What's Up in The Sky Now
December 2017 (Notes by DMAS member Dave Lynch)
This month is not a real good month as far as planets go. Other than two far away and dim planets, all of the action will be taking place in the pre-dawn hours.
MERCURY put in a brief appearance last month but once again drops below our line of vision this month. It will appear again in the early morning hours late in December and rapidly climbs high enough to be seen well before sunrise.
VENUS is rising just before the sun comes up and will be hard to see early in the month and impossible to spot only a week later. The glare of the sun and conjunction with the sun on December 9th will completely hide the planet.
EARTH is approaching its deep freeze cycle this month. Even though it means crisper and clearer skies, the temperature makes viewing much more of a hardship than previous month. Dress warm.
MARS has been hanging around low in the sky for months and has finally moved to the early morning hours. Rising about two hours before the sun, Mars and Jupiter are in a close race in the eastern sky in the hours before sunrise.
JUPITER starts the month out trailing Mars in the early morning hours but rapidly catches up to Mars and starts to rise only a couple of minutes after the Red Planet. You won't miss seeing Jupiter as it continues to brighten rapidly all month.
SATURN has finally slipped below the western horizon and will be gone from sight now until late next year.
URANUS is slightly brighter this month at a whopping 6th magnitude. Cruising through Pisces it will remain visible most of the night finally setting about two hours before sunrise.
NEPTUNE is slightly dimmer than Uranus at only 8th magnitude and moving out ahead by several hours. Look quickly as Neptune will drop out of sight right around midnight this month.
Full Moon -> December 03
Last Quarter -> December 10
New Moon -> December 18
First Quarter -> December 26
A Comet Approaches
Since we have a shortage of planets to look at this month try your luck with a visitor from the edge of the solar system this month. Comet C/2016R2 (Who comes up with these names?) will cruise through the Constellation of Orion in December. Although it will not come all that close to the sun and brighten up very much, the "experts" predict that this ice ball will be fairly bright and is expected to eject its surface layers of gas water ice and dust at a higher than normal rate. Because of its slow rate of speed by staying out from the sun, this comet is predicted to hang around for as long as six months or more.
Speaking of comets:
A recent study has found that as many as 100 stars make very close passes to the Oort Cloud which surrounds our solar system possibly upsetting and disturbing the clusters of comets. The measurement of one star in particular, Gliese 710, places its closest approach to the Oort Cloud at only 16,000 Astronomical Units. It is estimated that this close approach could increase the number of comets entering our solar system by a factor of 100 of which 10% might run into something. In the far distant past as our solar system was forming, it has been theorized that the water on Earth came from some heavy bombardment of comets. Not to sound like Chicken Little but lets hope this doesn't happen again.