Questions of Latitude: Can You See the Back of Your Head?

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SUMMARY

This discussion centers on the geometric implications of latitude lines as one approaches the North Pole. It establishes that as a person nears the North Pole, the distance to circumnavigate the Earth along latitude lines decreases significantly. The main question posed is whether a person standing one mile from the North Pole at approximately 89.999999 degrees N can see the back of their own head. The consensus is that this is not possible due to the straight nature of line of sight, which does not curve with the latitude line.

PREREQUISITES
  • Understanding of Earth's spherical geometry
  • Familiarity with latitude and longitude concepts
  • Basic knowledge of light behavior and line of sight
  • Awareness of gravitational effects near massive objects, such as black holes
NEXT STEPS
  • Research the mathematical principles of spherical geometry
  • Explore the concept of light bending around massive objects, particularly black holes
  • Study the implications of latitude and longitude in navigation
  • Investigate the effects of curvature on line of sight in various geographical contexts
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Geographers, physicists, educators, and anyone interested in the mathematical and physical properties of Earth's geometry and light behavior.

Ulnarian
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So I got to thinking about lines of latitude recently.

Since the Earth is a sphere, that means that, at the equator, a person would have to walk pretty far to go all the way around the Earth.

Now, as you head towards the North Pole, if you keep walking along the lines of latitude, you will find that your distance traveled to circumnavigate the Earth becomes shorter and shorter as you approach the pole until finally there are no more lines of latitude to travel, just a point (the North Pole).

The teaser is this. Say you're a mile from the North pole, and you look straight down a latitude line that is really close to the North Pole (I dunno, call it 89.999999 degrees N), will you be able to see the back of your own head on the horizon? Why or why not?
 
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Ulnarian said:
Say you're a mile from the North pole, and you look straight down a latitude line that is really close to the North Pole (I dunno, call it 89.999999 degrees N), will you be able to see the back of your own head on the horizon? Why or why not?

I do recall an article in Scientific American in the mid-90's maybe that was suggesting that there are such points in proximity to black holes. The light supposedly would bend around the black hole, effectively remaining in orbit. Of course, I think there's a lot of issues involved there, but it was an interesting idea nonetheless...

DaveE
 
Ulnarian said:
So I got to thinking about lines of latitude recently.

Since the Earth is a sphere, that means that, at the equator, a person would have to walk pretty far to go all the way around the Earth.

Now, as you head towards the North Pole, if you keep walking along the lines of latitude, you will find that your distance traveled to circumnavigate the Earth becomes shorter and shorter as you approach the pole until finally there are no more lines of latitude to travel, just a point (the North Pole).

The teaser is this. Say you're a mile from the North pole, and you look straight down a latitude line that is really close to the North Pole (I dunno, call it 89.999999 degrees N), will you be able to see the back of your own head on the horizon? Why or why not?
Obviously not. You line of sight does not curve with the circular line defining the latitude.

Can you ask a serious question?
 

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