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The main proxy that we have of past solar intensity comes from its proven correlation to the number of sunspots, which have been recorded since the invention of the telescope in the early 1600's. And the plot looks like this: We have no evidence of any significant correlation between the solar cycle and earthquakes or volcanic activity. You won't find ...

13

As noted in the comments, this answer applies to things like sun-bathing and solar panels, but it does not apply so much to a specific point-receptor like an eyeball. If all objects in question are pointing directly at the sun, then the angle of incidence is equal for all of them and this answer does not apply. For an optic facing its target, the amount of ...

8

Why does climate science divide total insolation by 4? For two reasons, each of which halves the effects of insolation: At any point in time, only half of the Earth is illuminated by the Sun. Another name for this factor is "daytime" versus "nighttime". At any point in time, the surface area of the Earth's hemisphere that is illuminated ...

7

On an average those would be the poles. As you correctly pointed out, due to the tilt of the Earth's axis, there are large areas that receive very little and sometimes no sunlight at all and those change throughout the year. But on an average, poles are the ones that get the least amount of solar radiation. For example, see this paper and in particular have ...

6

The ecliptic path, is a well defined trajectory when displayed on the background of the fix stars like in the following figure (taken from physics.csbsju.edu) However, there is not such thing as an ecliptic path on the surface of the Earth. If you thought of it as the "Ground track" of a satellite but applied for the Sun, you have to consider that the ...

5

I think you’re not far off with your understanding, but maybe I can put in a few comments to make things clearer. I often get confused because most diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place… As you can see, ...

3

My answer is mainly here to give some quantitative reasoning, but for the sake of completeness I'll also answer what my predecessors already answered. Why do we divide by 4? Imagine you see earth from the perspective of the sun. What you see is a disc. The area of this disc is $\pi r^2$ and therefore the total energy earth received from the sun is \$S_0 \pi r^...

3

As was pointed out in the question comments, there is no way to know what Earth's average temperature would do without water vapor in the atmosphere. However, we can estimate the effects of the water, and remove them. What follows is a rough approximation. If there were no greenhouse effect, the average temperature of Earth would be about 0F (-18C) ...

2

Any area south of the northern polar circle will have one peak per day,and the same goes for the southern polar circle any area north of this will have one peak per day,the polar circles is at 66,33 north/south. The areas whitin the polar circles will have only one peak per year but it will last for half a year. A solar panel will only produce significant ...

1

Climate science studies the processes on the Earth over the course of many centuries. The rotation of the Earth is so small compared to many centuries. Imagine that we roast the chicken. We can approximate the chicken as a sphere. The sphere (or chicken) is continuously revolving, thus the source of heat is changing the hemisphere that is being roasted. At ...

1

diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place. Is this because they count percentages or units of radiation twice? because some is re-emitted back? Consider the simpler case of a blackbody. The incoming radiation ...

1

The 5 factors you mention are not nearly as important to the effect you're asking about as another, more fundamental factor: time. If you've read my answer to this other question, you should understand that all of the factors you mention would create temperature differences at different latitudes whether the Earth is tilted on its axis or not. But because ...

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