150 votes
Accepted

What place on Earth is closest to the Sun?

This is an interesting question, but it lacks a key factor that is crucial to the answer: TIME. The point on Earth closest to the Sun varies through time, so the question can be asked about any ...
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29 votes

Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?

The clouds can be seen moving but of course it's subtle at first glance. Frame 16: Frame 20:
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27 votes
Accepted

Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?

They are moving, but not fast enough to notice at the distance shown. From the NASA page: These images were taken between 3:50 p.m. and 8:45 p.m. EDT on July 16, showing the moon moving over the ...
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  • 11.1k
21 votes

What is this Sun and moon photographic anomaly?

The apparent anomaly, known as the Lunar Terminator or Moon Tilt Illusion, is indeed a matter of perspective. A brief explanation can be found here: http://chrisjones.id.au/MoonIllusion/ The essence: ...
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  • 211
11 votes

Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?

The image is real, and the clouds are moving, they just move slow, as clouds do. The unnatural appearance arise because they are taken by DSCOVR at an extraordinarily large distance, from a place ...
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11 votes
Accepted

Why high tides occur simultaneously on opposite sides of the Earth?

First of all, tides are not as simple as the "two-bulge" simplification. In reality, the diagram shown is misleading. The two bulges appear assuming an ocean of constant depth covers the ...
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  • 14.7k
10 votes

Does general relativity influence climate (vs Newtonian mechanics)

In short: No. Unless multi-million timescales are considered. The reason we keep teaching Newtonian mechanics, is because it is a VERY accurate approximation of a more general theory (general ...
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10 votes

What is the distance between the tropics?

Let's start by the quick rule of thumb, I'll follow the way I do it mentally as I think the mnemonics I use could help you too. First, the tropics are at 23.5° of latitude. And remembering that the ...
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10 votes

What place on Earth is closest to the Sun?

It is impossible to know. Solar flares can have more than 500,000 kilometers. So if we consider them part of the sun, the moment when the earth is closer to the sun can be very different from ...
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  • 109
8 votes
Accepted

What is the distance between the tropics?

Both the tropics of Capricorn and Cancer are 23.43692 degrees from the equator. So the angular distance between the two is 46.8738 degrees (2 x 23.437) of latitude. One nautical mile is defined as ...
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  • 20.3k
8 votes
Accepted

Why does more sunlight hits the equator than the ecliptic path?

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 ...
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8 votes

Why high tides occur simultaneously on opposite sides of the Earth?

Tides arise from the differences in gravitational pull across an object. That's why their strength falls as $r^3$ instead of $r^2$ (where $r$ is the distance between the two objects). Visually it can ...
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7 votes

What is this Sun and moon photographic anomaly?

Here my wife holds a globe with the moon in view. I carefully processed in a bit-mode to find the curve of light on the globe and drew perpendicular lines. Plainly we can see that the moon-lite side ...
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6 votes
Accepted

Where is the Arctic Circle for civil and astronomical twilight?

As mentioned by Barry in the comments, you just have to substract 6 degrees of latitude to get the ring around areas were it never gets DARKER than civil twilight or darker for 24 or more hours (or 12°...
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6 votes
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Why does the earth rotate in correlation with it's rotation around the sun to such precision?

I find it bizarre that the earth rotates at nearly exactly 365 1/4 times per year, requiring an extra day every 4 years. The Earth does not rotate nearly exactly 365 1/4 times per year. That's the ...
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4 votes

What place on Earth is closest to the Sun?

The point on the surface of the Earth where the Sun is currently immediately overhead is called the Zenith Point. Its Latitude and Longitude correspond to the Declination and Greenwich Hour Angle of ...
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4 votes

What is this Sun and moon photographic anomaly?

You can see this effect on the powerline above the railroad tracks in the picture you posted too, it doesn't look straight, even though it likely was in reality! The straight line between the sun and ...
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  • 1,959
4 votes
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Calculate the maximum power angle of a solar panel (photovoltaics)

This question can be answered in many different ways that take into account, or ignore, the many factors that affect the total output of a fix solar panel over a year. In general, all answers will ...
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4 votes

What will be the temperature on Earth when Sun finishes its main sequence?

Answers will be different because they must be tied to a model of solar evolution, and all models are a bit different. So to answer your question we have to select a model. A pretty standard and ...
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4 votes

Equations for Milankovitch Factors?

There are many models that estimate orbital parameters at long timescales. All of them rely in rather complicated formulas that account for the perturbations generated by other planets, the Moon, and ...
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4 votes
Accepted

What causes this arc in the night sky where the background is brighter on one side than the other?

What is happening here? Photoshop! The number of visible satellites plummets towards the middle of the night when more satellites fall into the shadow of the Earth, represented by the dark area on ...
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  • 196
3 votes

Does general relativity influence climate (vs Newtonian mechanics)

I don't see this point made, so I'll just add it. In very high gravitation situations orbital energy can be lost to "relativity" or more specifically, gravity waves. The primary relativistic effect ...
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  • 5,677
3 votes

Does general relativity influence climate (vs Newtonian mechanics)

The latest positions that I am aware of say yes, but not in any useful way. From what I have read, the current prevailing opinion is that the weather of Earth is a chaotic system. Chaotic systems ...
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3 votes

Why do meteorological seasons start earlier than astronomical seasons?

As JeopardyTempest commented: Actually, the astronomical seasons are defined in such a way that you should expect them to be a full 1 ½ months behind, not just 21 days! Namely, astronomical winter ...
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2 votes

Latitude and Daylight Hours

This tool lets you determine daylight hours from latitude for any day of the year. I feel like this answer should be longer, but there is not much more to say.
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  • 3,294
2 votes

Could evidence of a signal from an exocivilization be found in the geologic record?

You can just think of this in terms of energy. To leave a mark in the geologic record, you have to use something that is at least as strong as the forces that are shaping the world around you: erosion,...
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2 votes

Could evidence of a signal from an exocivilization be found in the geologic record?

No, it is not possible. The only thing I could think about is re/de/magnetisation of magnetic minerals. Even then I'm not sure it's feasible, because you to form a magnetic field you need an electric ...
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