January 2003

By Steve Stefanik

The earth reached perihelion (the closest point to the sun in its annual orbit) this past Saturday. So why are we in "the dead of winter" if we are closer to the sun you may be asking yourself? Because we don’t get any heat directly from the sun at 91 million miles away. The "heat" comes to us indirectly from solar radiation reaching the surface of the earth, which is changed into infra-red (heat) wavelengths when it passes through the atmosphere. However, we just passed the winter equinox 2 weeks ago, which means that the axis of the earth is inclined 23.5 degrees away from the sun in the northern hemisphere so that the solar radiation is striking the surface of the earth at a acute angle which means we don’t get very many hours of exposure to the sun’s radiation and the intensity of the "waves" are quite diminished. Cheer up! It’s a new year! It’s all "down-hill" from here until we reach the summer solstice on June 21. "Round and round and round we go . . . when it stops know one knows." Take advantage of the long winter nights and get out under the stars and take a look at some of this year’s spectacular sights.

If you get home from work in the early evening as the sun is setting, take a look toward the western horizon. You may be able to spot the planet Mercury hovering close-by seeing that it’s the closest planet to the sun. Its still quite bright at –0.5 magnitude although you won’t have many more days to catch a glimpse of it as it heads toward inferior conjunction with the sun on the 11^th of this month and won’t be seen again until the end of the month when it rises early in the morning in the east around dawn.

By the time Mercury "sets" in the west, the planet Saturn is fairly high in the eastern sky. Look for the Pleiades star cluster, which looks like a miniature "little dipper" above the constellation Taurus the bull which looks like a big "V" on its side. The brightest star in the constellation is Aldebaran. It’s a red-orange first magnitude star. If you look above and to the left of Aldebaran you should see another even brighter yellow-orange "star". This is Saturn. Having reached opposition just a few weeks ago, its still quite bright at –0.4 magnitude, and arcs high overhead all night long the next few months. It’s as close as it will be in the next 30 years. Take a look at it through a telescope and it will undoubtedly leave you with a life-long impression that you will never forget.

About an hour or so later an even brighter object will appear lower and to the left of Saturn among the stars of the constellation Cancer the crab. This is the planet Jupiter. Its –2.6 magnitude creamy white luster will mesmerize you. Through a telescope you will be absolutely amazed that you can see things on another "world" (clouds, storms, and moons), which is over 400 million miles away.

If it’s still dark when you get up for school or work, take a look toward the southeastern horizon. You can’t help but notice the gleaming brilliance of the –4.4 magnitude planet Venus "the morning star".

Not as apparent, nor as brilliant, the +1.5 magnitude planet Mars can be spotted higher and to the right of Venus. Look for the rusty red planet close to the red star Antares, which rivals Mars in color and brightness. Antares means "rival of Mars".