This yr, Christmas Eve will convey a gorgeous sight to the sky shortly after sundown: two brilliant planets sharing the twilight with a skinny crescent Moon.
Look southwest about half-hour after sundown and also you’ll simply spot brilliant Venus (magnitude –3.9) about 5° excessive. Simply 4° to its higher left (east) is Mercury, a dimmer magnitude –0.5. And standing to the planets’ left (east) is a fragile crescent Moon just below 4 % lit, displaying off a mere sliver of its jap limb.
Collectively, the trio create a triangle within the fading twilight that units round 6 P.M. native time. There’s no want for binoculars or a telescope to benefit from the present, although in case you have observing tools accessible, you possibly can examine and distinction the planets’ disks beneath larger magnification because the sky grows darker. Venus is 10″ throughout and almost full, displaying off a 97-percent-lit disk. Mercury seems 7″ huge and is just below half lit, its phase at 49 %. Solely these two planets present phases as a result of they lie nearer to the Solar than Earth.
Solar and Moon on December 24, 2022
Dawn: 7:20 A.M.
Sundown: 4:39 P.M.
Moonrise: 8:56 A.M.
Moonset: 6:03 P.M.
Moon Part: Waxing crescent (3%)
*Instances for dawn, sundown, moonrise, and moonset are given in native time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. native time from the identical location.
Venus now sits about 1.62 astronomical models from Earth, whereas Mercury is 0.92 astronomical models away. (One astronomical unit, or AU, is the common Earth-Solar distance.) Though Mercury orbits nearer to the Solar than Venus, because of the planets’ present places of their orbits, Mercury is nearer to Earth proper now. Nonetheless, Mercury nonetheless seems smaller as a result of it’s lower than half the diameter of Venus, which is roughly Earth’s dimension.
Though nobody may mistake this specific celestial alignment for a “star,” some historians consider that the Star of Bethlehem, related to the primary Christmas, could have been an analogous assembly or conjunction of planets within the sky. And there’s one such conjunction arising: On Wednesday, December 28, Venus and Mercury will stand simply 1.5° aside within the night sky, nonetheless readily seen collectively, whereas the Moon could have moved on into Aquarius. A number of hours later, early on the twenty ninth, Mercury will cross 1.4° due north of Venus, although the 2 will stay beneath the horizon then.
Keep tuned to our Sky This Week column for extra particulars on this occasion and others each day.
