<p>Actually, most of the surface of the Moon is covered with craters like that. The exception are the large dark 'seas', which are in fact <a href="https://en.wikipedia.org/wiki/Lunar_mare" rel="noreferrer">basaltic plains</a>. The seas are mostly present on this side of the moon; the far side of the moon is <a href="https://en.wikipedia.org/wiki/Moon#/media/File:Moon_Farside_LRO.jpg" rel="noreferrer">almost entirely composed of craters</a>.</p>

<p>The reason you see a ring near the <a href="https://en.wikipedia.org/wiki/Terminator_(solar)#Lunar_terminator" rel="noreferrer">terminator</a> (the boundary between the illuminated and dark part) is that the shadows make the craters much more visible.</p>

<blockquote>
  <p>Due to the angle at which sunlight strikes this portion of the Moon, shadows cast by craters and other geological features are elongated, thereby making such features more apparent to the observer. This phenomenon is similar to the lengthening of shadows on Earth when the Sun is low in the sky.</p>
</blockquote>

CC BY-SA 4.0
2019-05-26T22:32:03.720Z
Exactly. When observing the half-moon in a telescope, craters are easily visible near the terminator. They are much less visible far from the terminator, on both sides. You need long shadows to make visible features such as craters, mountains, etc.
Florin Andrei
CC BY-SA 4.0
2019-05-28T13:52:26.463Z
The illlumination of the Moon in that image is very weird -- if the terminator is down the middle, then what is the highlight on the far left margin, making it look close to new at first glance? Seems some pretty heavy contrast adjustments have been made in postprocessing.
hmakholm left over Monica
CC BY-SA 4.0
2019-05-28T14:41:40.227Z
@HenningMakholm There is most definitely some significant post-processing at work here. In addition to the tweaked contrast between the dark and light sides, the background stars are too visible, and the "halo" looks... odd.
Mike Harris
CC BY-SA 4.0
2019-05-26T18:32:12.623Z
2019-05-26T18:32:12.623Z
Glorfindel
<p>I saw this picture on the <a href="https://www.bbc.com/news/world-us-canada-48407023" rel="noreferrer">BBC news website</a>.</p>

<p><a href="https://i.sstatic.net/UZEeR.png" rel="noreferrer"><img src="https://i.sstatic.net/UZEeR.png" alt="enter image description here"></a></p>

<p>There appears to be a ring of craters in the center of the picture, aligned in an approximate sub vertical orientation.</p>

<p>Am I just seeing things or does this apparent ring of craters a feature and does it extend to the far side of the moon? If it does exist, what form of bombardment or gravitational attraction would have create such a ring?</p>

<the-moon><crater>
Apparent Ring of Craters on the Moon
Fred
# Apparent Ring of Craters on the Moon

(Asked by: username_0 on 2019-05-26)

I saw this picture on the [BBC news website](https://www.bbc.com/news/world-us-canada-48407023).

[![enter image description here](https://i.sstatic.net/UZEeR.png)](https://i.sstatic.net/UZEeR.png)

There appears to be a ring of craters in the center of the picture, aligned in an approximate sub vertical orientation.

Am I just seeing things or does this apparent ring of craters a feature and does it extend to the far side of the moon? If it does exist, what form of bombardment or gravitational attraction would have create such a ring?

**Tags:** the-moon, crater


---

## 1 answers

### Answer by username_1 on 2019-05-26. Score: 45 | Accepted answer

Actually, most of the surface of the Moon is covered with craters like that. The exception are the large dark 'seas', which are in fact [basaltic plains](https://en.wikipedia.org/wiki/Lunar_mare). The seas are mostly present on this side of the moon; the far side of the moon is [almost entirely composed of craters](https://en.wikipedia.org/wiki/Moon#/media/File:Moon_Farside_LRO.jpg).

The reason you see a ring near the [terminator](https://en.wikipedia.org/wiki/Terminator_(solar)#Lunar_terminator) (the boundary between the illuminated and dark part) is that the shadows make the craters much more visible.

> Due to the angle at which sunlight strikes this portion of the Moon, shadows cast by craters and other geological features are elongated, thereby making such features more apparent to the observer. This phenomenon is similar to the lengthening of shadows on Earth when the Sun is low in the sky.

> **Comments:**
> **username_2**: Exactly. When observing the half-moon in a telescope, craters are easily visible near the terminator. They are much less visible far from the terminator, on both sides. You need long shadows to make visible features such as craters, mountains, etc.  
> **username_3**: The illlumination of the Moon in that image is very weird -- if the terminator is down the middle, then what is the highlight on the far left margin, making it look close to new at first glance? Seems some pretty heavy contrast adjustments have been made in postprocessing.  
> **username_4**: @HenningMakholm There is most definitely some significant post-processing at work here. In addition to the tweaked contrast between the dark and light sides, the background stars are too visible, and the "halo" looks... odd.  

---

