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#1 2009-02-21 23:21:39
- Ninja 101
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- Registered: 2006-02-20
- Posts: 936
Calculate your personal horizon.
I recently came across the equation:
d=√1½h
(Where d is distance and h is your height)
So the distance that you can see is the square-root of one-and-a-half times your height, so a 6ft person can see 3 miles. Good, eh?
Chaos is found in greatest abundance wherever order is being saught. It always defeats order, because it is better organized.
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#2 2009-02-22 01:12:18
- JaneFairfax
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- Registered: 2007-02-23
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Re: Calculate your personal horizon.
Last edited by JaneFairfax (2009-02-22 03:56:52)
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#3 2009-02-22 08:26:47
- MathsIsFun
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- Registered: 2005-01-21
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Re: Calculate your personal horizon.
Jane! Not so extreme please!
Maybe Ninja's formula is a good approximation within the bounds of human height. 6ft->3 Miles is very similar to 2m->5km
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
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#4 2009-02-22 09:03:47
- Ninja 101
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Re: Calculate your personal horizon.
Approximately, I should have written...
Chaos is found in greatest abundance wherever order is being saught. It always defeats order, because it is better organized.
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#5 2009-02-22 10:58:34
- mathsyperson
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- Registered: 2005-06-22
- Posts: 4,900
Re: Calculate your personal horizon.
That formula came up on QI last Friday, and they're generally very good at checking their facts.
Why did the vector cross the road?
It wanted to be normal.
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#6 2009-02-22 11:07:41
- JaneFairfax
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- Registered: 2007-02-23
- Posts: 6,868
Re: Calculate your personal horizon.
So Ninja 101 lives in the UK. 
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#7 2009-02-23 04:13:56
- Ninja 101
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- Registered: 2006-02-20
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Re: Calculate your personal horizon.
Excellent deduction! ^^
Chaos is found in greatest abundance wherever order is being saught. It always defeats order, because it is better organized.
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#8 2009-02-23 12:51:52
- MathsIsFun
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Re: Calculate your personal horizon.
Which is all Quite Interesting ...
"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman
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#9 2009-02-23 16:25:42
- Jai Ganesh
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- Registered: 2005-06-28
- Posts: 48,385
Re: Calculate your personal horizon.
If that includes a myopic, thats fine 
It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.
Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.
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#10 2009-06-02 04:21:38
- JaneFairfax
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- Registered: 2007-02-23
- Posts: 6,868
Re: Calculate your personal horizon.
Someone has uploaded that particular episode of QI on YouTube:
[align=center]http://www.youtube.com/watch?v=RV7-jh_Ya9Q[/align]
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#11 2009-06-02 17:08:52
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Calculate your personal horizon.
Jane is back!!!!!
Thanks for the link.
I might be wrong but Ninja 101's formula is line of sight while Jane's is arc length (along the curved surface of the earth).
http://en.wikipedia.org/wiki/Horizon
According to the above page when R>>h they should be close.
Last edited by bobbym (2009-06-02 17:23:46)
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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