By David Ward
As soon as it gets dark, go out and look to the east for a really bright object up there in the sky. If it is moving, it is probably the International Space Station or an airplane. If it is not, congratulations, you have found Jupiter. To make sure, check and see if it is twinkling. Stars twinkle and planets do not, so if it is shining steadily then you know it is Jupiter. Also, you should be able to detect a yellowish hue.
A small telescope or spotting scope will reveal its four large moons. If you look night after night, you will notice they are in different positions, performing an intricate dance around Jupiter. Galileo was the first person to observe these moons and their motions. He came to the conclusion that the earth and other planets circle the sun just like the moons orbit Jupiter, a very radical idea for his time.
Right near Jupiter there is a star that is not nearly as bright. That is Spica, the brightest star in the constellation Virgo. Left of Jupiter, a brighter orange-looking star is Arcturus in the constellation Bootes.
You may notice that the really bright and beautiful planet Venus is no longer dazzling us in the western skies just after sunset. If you miss her enough, you can get up early in the morning and find her where she has taken up residence in the east just before sunrise.
The planet Mars is still up there in the west just after it gets dark, but it is not nearly as bright or interesting as Venus. Look closely and you can identify it by its reddish color.
Early April is the best time all this year to see the elusive planet Mercury. Look for it low in the west just above where the sun went down before it gets completely dark. A pair of binoculars may help you to tease it out of the twilight glow.
Gliese 710 is coming
There are plenty of things to worry about in these troubling times. Just in case you wake up in the middle of the night and realize you are tired of worrying about the same old boring stuff, here is something new to fret about: Gliese 710, and I bet you never even heard of it. It is a small star, a little smaller than our sun, in our cosmic back yard. There are plenty of these, but what makes this one special is that it is barreling through space headed straight for us.
It is not going to hit the earth or our sun, which would be catastrophic for us, to put it mildly. It is going to plow right through something called the Oort Cloud, a vast reservoir of comets, hundreds of billions or even trillions of them, way out beyond the orbit of Pluto at the very edge of our solar system. Every now and then a comet falls out of this cloud into the inner solar system and if we are lucky, we get to see it for a while in our sky.
So what is the big deal of a few comets getting buzzed by a small star? Think of the Oort Cloud as giant hornet’s nest. Leave it alone and everything is fine. Throw a rock at it, and you better watch out. That is exactly what Gliese 710 will do. Millions of comets may fall into the inner system like angry hornets and some of them may hit us. Remember what happened to the dinosaurs 65 million years ago? This barrage may last for a million years or more, but you do not have to rush out and buy collision insurance tomorrow. Gliese 710 is not expected to arrive for another million years.
If you have not put Aug. 21 on your calendar, be sure to do so. That is the date for the Great American Eclipse of the sun, the first and last for many years. If you do not have accommodations booked on the eclipse path, do not worry about it. They have all been booked for over a year anyway. Find a place nearby and just drive to a viewing spot that day. Stay tuned for more about this event of a lifetime later.