月相是月球围绕地球公转过程中，受太阳光照射而呈现出的不同可见形态。整个月球周期约为29.5天，由八个独特的月相组成。随着月球在轨道上的位置变化，太阳、月球和地球之间的角度随之改变，导致我们从地球上看到的月球被照亮的部分也不同。这解释了为何月亮每晚看起来略有差异，从不可见的“新月”到完全明亮的“满月”，再到逐渐变暗的“残月”。了解月相有助于我们更好地认识宇宙的规律性变化。

🌕 月相的形成源于月球绕地球的29.5天周期性公转，此过程中太阳、月球与地球三者相对角度的变化导致月球被照亮的部分在地球上呈现出不同的可见形态。我们总是看到月球的同一面，但其被阳光照亮程度会根据其轨道位置而改变。

🔭 月球周期包含八个主要阶段：新月（月面黑暗不可见）、蛾眉月（右侧出现一小片光）、上弦月（右侧半月可见）、盈凸月（超过半月被照亮但未满）、满月（整个月面被照亮）、亏凸月（右侧开始失去光）、下弦月（左侧半月可见）以及残月（左侧出现一小片光，随后再次变暗）。

✨ 在特定的日期，如8月2日，月相为盈凸月，月球表面约有60%被照亮。此时，肉眼可见月海（如丰饶海、静海、危机海），双筒望远镜可观测到山脉（如阿尔卑斯山脉、亚平宁山脉）和陨石坑（如普林尼环形山），而通过望远镜则能看到更精细的地貌，如月谷、德卡特高地和阿尔泰峭壁。

🗓️ 下一个满月将出现在8月9日，而上一个满月则是在7月10日。月相的规律性变化是天文学中的一个基本概念，有助于我们理解和预测月球在天空中的可见状态。

Ever wondered why the moon looks slightly different every night? This is to do with the lunar cycle.

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 where we are in the cycle tonight, Aug. 2.

What is today’s moon phase?

As of Saturday, Aug. 2, the moon phase is Waxing Gibbous. According to NASA's Daily Moon Observation, the moon will be 60% lit up tonight.

It's day nine of the lunar cycle, and there's a whole lot for us to see on the moon's surface.

With the unaided eye, enjoy a glimpse of the Mare Fecunditatis, the Mare Tranquillitatis, and the Mare Crisium. If you're in the Northern Hemisphere, look to the top right. If you're in the Southern Hemisphere, you'll see these on the bottom left.

With binoculars, enjoy a glimpse of the Alps Mountains, Apennine Mountains, and the Aphonsus Crater. With a telescope, you can also see the Rima Arladaeus, the Descartes Highlands, and Rupes Altai.

When is the next full moon?

The next full moon will be on August 9. The last full moon was on July 10.

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.