There’s a beautiful encounter in the western sky the next couple of evenings — a conjunction between the Moon and the planet Venus. Venus is the “evening star,” so you just can’t miss it. It stands above the Moon tonight, and about the same distance to the right of the Moon tomorrow night.
The Moon is the barest of crescents tonight. Sunlight will illuminate only a sliver of the lunar hemisphere that faces our way. As the sky darkens, though, you’ll be able to see the dark portion of the Moon, lit up by earthshine — sunlight reflected off of Earth. In fact, if you were on the Moon, you’d see an almost-full Earth hanging in the sky, shining dozens of times brighter than a full Moon.
Venus goes through a cycle of phases, too. Right now, it’s about three-quarters illuminated, which helps make it nice and bright. Venus is too far away to see the phases with the eye alone, or even with most binoculars. But that cycle is an easy target for small telescopes.
Venus emerged from behind the Sun a few months ago, so it was almost full. Now, it’s circling back toward Earth, so we’re starting to see some of its nightside. Over the coming months, the illuminated fraction of the planet will grow smaller as Venus prepares to cross between Earth and the Sun. But Venus will move closer to Earth as that happens. So even though we see less and less of its dayside, Venus will actually shine brighter — enhancing the beauty of the evening star.