Re: [Phys-L] Earths tilt

[John Denker <jsd@av8n.com>]

On 10/28/21 9:04 AM, jim cibulka via Phys-l wrote:

> If the earth wasn’t tilted, would the sun rise due east everywhere or
> would it change due to latitude?

The same, for all practical purposes.

  There are slight corrections due to the trigonometry of
  the situation, but they are negligible for all practical
  purposes, since the tilt is unlikely to be exactly zero,
  and the triangle involved is very skinny. Treating "the
  sun" as a pointlike object is a vastly worse approximation.
  One thing is for sure, the east/west line would be *well*
  within the sun's disk at sunrise/sunset.

> Wish I could change this on stellarium!

You can.
Just dial up the date of the equinox.
That makes the tilt irrelevant.

Furthermore, you don't need a simulation. The experiment has
already been done, and you can replicate it if you want.

On many occasions I have driven to/from work along an east/west
road. When the date is near the equinox, the rising or setting
sun shines directly in my eyes, which is super annoying. On other
dates, the sunrise/sunset is north or south of the east/west line.

If that's true at my latitude, it's a safe bet it's true at all
other latitudes.

One evening in late March I was walking alongside a big-shot
physics professor. We were both using our hands to keep the 
setting sun out of our eyes. She was complaining how easy it
was to get lost. (This was back in the days before everybody
had GPS built into their phones.) I asked her which way was
west. She had no idea.