“I disagree with Legrande’s religion, but what is wrong with the simple concept that when you look at the sun it is not, at that time, where it appears to be? It takes 8.5 minutes for the light to get here, by the time it gets here, it has moved a little.” [excerpt]
Exactly
how far does the
Sun move in 8.3 minutes?
You are correct that it is not
exactly where it appears to be.
This is caused by
Aberration of Light.
From the above link:
- Annual aberration is due to the revolution of the Earth around the Sun.
- Planetary aberration is the combination of aberration and light-time correction.
- Diurnal aberration is due to the rotation of the Earth about its own axis.
- Secular aberration is due to the motion of the Sun and solar system relative to other stars in the galaxy.
The displacement of the apparent position due to
Annual aberration is calculated as follows:
atan(30 000 / 299 792 485) * (180 / pi) * degrees = 20.6407581 arcseconds [
Calculate]
Where 30,000 is the speed in Meters per second that the Earth is traveling around the Sun, and 299,792,485 is the speed of light.
The displacement of the apparent position due to
Diurnal aberration is calculated as follows:
atan(463.8 / 299 792 485) * (180 / pi) * degrees = 0.319106121 arcseconds [
Calculate]
Where 463.8 is the surface speed of the Earth at the equator in meters per second. (changes with the latitude of the observer)
The
(180 / pi) just converts radians into degrees.
When you add the two together, you get a maximum displacement of around 20.9598642 arc seconds or 0.00582218451°. (depending on latitude, etc)
LeGrande has asserted that there is 2.1° degrees of displacement all due entirely to the rotation of the earth.
However, the displacement of apparent position due to the rotation of th earth (Diurnal aberration) is a maximum of around 0.319106121 arc seconds, or 8.86405892 × 10
-5 degrees.
“What is wrong about that?” [excerpt]
Its not that 2.1° of displacement due to the rotation of the earth is
wrong, its just that its not right, and is certainly not supported by science.
OK, you were debating the size of the displacement, not the concept. I understand, and am with you. thanks.