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The dumb questions thread

Why do craters and other depression landforms so often appear to be convex in aerial photos?
 
My guess is the distribution of energy. The crater is deeper in the middle and diminishes by maybe 1/r^2. I think both heat and acoustic energy may diminish 1/r^2. Maybe there is a wiki page on explosive's blast energy.

There are also mushroom clouds.

Bomb craters.
 
steve_bank said:
My guess is the distribution of energy. The crater is deeper in the middle and diminishes by maybe 1/r^2. I think both heat and acoustic energy may diminish 1/r^2. Maybe there is a wiki page on explosive's blast energy.

There are also mushroom clouds.

Bomb craters.
Click to expand...

Well you tried steve_bank. Angry Floof didn't ask why craters had the shape they have. She asked whether the process of photography or some optical illusion inherent in humans perception produce the illusion that the crater is a dome.

From  Crater illusion

The Crater Illusion also known as the Crater/Dome Illusion or Dome Illusion is an optical illusion which causes impact craters in some images to appear as domes or mountains.[1] It is believed to be caused by our being accustomed to seeing light from overhead.[2] When some images are taken from orbit, the light from the sun is nearly horizontal. This is the only time shadows are seen. Our brains are tricked into thinking that the interior of the crater is above the surrounding terrain instead of below it
Click to expand...
 
Well then they appear circular because they are circular...

A high speed abject stinking the moon almost instantaneosly converts kinetic energy to heat and deformation of the surface and ejecting material.

It is spherical because the energy propagates as if originating form a small point radiating in all directions, IOW 1/r^2.

There is a picture of a micro meteorite strike on a space shuttle window. A somewhat spherical hole.

https://www.scienceabc.com/nature/u...-the-moon-round-and-not-some-other-shape.html
 
Steve, her question has nothing to do with the shape of the crater. It has to do with the appearance of the crater.
 
Steve has very poor eyesight. Perhaps he doesn't understand the illusion... or what hylidae means. ;)
 
Thank you for ending my Sunday with a great bug belly ligh.

I will decline an ensuing debate on the appearance of a crater and what it really looks like.
 
Wiploc said:
DBT said:
Nice illusion.
Click to expand...

I agree. They look like plates, but they're really meteor craters.
Click to expand...

:D

fromderinside said:
steve_bank said:
My guess is the distribution of energy. The crater is deeper in the middle and diminishes by maybe 1/r^2. I think both heat and acoustic energy may diminish 1/r^2. Maybe there is a wiki page on explosive's blast energy.

There are also mushroom clouds.

Bomb craters.
Click to expand...

Well you tried steve_bank. Angry Floof didn't ask why craters had the shape they have. She asked whether the process of photography or some optical illusion inherent in humans perception produce the illusion that the crater is a dome.

From  Crater illusion

The Crater Illusion also known as the Crater/Dome Illusion or Dome Illusion is an optical illusion which causes impact craters in some images to appear as domes or mountains.[1] It is believed to be caused by our being accustomed to seeing light from overhead.[2] When some images are taken from orbit, the light from the sun is nearly horizontal. This is the only time shadows are seen. Our brains are tricked into thinking that the interior of the crater is above the surrounding terrain instead of below it
Click to expand...
Click to expand...

Thanks! That makes the most sense. I've seen the plate image (and the dancer image, etc.) and it's easy to "flip" them in my mind when I want to, but aerial images of craters won't cooperate, so I knew there must be some explanation specific to craters' size and/or aerial imagery.
 
If we assume the light is coming from the right, then we are looking down into the plates. But if the light is from the left, then the plates are upside down, protruding up towards us.
 
Wiploc said:
If we assume the light is coming from the right, then we are looking down into the plates. But if the light is from the left, then the plates are upside down, protruding up towards us.
Click to expand...

Yeah, that's what I see when I look at the plates. I can imagine the direction of the light and see them either way. Images of craters don't cooperate, though.
 
Post a link, or an image of an upside down crater, if you would.
 
Here's a picture of a uplifted mountain on Mars, mostly flat on top like an American Southwest mesa:



Victoria-crater-mars-dome.jpg




Actually, no. It's a picture of Victoria Crater, but flipped.




 
Here's another one.

main-qimg-fc5da32af0320bb0c6d4f13446c1e41e.webp
 
Angry Floof said:
Wiploc said:
If we assume the light is coming from the right, then we are looking down into the plates. But if the light is from the left, then the plates are upside down, protruding up towards us.
Click to expand...

Yeah, that's what I see when I look at the plates. I can imagine the direction of the light and see them either way. Images of craters don't cooperate, though.
Click to expand...

I can't make it work with the craters.

For that matter, I can no longer make it work with the plates.
 
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