<p>That is the rebound effect. Just like a rock falling into a pond causes a big ripple and a big drop to jump out in the center, the same happens with a rock striking the Moon.</p>

<p>Refer to <a href="https://physics.stackexchange.com/questions/26091/how-does-the-central-peak-in-moon-craters-form">this</a> astrophysics stackexchange for more information.</p>

CC BY-SA 4.0
2018-09-30T05:25:13.150Z
Great analogy but rofl that name dude- planning any trips to Uranus to destroy it too?
Magic Octopus Urn
CC BY-SA 4.0
2018-09-30T08:40:40.323Z
@MagicOctopusUrn best. lmaoing. comment. ever.
Helen
CC BY-SA 4.0
2018-09-29T23:43:05.890Z
2018-09-29T23:43:05.890Z
User24373
<p>Nice picture! Those peaks are actually a very common feature in craters formed by large impacts. Craters with these features are known as "<a href="https://en.wikipedia.org/wiki/Complex_crater" rel="noreferrer">complex craters</a>". Basically what happens is that when the meteor hits, it pushes in the surface. Then the underlying mantle produces an "elastic rebound" and pushes outwards. This is a similar effect to what happens when you hit a drum. Your drumstick rebounds off the drum, and the drum begins to vibrate. Since rock (even molten rock) is much more dense than a drumskin, it does not vibrate very much. The vibrations solidify, resulting in a crater with one central peak.</p>

<p>How exactly this happens is still being investigated. <a href="http://www.planetary.brown.edu/pdfs/4779.pdf" rel="noreferrer">This paper</a> provides a pretty good explanation of what happens, but it's quite technical.</p>

<p><a href="https://i.sstatic.net/kj4cR.png" rel="noreferrer"><img src="https://i.sstatic.net/kj4cR.png" alt="enter image description here"></a></p>

<p>Even larger impacts will produce <a href="https://en.wikipedia.org/wiki/Peak_ring_(crater)" rel="noreferrer">ring structures</a>. These are relatively rare on the Earth, since such structures are quickly weathered away. A good example of this is the Chicxulub crater off the Yucatan peninsula (the impact that killed the dinosaurs).</p>

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

CC BY-SA 4.0
2018-09-30T05:04:31.563Z
Thanks for the extremely comprehensive answer. Is there a certain size class of asteroid where these would be more common? I dont usually see these on the smaller craters- assuming because it sidnt get deep enough to deform the required mantle layer? So I guess the question would be how thick is the crust usually on the moon?
Magic Octopus Urn
CC BY-SA 4.0
2018-09-30T05:17:59.853Z
@MagicOctopusUrn Unfortunately, I do not know what the cutoff is. But I know that it depends on both the size of the impactor and the structure of the crust and mantle. A more fluid crust and mantle would be more elastic, and a larger impactor would provide more energy.
Phiteros
CC BY-SA 4.0
2018-09-30T05:24:03.397Z
Haha given the bumpy and chaotic gravitational field of the moon knowing the average crust depth would be a chore Im sure- thanks for the clarification regardless.
Magic Octopus Urn
CC BY-SA 4.0
2018-09-30T00:29:50.910Z
2018-09-30T00:29:50.910Z
Phiteros
<p>Was taking some extremely amatuer pictures of the moon from my cheap telescope with my camera phone...</p>

<p><img src="https://i.sstatic.net/MK4rt.jpg" alt="enter image description here"></p>

<p>You see the crater Im talking about? Top right.The one with a little nub in the middle- which Im sure is actually massive. How was this formed differently than the other craters? What couldve caused the hill? </p>

<the-moon><crater>
What are the craters on the moon with peaks in the middle of them?
Magic Octopus Urn
# What are the craters on the moon with peaks in the middle of them?

(Asked by: username_0 on 2018-09-29)

Was taking some extremely amatuer pictures of the moon from my cheap telescope with my camera phone...

![enter image description here](https://i.sstatic.net/MK4rt.jpg)

You see the crater Im talking about? Top right.The one with a little nub in the middle- which Im sure is actually massive. How was this formed differently than the other craters? What couldve caused the hill?

**Tags:** the-moon, crater

---

## 2 answers

### Answer by username_3 on 2018-09-30. Score: 5 | Accepted answer

Nice picture! Those peaks are actually a very common feature in craters formed by large impacts. Craters with these features are known as "[complex craters](https://en.wikipedia.org/wiki/Complex_crater)". Basically what happens is that when the meteor hits, it pushes in the surface. Then the underlying mantle produces an "elastic rebound" and pushes outwards. This is a similar effect to what happens when you hit a drum. Your drumstick rebounds off the drum, and the drum begins to vibrate. Since rock (even molten rock) is much more dense than a drumskin, it does not vibrate very much. The vibrations solidify, resulting in a crater with one central peak.

How exactly this happens is still being investigated. [This paper](http://www.planetary.brown.edu/pdfs/4779.pdf) provides a pretty good explanation of what happens, but it's quite technical.

[![enter image description here](https://i.sstatic.net/kj4cR.png)](https://i.sstatic.net/kj4cR.png)

Even larger impacts will produce [ring structures](https://en.wikipedia.org/wiki/Peak_ring_(crater)). These are relatively rare on the Earth, since such structures are quickly weathered away. A good example of this is the Chicxulub crater off the Yucatan peninsula (the impact that killed the dinosaurs).

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

> **Comments:**
> **username_0**: Thanks for the extremely comprehensive answer. Is there a certain size class of asteroid where these would be more common? I dont usually see these on the smaller craters- assuming because it sidnt get deep enough to deform the required mantle layer? So I guess the question would be how thick is the crust usually on the moon?  
> **username_3**: @MagicOctopusUrn Unfortunately, I do not know what the cutoff is. But I know that it depends on both the size of the impactor and the structure of the crust and mantle. A more fluid crust and mantle would be more elastic, and a larger impactor would provide more energy.  
> **username_0**: Haha given the bumpy and chaotic gravitational field of the moon knowing the average crust depth would be a chore Im sure- thanks for the clarification regardless.  

---

### Answer by username_1 on 2018-09-29. Score: 4

That is the rebound effect. Just like a rock falling into a pond causes a big ripple and a big drop to jump out in the center, the same happens with a rock striking the Moon.

Refer to [this](https://physics.stackexchange.com/questions/26091/how-does-the-central-peak-in-moon-craters-form) astrophysics stackexchange for more information.

> **Comments:**
> **username_0**: Great analogy but rofl that name dude- planning any trips to Uranus to destroy it too?  
> **username_2**: @MagicOctopusUrn best. lmaoing. comment. ever.  

---

