Cumberland Times-News

February 1, 2014

Orion and Jupiter are ruling evening skies

Bob Doyle, Columnist
Cumberland Times-News

— Orion, the brightest of the 88 constellations, is now striking in the south around 8 p.m.

Look for a rectangle tipped by four bright stars. In the middle of the rectangle are three matched stars in a row. This star row is called Orion’s belt.

Orion’s belt points left and down to Sirius, the night’s brightest star.  The bottom right star of the rectangle sparkles white and blue; this is Rigel, Orion’s brightest star (say RYE-gel). Rigel’s light takes about 900 years to reach the Earth.

The upper left rectangle star is pinkish Betelgeuse, an aging star that is greatly distended as it nears the end of its life.

Betelgeuse is so large that it can enclose the orbit of the planet Mars.

When heavy stars exhaust their nuclear fuel, their central core collapse rapidly and then rebound. This leads to the outer layers of the stars being blown off, forming heavy elements such as silver, gold and platinum. This self-destruction of a heavy star is called a supernova type II.

The chance of Betelgeuse exploding is 1 out of a hundred in this century. Betelgeuse is about 375 light years. If the light of this star’s explosion reaches Earth, Betelgeuse would appear as an intensely bright point, as bright as our full moon!

For all we know, Betelgeuse may have already gone supernova, but not enough time may have elapsed for the explosion’s radiation to reach Earth.

Because of the nature of supernova explosions, Betelgeuse would remain intensely bright for a number of months after the light of the explosion first reached Earth.

Betelgeuse is so distant that the intense radiation emitted by its explosion would be so diluted that it would not endanger life on Earth.

A supernova explosion much closer (30 light years away) might cause a mass extinction of life on Earth.

Above and to the left of Orion is the bright planet Jupiter. Jupiter is so large (11 times as wide as the Earth) with its highly reflective clouds so that Jupiter always outshines any of the night stars.

You can be sure that you are seeing Jupiter by its steady light, Binoculars held steadily will show several “stars” on either side of Jupiter.

These “stars” are Jupiter’s large moons. Because of Jupiter’s large mass (318 times Earth’s mass), these large moons must move rapidly around Jupiter with periods from 1.75 to 17 Earth days.

In morning dawns of February, Venus is a splendid sight in the east. Venus’ brilliance is due to its highly reflective clouds and closeness to both the Earth and the sun.

Starting this month, Venus will be prominent at dawn for seven months. During this time, Venus will keep ahead of the Earth.

Then in September, Venus will drop close to the southeast horizon and become increasingly difficult to see. (Venus’ disappearance in October is due to our neighbor world nearly passing in back of the sun.)

SKY SIGHTS AHEAD: The crescent moon can be seen low in the western dusk for the next few evenings. On Feb. 6, the evening moon will appear half full (like a tilted letter D.)

Along the moon’s straight edge (on the left), the sun is rising there, lighting up the crater rims and mountain peaks. Binoculars held steadily will allow you to see the larger craters and the grey lava plains.

Bob Doyle invites any readers comments and questions. E-mail him at rdoyle@frostburg.edu . He is available as a speaker on his column topics.