As of Saturday, Sept. 12, NASA’s Daily Moon Guide tracker reports that the Moon is in the Waxing Crescent phase with 2% of its surface visible, marking the start of a fresh lunar cycle leading toward the next Full Moon on September 26, according to NASA. Stargazers watching the night sky will notice the lunar disk growing larger over the coming nights as the Moon progresses through its orbit around Earth.
How the Lunar Cycle Works
According to NASA, the Moon’s appearance shifts over a period of roughly 29.5 days as it orbits Earth. This cycle, also known as a lunation or synodic month, averages 29.53059 days according to Almanac.com data. The changing phases depend on the relative positions of the Earth, Moon, and Sun, dictating how much of the Moon’s sunlit side faces human observers on Earth. Because the Moon produces no light of its own, according to Almanac.com, observers only see sunlight reflecting off the lunar surface.
The Eight Distinct Moon Phases
Astronomers divide the lunar cycle into four primary phases and four secondary phases. According to Almanac.com, primary phases occur at a specific moment globally, while secondary phases represent transitional spans of time. The complete sequence breaks down into:
- New Moon: The Moon positions itself between Earth and the sun, rendering the visible side dark and invisible to the naked eye, according to NASA. Almanac.com notes this conjunction places the Sun and Moon closest together on the same side of Earth.
- Waxing Crescent: A small sliver of light appears on the right side in the Northern Hemisphere, expanding daily until the next primary phase.
- First Quarter: Exactly half of the Moon is illuminated on the right side in the Northern Hemisphere. Almanac.com explains that the Moon has completed one-quarter of its orbit at this point, placing it 90 degrees east of the Sun.
- Waxing Gibbous: More than half of the lunar surface is lit up as the Moon approaches full illumination.
- Full Moon: The entire face of the Moon is illuminated and fully visible from Earth.
- Waning Gibbous: The Moon begins losing light on the right side in the Northern Hemisphere after passing its peak.
- Third Quarter (Last Quarter): Another half-Moon phase, though illumination now appears on the left side in the Northern Hemisphere.
- Waning Crescent: A thin sliver of light remains on the left side before the lunar cycle resets to darkness.
Did you know? While primary Moon phases happen at an exact astronomical moment everywhere on Earth, your local time zone determines what hour you actually see it—and whether the Moon has risen above your local horizon yet, according to Almanac.com.
Frequently Asked Questions
What is the Moon phase today?
According to NASA’s Daily Moon Guide for Saturday, Sept. 12, the Moon is in a Waxing Crescent phase with 2% of its surface visible.
When is the next Full Moon?
The next Full Moon will occur on September 26, according to NASA trackers.
How long does a complete lunar cycle take?
A full lunar cycle takes roughly 29.5 days, with Almanac.com noting an average duration of 29.53059 days.
Why does the Moon change shape?
The Moon’s appearance changes based on its orbital position relative to Earth and the Sun, which alters the angle of sunlight reflecting off its surface toward human eyes, according to NASA and Almanac.com.
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