closest approach after Earth has lapped Mars, remember that both orbits are noncircular, with points of perihelion and aphelion when the planets are nearest and farthest, respectively, from the sun. Earth is heading out toward aphelion while Mars, having passed its aphelion in February, is now closing in. These motions continue to bring our two planets closer until two days after Earth has left the Red Planet behind.
Unfortunately, being so near aphelion means Mars won’t come nearly as close as it did in 2003, when its opposition and perihelion fell only two days apart. This time it will be about 63 million miles away, compared to only 35 million miles in 2003.
Also in Mars news, recent data from the European Space Agency’s Mars Express probe suggests that a large ocean once covered the planet’s northern plains. The probe’s radar picked up evidence of marine-like sediments in locations already suspected to have been ancient shorelines. Researchers speculate that the ocean enjoyed a rather brief life some 3 billion years ago.
The second planetary pairing happens March 13, when Jupiter drops past Venus on its way down into the sun’s afterglow. The king and queen of planets come within three degrees of each other, and then separate as Jupiter continues its free fall.
On March 25, a thin crescent moon comes out close to Jupiter. The next night, a slightly fatter lunar crescent appears next to Venus, just as the brilliant planet reaches its highest point before beginning a dramatic fall. With the Pleiades star cluster hovering just a few degrees above Venus, this is a night to grab your binoculars.
Saturn is well up in the east by midnight all month. Just west of the ringed planet is its companion, the bright star Spica in Virgo. Above and left of the pair is Arcturus, the brightest star in Bootes, while Mars shines high to their upper right.
Algonquin tribes called the full moon of March the worm moon, for the casts of earthworms that now begin to appear on the softening earth. In more northerly areas, it was known as the crow moon, for the cawing of these feisty birds, or the crust moon, because during this season snow acquires a crust from cycles of melting and refreezing. This year it rises the night of March 7 and reaches perfect fullness at 3:39 a.m. March 8.
High in the south during the evening is Procyon, the brightest star in Canis Minor, the smaller of Orion’s hunting dogs. Procyon is actually a double star consisting of a star twice as wide as the sun and nearly seven times as bright and a white dwarf star that packs about 60 percent of the sun’s mass into an orb smaller than Earth. Procyon isn’t especially bright; it just looks that way because it’s only about 11.5 light-years from Earth.
Procyon forms one point of the Winter Triangle of stars. The other points are Sirius—below Procyon and only nine light-years away—and the gigantic red star Betelgeuse, which forms Orion’s northeast shoulder and burns brightly despite being some 600 light-years away.
Spring arrives with the vernal equinox at 12:14 a.m. March 20. At that moment the sun crosses over the equator into the northern sky and the Earth—the other side of it, of course—will be lighted from pole to pole.
The University of Minnesota Duluth offers public viewings of the night sky at the Marshall W. Alworth Planetarium in Duluth. For more information and viewing schedules, see www.d.umn.edu/planet.
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