UKC

Maybe the title should read geometry in the mountains....

Anyhow. You get to the top of a mountain with two summits and look at the view. It's disappointing to see that the other summit looks higher.... so you walk over there and look back at the first summit you were on, and it now looks higher?!

This has happened to me two or three times in my life on mountains without good surveys or mapping. I have an idea about what might be going on geometrically, but would be interested to hear other opinions.

In reply to Andes:

what's your idea?

In reply to Andes:

Psychologically I have no idea why the other one always looks higher.

But I reckon if you get down to ground level and line up the two tops and the result is above the horizon then the other one is higher.

In reply to Andes:
There was a Scandinavian physicist called Asbjorsen who studied this. He experimented with goats and measured the heights of their horns on summits.
I think his conclusion was that the grass is always greener on the other summit?

In reply to Dave the Rave:

The other thing is you have to discount the places where perspective causes optical illusions and you think down hill is up hill and vice versa. (e.g. The Silver Band road in the Eden Valley)

In reply to Andes:

Opens post
Reads post
Scratches head
Looks puzzled
Quietly leaves before anyone notices

In reply to Andes:

https://en.wikipedia.org/wiki/Psychophysics
?

In reply to Andes:

It's like a bouncy castle. You cause the other side to rise with your weight sinking into the summit you are on.

In reply to Andes:

Your line of sight to your reference point, which is probably the far horizon beyond the other summit, slopes downward in relation to a line tangential to the earth's surface at your position. The other summit of similar height is always above the line that is your reference and therefore appears, incorrectly, significantly higher than your position.

(However, if you were able to readjust your reference to the true tangent to the earth's surface at your presernt position the other summit would appear lower but this would not be correct either.)

The way that our brains selects reference points for these judgements makes them difficult to get right.

In reply to Jim Fraser:

I'm sure that's at least part of the the story - our brains probably use multiple cues to make this judgement, and can easily get it (slightly) wrong.

Another hill-related misperception is judging the angle of a slope seen straight on - it often appears much steeper than it really is.

In reply to Andes:
What is happening is that the mountains are normally the same height, but are mounted on an extremely sensitive balance. The extra weight of a climber pushes the mountain down a bit, and lifts up the one you are looking at.

You can test this by climbing one of the mountains then having a larger group of friends climb the other one. You will observe the hill dipping slightly as you are lifted a few m higher into the air.

[edit] ultrabumbly did it better.

In reply to Andes:

THis thread has blown my mind completely. As I understand it, some contributiors are claiming that the Earth is NOT FLAT?

In reply to Rigid Raider:

Indeed not. It has mountains on it.