Meteor shower features gems of sky
The Geminid meteor shower (radiant in the constellation of Gemini — the Twins) is one of the year's most anticipated meteor showers.
The shower peaks overnight on Dec. 13-14, starting just as the eastern sky darkens around 6:30 p.m. Dec. 13, with the most meteors likely to be seen between 2 a.m. and dawn on Dec. 14, when the radiant is at its highest elevation in the night sky (about halfway from the horizon to the zenith).
The Geminids (or Gems, as they are affectionately called) are unique; they are the only meteor shower associated with an asteroid rather than a comet. It wasn't until after the asteroid 3200 Phaethon was discovered on Oct. 11, 1983, that the Gems were associated with this asteroid.
Phaethon, an Apollo-class asteroid, is listed as an active asteroid, meaning that, although technically an asteroid, it demonstrates a cometlike characteristic of ejecting dust particles from its surface as it nears the sun.
Phaethon has a 1.434-year (523.6 days) orbital period. The Gems peak coincides with the new moon on Dec. 14, so there will be no interfering moonlight. Expect to see anywhere from over 50 per hour to more than 150 per hour of these bright, slow-moving, colourful meteors; the further you are away from urban lights, the more meteors you will observe.
Dress warmly (coat, warm boots, hat, gloves, scarf, etc), find a comfortable chair or lounge chair (the best idea), blankets or sleeping bags and have something warm to drink on hand. Let your eyes adjust to the dark for 15-20 minutes, place the northeast behind you and settle in for the show.
If the weather forecast for Dec. 13-14 is predicting clouds, try the night of Dec. 12-13 or the nights of Dec. 14-15 or Dec. 15-16. The Gems are around until Dec. 16 (though in lesser
numbers). Enjoy!
OTHER GEMS OF THE SKY
While Dec. 1 marked the start of meteorological winter (based on the division of the year into four, three-month sections), the majority of us hold our collective breathes for the official start of winter on Dec. 21 (astronomical winter).
Overhead, the stars bear silent witness to humankind's preoccupation with time and the turning seasons, oblivious to the fact that it is, from the audience seats of our planet, their nightly performances that we so eagerly await. Quiet now, please, ladies and gentlemen, the play is about to start.
As the setting sun dims the celestial theatre lights to darkness, the actors begin to present themselves on stage. First to appear, in the opening acts of our winter's play, are Prince Perseus and his princess bride Andromeda, as well as the vain Queen Cassiopeia, the ram Aries, and the silvery fishes of Pisces.
Waiting in the sky's eastern wings for their cue to stride on stage as the play progresses
towards midnight is the bold hunter, Orion and his canine companions, the fierce bull Taurus, the renowned charioteer Auriga, and the tragic Gemini twins Castor and Pollux.
As befits divas, these actors are all prominently bedecked with some of the night sky's brightest and most colourful celestial jewels: Betelgeuse, Rigel, Aldebaran, Capella, Procyon, and the night's brightest and most renowned jewel, Sirius.
Once they have beguiled us with their harrowing adventures and tragic tales of love and sacrifice (on occasion bringing us to tears), they take their bows and, to our boisterous applause, make a quiet exit stage right as the sky's house lights are once again slowly raised in the east.
Begrudge them not their rest, for they will return each night throughout the winter season. Weather permitting, you shall have ample opportunity to assess their acting skills and may well have occasion to yell, "Bravo!"
THIS WEEK’S SKY
Mercury, heading toward solar conjunction on Dec. 19,
is too close to the sun to be observed.
Venus (magnitude -3.96) is briefly visible in the eastern pre-dawn sky, rising around 5:25 a.m., reaching an altitude of 15 degrees above the southeast horizon before fading from view around 7:20 a.m.
Mars (magnitude -0.91) is visible in the evening sky 31 degrees above the southeast horizon around 4:50 p.m., reaching its highest point in the early evening sky 51 degrees above the southern horizon; it is observable until about 2 a.m., at which time it drops below eight degrees above the western horizon.
Jupiter (magnitude -2.02) and Saturn (magnitude +0.64) are both visible in the early evening southwest, 18 degrees and 17 degrees respectively above the horizon, Jupiter by 4:50 p.m. and Saturn by 5:10 p.m.; Jupiter sets around 7:30 p.m, followed by Saturn around 7:40 p.m.
As mentioned last week, the year's final (at least to date) comet is Comet Erasmus. Currently in the constellation of Libra — the Balance/Scales (in the eastern, pre-dawn sky around 6 a.m.), the comet
shines at magnitude 7.5 (visible in binoculars). Brightening daily, Erasmus is expected to reach magnitude 5.8 and naked-eye visibility by Dec. 11. To follow this comet, go to Comet C/2020 S3 (Erasmus) information at TheSkyLive.com
As much as I would like to claim the error was intentional to see if anyone was reading my articles, the truth is, I made a mistake. In my Nov. 23 column regarding Saturn's rings, I erroneously stated that the depth of the rings was up to 200 km, when, in fact, I had meant to say 200 meters. Thanks to the sharp eyes of one of my readers, my error was discovered. Tip of my celestial hat to Pat D'Entremont.
Until next week, clear skies.
EVENTS
• Dec. 7 — Last quarter moon
• Dec. 12 — Moon at perigee (closest to Earth)
• Dec. 13 — Geminid meteor shower peak (overnight)
Glenn K. Roberts lives in Stratford, P.E.I., and has been an avid amateur astronomer since he was a small child. His column, Atlantic Skies, appears every two weeks.