It’s another moon phase tonight, which means the moon will look around half full (or, half gone?). But what phase is it, and what does it mean? Let’s find out.
What is today’s moon phase?
As of Monday, Oct. 13, the moon[1] phase is Third Quarter. Tonight, only 53% will be lit up, according to NASA’s Daily Moon Observation[2].
Third Quarter is also known as the Last Quarter. This occurs when then there is half a moon, but the left side is lit. First Quarter occurs when the right side is lit.
There’s plenty to see on the moon’s surface tonight, even with half of the moon in darkness. With just your naked eye, enjoy a glimpse of the Mare Imbrium, Aristarchus Plateau, and the Kepler Crater. If you want to take your moon gazing a bit more seriously, take out a pair of binoculars. With these, you’ll see even more, including the Clavius and Alphonsus Craters and the Mare Humorum. And if you’re lucky enough to have a telescope, you’ll see all this plus the Apollo 14 and 15 landing spots, and the Reiner Gamma[3], a lunar swirl on the moon’s surface.
When is the next full moon?
The next full moon will be on Nov. 5.
What are moon phases?
Moon phases are a cycle that occur every 29.5 days, as the moon travels around Earth. The changes happen because the Sun, Earth, and Moon are always moving relative to each other. From here on Earth, the Moon can look full, partly lit, or even completely dark, but we always see the same side. What’s different each night is how much sunlight is hitting it.
The eight main moon phases are:
Mashable Light Speed
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. (Northern Hemisphere)
Third Quarter (or Last 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.
References
- ^ moon (mashable.com)
- ^ (opens in a new window) (moon.nasa.gov)
- ^ (opens in a new window) (moon.nasa.gov)