After sunset these next several evenings – June 14, 15 and 16, 2018 – watch for the young waxing crescent moon to swing by Earth’s two inferior planets, Mercury and Venus. On all of these evenings, it’ll be easy to see Venus shortly after sundown. After all, Venus is the brightest planet and the second-brightest celestial object in the night sky, after the moon. It’ll take a more heroic effort to spot Mercury beneath Venus. As for the moon, it’ll be tough to see – but possible – on June 14. And on June 15 and 16, the moon will be easy! All in all, we’re due for some very beautiful scenes in the evening twilight. Watch all three evenings … and get a sense for the moon’s movement in orbit around Earth.
Especially if you want to see Mercury – and the young, pale, whisker-thin crescent moon on June 14 – find an unobstructed horizon in the direction of sunset. You may need binoculars to spot the moon and/or Mercury in the glare of evening twilight.
Note added June 14: We received many photos of Thursday evening’s moon, plus the video below from our friend Steven A. Sweet of Lunar 101-Moon Book. Isn’t it cool? Click here to see more photos of the June 14 young moon.
The setting time for the sun, moon, Mercury and Venus varies around the world. On June 14, at middle North American latitudes, the moon and Mercury set close to one hour after sunset, and Venus about 2 1/2 hours after sundown. Click here for a recommended sky almanac that’ll provide you with precise setting times of these worlds in your sky.
After June 14, each following evening, the moon will appear as a wider crescent that’ll be higher up at sunset and stay out longer after dark. Try also to view the earthshine softly illuminating the dark (nighttime) side of the moon, with either the unaided eye or binoculars.
Earthshine is twice-reflected sunlight, with our planet Earth reflecting sunlight to the moon, and the moon, in turn, reflecting sunlight back to Earth.
You know how the late afternoon sun sinks downward in the western sky? Celestial objects seen after dark can also be seen to sink downward to that western horizon, as evening deepens. This apparent westward movement of celestial bodies – sun, moon, planets or stars – is really a reflection of the Earth spinning on its rotational axis from west to east. Earth’s spin makes it appear as if all these celestial bodies are moving westward while the Earth remains still. We can’t feel Earth’s spin, but, as these sky bodies testify, we know it’s there.
Meanwhile, if you watch on several evenings, at just the same time, you’ll note the moon’s movement upward from the western horizon. Each evening, the moon will be farther east on the sky’s dome than it was the day before. This eastward shift of the moon on our sky’s dome is a reflection of the moon’s eastward motion in orbit around Earth.
So watch as a great drama of sky motions unfolds in the west at dusk, as the moon sweeps by the two planets, Mercury and Venus, in mid-June 2018!
Bottom line: On June 14, 15 and 16, 2018, the young moon swings by two planets in the western sky after sunset. They are Mercury and Venus.