[Pinky]

So, the Sun moves farther away from us during the day.
https://wiki.tfes.org/The_Setting_of_the_Sun

From its point of view, we occupy a smaller and smaller fraction of its 4*pi spatial angle. This means, we get less and less of its photons.

However: The Sun at the same time stays at the same observed size due to glare. To us, the Sun keeps occupying the same angle and same area in the sky.
https://wiki.tfes.org/Magnification_of_the_Sun_at_Sunset

This means, that less and less photons are coming from an area in the sky that stays at the same size.

And this means, the Sun would have to get darker throughout the day. Not simply less daylight as the same amount of sunlight is stretched with 1/cos(alpha) over more and more terrestrial area. But a real decline of brightness of the Sun-disc itself.

And we do not observe such a change in brightness...

[Tom Bishop]

It does get darker. Look at the sun when it is directly overhead, and then look at the sun when it is near the horizon.

[Pinky]

It does get darker. Look at the sun when it is directly overhead, and then look at the sun when it is near the horizon.

Fairbanks, Alaska
Dec 16th, 2010


As you can see, as soon as it's above the horizon, the brightness in the inner part of the Sun-disc stays the same.

[AATW]

I’m not sure this is a great argument. You can look at the sun at sunset in a way you can’t safely when it’s overhead.

The constant size and angular velocity is a better argument. That is good evidence for a globe earth rotating - an alternative explanation would be the sun going over a flat earth but then the sun would go over and under the flat earth. Day would be day everywhere, night would be night everywhere. That is probably what the ancients believed, fairly reasonable without access to global transport links and communication. Now we know better of course.

[LoveScience]

It does get darker. Look at the sun when it is directly overhead, and then look at the sun when it is near the horizon.

Yes in RET the Earth is surrounded by a layer of air called the atmosphere. When the Sun (or Moon for that matter) is close to the horizon the amount of light absorbed by the atmosphere is much greater than it when the Sun is seen higher up in the sky. Hence the Sun looks less bright as it rises and sets.

How you explain it is anyones guess.

[BillO]

Another related question is, why does it not get smaller?

If it is only 3K miles away when it's overhead, it should be 1/10 the size when it's about to 'set' 30K miles away.

But that's not what we see, is it?

[LoveScience]

Not quite no... the Suns apparent angular diameter on the sky does vary very slightly through the year due to the elliptical shape of the Earths orbit.  At perihelion in December it is slightly larger than it is at aphelion in June. Common knowledge to the 'rest of us' of course but I'm sure the FE fraternity will have a different view.  Based on what though?

[BillO]

Not quite no... the Suns apparent angular diameter on the sky does vary very slightly through the year due to the elliptical shape of the Earths orbit.  At perihelion in December it is slightly larger than it is at aphelion in June.

Very true, but it's not quite the point I was trying to make.  I was looking on a more day length scale rather than an annual cycle.

Nonetheless, when this question (and others like it) gets asked there is either silence (If you ignore it, it might go away) or is faced with "Why do we need to explain things like this?", or some explanation that defies even the usual meaningless dribble set forth by various flat earthers as explanations for what is observable.  It depends on who you ask as there seems to be no consistency throughout the various FE 'groups' and certainly no explanations backed with any kind of scientific model.

[Spingo]

I think it all comes down to either what is actually there, or what you believe is there.

I’m sure the brightness of the sun fluctuates, but not so we would ever notice. Of course the brightness of the sun doesn’t change, that is a ridiculus concept. While the sun may be setting for me and light levels are dropping, it’s high in the sky andbecoming brighter for someone else.......at the same time!

It’s not the sun changing Tom, it’s us. If you can’t understand that pretty basic conceptthenthere is no hope!

Im in Scotland, it’s morning and it’s dark outside.....no Sun. if you asked someone living in Istanbul they would say the opposite as it’s late morning and sunny! For those in The USA, it’s the middle of the night and pitch black. In Peking it’s late afternoon and sunny! How is this happening Tom? One sun different light levels around the planet.

This deliberate twisting and misrepresentation of known facts is pointless. Rowbotham and his ideas are plain bonkers, particularly those relating to the sun, which we can all see. Of course it gets darker in the evening, but that’s nothing to do with any changes in light output from the sun!.....does Tom think it has a dimmer switch fitted?

Let’s not talk about changes in size,as that doesn’t happen either!

[LoveScience]

Very true, but it's not quite the point I was trying to make.  I was looking on a more day length scale rather than an annual cycle.

On a daily basis the Suns apparent diameter remains the same. Any apparent changes with altitude in the sky are purely atmospheric effects. People often say that the Sun or Moon look larger when they are low down but this is a combination of a very slight magnifying effect by the atmosphere and optical illusion. 

Whether you choose to believe that or not it is true.

[BillO]

On a daily basis the Suns apparent diameter remains the same. Any apparent changes with altitude in the sky are purely atmospheric effects. People often say that the Sun or Moon look larger when they are low down but this is a combination of a very slight magnifying effect by the atmosphere and optical illusion. 

Whether you choose to believe that or not it is true.

I'm not sure where you think I am arguing against you or whether I'm believing you or not.  I agreed with you.

[LoveScience]

BillO,   when I said

Whether you choose to believe that or not it is true

That was obviously aimed at those who make the ludicrous comments about the Sun being only 3K miles away or for that matter just 32 miles across. Such dimensions are only applicable when we are dealing with neutron stars. That I am pleased to say will never apply to the Sun!