月球的可见外观并非一成不变，而是随着其围绕地球的轨道运动而周期性变化，这就是月相。月相是一个包含八个独特可见阶段的完整周期，历时约29.5天。这些变化源于太阳光照射到月球不同部分的角度随月球公转而改变。文章详细介绍了当前（9月1日）的月相为“盈凸月”，约62%的月面被照亮，并列举了在不同观测条件下（肉眼、双筒望远镜、望远镜）可观测到的月球表面特征。此外，文章还预告了下一个满月日期（9月7日），并阐述了月相形成的根本原因及其八个主要阶段：新月、盈月初、上弦月、盈凸月、满月、亏凸月、下弦月和亏残月。

🌕 月相周期与成因：月球的可见外观变化是由于其围绕地球公转，导致太阳、月球、地球之间的角度不断变化，从而影响了月球被太阳照亮的区域。整个月相周期约为29.5天，包含八个主要阶段，这使得我们看到的月球形状和亮度随之变化。

🌟 当前月相与观测：截至9月1日，月相为盈凸月，约62%的月面被照亮。文章细致地列出了在不同观测条件下可见的月球表面特征，包括肉眼可见的泰勒斯坑、风暴洋和静海，以及使用双筒望远镜或望远镜能看到的更多细节，如宁静海、冷海、亚平宁山脉、阿波罗11号着陆点、笛卡尔高地和一条长达68英里的月球断层线“直墙”。

📅 未来月相预告与八大阶段详解：文章预告下一个满月将在9月7日出现，并详细解释了月相形成的根本原因——即月球轨道变化导致了我们看到的月面被照亮部分的差异。文章列举并阐述了月相的八个主要阶段：新月（不可见）、盈月初（右侧出现新月形亮区）、上弦月（右半月亮）、盈凸月（超过半月亮）、满月（全月亮）、亏凸月（右侧开始变暗）、下弦月（左半月亮）以及亏残月（左侧出现新月形亮区）。

The moon never looks exactly the same from night to night. Its changing appearance is a result of its journey around Earth. This is called 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 what's happening with the moon tonight, Sept. 1.

What is today’s moon phase?

As of Monday, Sept. 1, the moon phase is Waxing Gibbous, and 62% will be lit up to us on Earth, according to NASA's Daily Moon Observation.

There's lots to see on the moon's surface tonight, so lets get into it. With no visual aids, you'll see the Tycho Crater, the Mare Crisium, and the Mare Tranquillitatis. With binoculars, you'll also get a glimpse of the Mare Nectaris, the Mare Frigoris, and the Apennine Mountains.

If you have a telescope too, you'll see so much more. Enjoy glimpses of the Apollo 11, Descartes Highlands, and the Rupes Recta, a 68-mile-long lunar fault line.

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.