The moon is slowly disappearing from view, and that's because of where we are in the lunar cycle. What's the lunar cycle, you ask? The lunar cycle is a series of eight unique phases of the moon's visibility. The whole cycle takes about 29.5 days, according to NASA, and these different phases happen as the Sun lights up different parts of the moon whilst it orbits Earth.
So let's see what's happening with the moon tonight, Aug. 17.
What is today’s moon phase?
As of Sunday, Aug. 17, the moon phase is Waning Crescent, and it is 35% lit up to us on Earth, according to NASA's Daily Moon Observation.
We're on day 24 of the lunar cycle, so that means for the next few days it'll be less and less visible, until there's nothing to see at all. But for now, there's still plenty to spot on the moon's surface. With just your naked eye, catch a glimpse of the Aristarchus Plateau and the Copernicus Crater.
With binoculars, see even more, including the Grimaldi Basin and the Gassendi Crater. Telescopes truly come into their own for moon gazing, and tonight with one, you'll see the Reiner Gamma and the Schiller Crater, too.
When is the next full moon?
The next full moon will be on Sept. 7. The last full moon was on Aug. 9.
What are moon phases?
According to NASA, moon phases are caused by the 29.5-day cycle of the moon’s orbit, which changes the angles between the Sun, Moon, and Earth. Moon phases are how the moon looks from Earth as it goes around us. We always see the same side of the moon, but how much of it is lit up by the Sun changes depending on where it is in its orbit. This is how we get full moons, half moons, and moons that appear completely invisible. There are eight main moon phases, and they follow a repeating cycle:
New Moon - The moon is between Earth and the sun, so the side we see is dark (in other words, it's invisible to the eye).
Waxing Crescent - A small sliver of light appears on the right side (Northern Hemisphere).
First Quarter - Half of the moon is lit on the right side. It looks like a half-moon.
Waxing Gibbous - More than half is lit up, but it’s not quite full yet.
Full Moon - The whole face of the moon is illuminated and fully visible.
Waning Gibbous - The moon starts losing light on the right side.
Last Quarter (or Third Quarter) - Another half-moon, but now the left side is lit.
Waning Crescent - A thin sliver of light remains on the left side before going dark again.
