Comments on: A Date Idea Analyzed

By: tbabb

tbabb — Fri, 09 Oct 2009 06:47:43 +0000

While on vacation a few weeks ago, I had a thought that led me down a similar line of reasoning:

How “curved” is lake tahoe? I.e., if you set a perfectly flat plane down at lake level on one shore, how far below the plane would the lake be at the opposite shore, 22 miles away, due to the curvature of the earth?

Using similar math, you wind up with somewhat surprising answer: 300 feet. I had to double check that a few times.

By: Hungry_Joe

Hungry_Joe — Thu, 24 Sep 2009 19:45:32 +0000

Much as I hate to burn holes In a beautiful idea, I can see one thing wrong in this logic.

I would consider a sunset not to be a fixed moment in time, but to be the whole duration In which the sun sinks over the horizon. The shortest period of time this could be defined as is from when the lowest part of the sun appears to just touch the horizon (so the horizon appears like a tangent), to when the sun can no longer be seen. A definition of a sunset which would give a longer time would be the period of time when the suns light is refracted so It appears red.

The calculations shown here give the rate of climb that would have to be maintained for the sun to appear in the same position relative to the horizon. For the same sunset to be experienced twice you would have to wait until the sun has sunk, and then elevate yourself at a rate faster than the one given here, until the sun appears right above the horizon again.

This would take a different period of time depending on how long the sun took to set, which is different at all times of the year, (unless you happen to live at the equator).

This is not to say that the answer given by this calculation is useless. When Space Elevators are developed, this is the rate at which they will have to climb for people in them to enjoy a (semi) perpetual sunset. Now I for one think that that is a great date idea.

Yours In Maths
Hungry_Joe

By: gummih

gummih — Thu, 24 Sep 2009 18:10:28 +0000

another interesting stunt would be bungeeshooting right after the sun sets, that way you might get serial sunsets.

By: Brandon

Brandon — Thu, 10 Sep 2009 03:00:01 +0000

I didn’t read all of the comments, but I did note that refraction was also neglected. Just saying.

By: Erich

Erich — Thu, 03 Sep 2009 13:55:10 +0000

Is your line to the top of the sun or the bottom of the sun or the center of the sun, which is 1920 arcseconds (.533 degrees)? It seems your calculations should be based on when the top of the sun is under the horizon, and getting the lift high enough to see the bottom of the sun. This adds non-trivial timing and height requirments.

By: Patanol

Patanol — Sun, 23 Aug 2009 10:35:02 +0000

Patanol…

I don’t do conventions very often but I recently went to ConBust out in Northampton MA while v [...]…

By: Itay

Itay — Fri, 21 Aug 2009 16:06:48 +0000

well don’t you think it much easier just to watch the sunset from a building next to the sea, and the go to the much faster elevator? though it’s much less romantic :)

By: Alan Horkan

Alan Horkan — Thu, 20 Aug 2009 16:42:42 +0000

Rather than using a cherry picker to enjoy a second sunset I believe if you are on a West coast with an ocean you can use the reflection of the sun to get the illusion of a secondary sunset (or one really long slow sunset).

By: Sherwin Arnott

Sherwin Arnott — Wed, 19 Aug 2009 01:45:17 +0000

In your calculations, you have overlooked the refraction of light in our atmosphere. Your model is a reasonable approximation – but I believe that refraction slows the perceived setting of the sun! That is, the lower the sun gets, the greater the refraction and the the longer it remains visible.

So a shorter, slower, more slovenly lift might actually do the trick.

Regrettably, I have not the math skills to quantify this affect.

By: Tom West

Tom West — Mon, 17 Aug 2009 19:36:57 +0000

Cheap version: lie down on the sand, just out of reach of the waves (or just within reach, depending on weather). The nstand up as soon as sunset one has happened. Sunset two follows a few seconds later.