If you had a clear western horizon, you had your shot at this view!
On September 9, 2021, the Moon and Venus nearly overlapped.
The two brightest nighttime objects appeared separated by just 4° in Earth’s post-sunset skies.
The full Moon can shine over 1500 times as bright as Venus, although September 9’s crescent was merely ~10 times as bright.
Most of the Moon remained dark, with Sun-induced shadows highlighting its crater walls.
The Moon’s thin crescent arrived just 2 days after its “new” phase.
Simple geometry sufficiently demonstrates the Sun’s much greater distance than the Moon’s.
Cloud-rich Venus, on the other hand, exhibits different phase properties.
Through binoculars or a telescope, a small gibbous appears: a mostly full Venus.
This demonstrates Venus’s tremendous distance from Earth: comparable to the Sun, not the Moon.
The phases of Venus, throughout the year, reveal the Solar System’s scale.
At a September 9 distance of ~157 million kilometers, Venus was ~400 times the Earth-Moon distance.
However, Venus is 5.4 times as reflective and 12.1 times the area of the Moon.
Its larger intrinsic brightness creates fascinating spectacles alongside the Moon.
From Earth, the Moon and Venus are both night sky objects capable of casting shadows.
Only during lunar eclipses can Venus outshine the Moon.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Starts With A Bang is written by Ethan Siegel, Ph.D., author of Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive.