“Follow the evidence wherever it leads, and question everything”
— Neil deGrasse Tyson
The little planet Mercury is lost in the solar glare during most of December as it swings between Earth and the sun. It will reappear very low in the east before dawn at the end of the month.
Venus is behind the sun in relation to Earth this month and, therefore, won’t be visible. This brilliant planet will not be visible until late February, when it will appear very low in the western evening twilight.
Mars rises in the east-southeast about four hours before the sun as December begins. The reddish planet is only half as bright as the blue-white variable star Spica to its right. By the end of the month, bright Jupiter will have risen very close to the lower left of Mars as the planets approach each other for their close conjunction next month.
Gigantic Jupiter rises in the east-southeast about two hours after much dimmer Mars in early December but only a few minutes after Mars at the end of the month. Even small to medium size amateur telescopes will reveal the dynamic cloud filled atmosphere of this enormous planet. The most famous feature in its atmosphere is the Great Red Spot, a massive storm twice the size of Earth that has been studied for about 300 years. The size of this storm has been growing smaller over time.
This month, Saturn is passing behind the sun in relation to Earth and will reappear in the morning sky in January.
The distant planet Uranus lies in the constellation Pisces the Fish. Although it can be spotted without optical aid in dark skies by keen eyed observers, binoculars or a small telescope make the search much easier. It will appear as a tiny, pale, bluish-green featureless disk in a 3-inch telescope.
Remote Neptune can be glimpsed through telescopes against the background stars in the constellation Aquarius. Look for it nearly due south as soon as the sky becomes sufficiently dark following sunset. A telescope will reveal its tiny dim grayish-blue disk. While observing this object, realize that you are seeing another world that lies 2.8 billion miles away.
The Geminid Meteor Shower will peak on the night of December 13/14. Moonlight will not be a limiting factor this year since the slim waning crescent moon will not reflect much light when it rises near 3:30 a.m. Peak activity will occur on the morning of the 14th between midnight and 4 a.m. If the sky is clear, observers at a dark site may witness up to 120 meteors per hour during the peak hours. The Geminids are not superfast meteors but strike Earth’s atmosphere at shallow angles, often producing dramatic fireballs that are really impressive to see.
December’s Full Moon will occur tonight and will be the closest and largest full moon this year. This will be a perfect time to observe the large crater Tycho and its incredible ray system. These long white lines remain from a tremendous impact that occurred when a large object struck the moon well over a million years ago, causing bright lunar soil to be sprayed outward.
The sun will arrive at the December Solstice on Dec. 21 at 11.28 a.m. EST. At that point in time, winter arrives in the Northern Hemisphere and summer begins in the Southern Hemisphere.
Editor’s note: This monthly guide to the stars is from the Marshall Martz Memorial Astronomical Association and The Post-Journal and OBSERVER. For further information, contact the M.M.M.A.A. at martzobservatory.org.