The planet Mercury cannot be viewed this month since it is behind the sun, in relation to Earth.
Brilliant Venus can be spotted very low in the southeast at dawn during the first week of January. It will then sink lower each day and will disappear into the solar glare as it swings behind the sun. Venus will not be visible again until the last part of May, when it will appear during evening twilight.
Reddish Mars, currently at a great distance from Earth, appears tiny and dim even in binoculars. Look for it low in the southwest at nightfall.
Jupiter shines brightly, high in the southeastern evening sky. Look for it in the constellation Taurus, between the Pleiades and the red giant star, Aldebaran. On the evening of Jan. 21, a waxing gibbous moon will be very close to Jupiter.
Saturn rises in the southeastern sky after midnight at the beginning of January and is high in the south-southeast at dawn.
The Quadrantid Meteor Shower peaks on the night of Jan. 3-4 with up to 40 per hour. The near last quarter moon will brighten the sky and drown out many of the fainter meteors. If possible, view from a dark site after midnight.
THE PLEIADES STAR CLUSTER
"Many a night I saw the Pleiades, rising thro' the mellow shade,
Glitter like a swarm of fireflies tangled in a silver braid."
- Alfred, Lord Tennyson, Locksley Hall
The most famous star cluster in our winter night sky is the Pleiades, also known as the Seven Sisters. Since the grouping is easily visible without any optical aid, nearly everyone has noticed it at one time or another. Located only about 440 light years away, it is one of the closest star clusters to Earth and, therefore, one of the brightest in our sky. The distance to the cluster was refined several years ago by astronomers working with the Hubble Space Telescope. The fine guidance sensors on Hubble measured the very slight changes in the apparent positions of three stars inside the cluster when viewed from opposite sides of Earth's orbit. These measurements were taken at six-month intervals over a 2--year period. This technique for determining astronomical distances is known as triangulation or parallax and is only accurate with objects that are within 500 light years of Earth.
Throughout all of recorded history, this cluster has played an important role in the mythology of many religions and cultures. In 1771, Charles Messier incorporated the Pleiades into his famous list of nebulae and star clusters as No. 45 and it is now widely known as M45.
On any clear evening this month, look (see star map) nearly directly overhead, and you'll notice this small, tight cluster of stars that has intrigued people since ancient times. With 20/20 vision, most people can detect six or seven individual stars in this group, from a very dark site on a night with good "seeing." Although only nine of the brightest stars have names, more than 1,000 additional lower mass stars have been detected in the cluster by several of the world's largest telescopes. All of the stars in the cluster, many of which are extremely hot and remarkably luminous, are moving in the same direction across the sky at about the same rate of speed.
The stars in the Pleiades Cluster are relatively young compared to our sun. They formed out of a massive dust cloud about 100 million years ago. Sharp-eyed dinosaurs may have looked up from the prehistoric Earth at a faint hazy patch in the night sky, the region where the stars of the Pleiades were being born. Our sun, in comparison, was born out of a cosmic dust cloud approximately 4.76 billion years ago.
Astronomers now believe that most open-star clusters that are loosely held together by their own gravity, like the Pleiades, are eventually broken up by the tidal gravitational field of passing interstellar clouds, which are actually huge molecular complexes. In fact, at the current time, a vast cloud is blasting its way through the Pleiades Cluster at a high rate of speed. This cloud is made up of cold gas and dust, and these particles reflect the brilliant light from the nearby superbright stars in the cluster. Through a large telescope, this illuminated gas appears blue because, like smoke, the microscopic particles scatter blue light more than other wavelengths.
Since the particles are aligned by the powerful magnetic fields between the stars, photographic or CCD images of these interstellar clouds in the cluster appear streaky in structure.
If we get a clear night this month, don't miss the opportunity to see this beautiful cluster through binoculars. Although most people with good eyesight can count only six or seven stars that are arranged in the shape of a tiny dipper, people with exceptional eyesight can see more. The record was set in 1935 when veteran deep sky observer Walter Scott Houston discerned 18 individual stars on a crystal clear night from Tucson, Ariz. Give it a try, and see how well you can do.
Editor's note: This monthly guide to the stars is from the Marshall Martz Memorial Astronomical Association and The Post -Journal. For further information, contact the M.M.M.A.A. at www.martzobservatory.org.