The Sun is an almost perfectly symmetric yellow dwarf star [spectral class G2V] which is at the center of our Solar System.

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Static model of the Earth motion

Believe it or not, an old man I know in 2015 still negates the Earth orbital motion around the Sun. He believes the earth is rotating on itself and acknowledges this gives day and night on every ...
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1answer
88 views

Would a giant satellite laser work as a weapon?

If someone built a satellite to float about in space, which used mirrors to focus and magnify energy from the sun directly into one direct spot (like in the James Bond film Die Another Day) would it ...
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1answer
59 views

Effect of radiation pressure on Earths orbit in large timescales

I have seen some posts concerning the radiation pressure exerted by the Sun on Earths surface (Force on Earth due to Sun's radiation pressure). Though it is fairly small may it have a considerable ...
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1answer
50 views

How close to the surface of the Sun would one have to be to determine an 'upright' position relative to it's surface?

As we stand upon the surface of the earth we're able to establish a relative 'up' and 'down' direction due to gravitational forces. As we leave the confines of the earths gravitational attraction ...
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1answer
68 views

What unusual effects will we observe on the non-rotating Dyson sphere with earth gravity around the Sun?

First let's place our sphere Let's assume there is a two-layer non-rotating Dyson sphere around the Sun (ignore the scale): Green is empty air. How far should the inner border of this sphere be ...
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1answer
81 views

In what ways does the sun output energy?

I'm curious about the energy output of the sun, and how it breaks down. What fraction is from EM radiation, solar wind, neutrinos, et cetera? How does energy output vary over the EM spectrum? I was ...
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30 views

Inclination of planets

What is the inclination of each planet with the equator of the Sun? Doesn't this have a relationship with the eccentricity of the planet's orbit?
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1answer
469 views

If the sun stopped burning, would we ever know it?

I read somewhere that since gravity moves at the speed of light, if the sun were to leave its position we would "know" about it through the absence of light and its gravitational effects on our planet ...
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1k views

How do you estimate colour temperature based on the position of the sun in the sky?

I'd like to estimate the colour-temperature of sunlight (as applied in photography) based on the position of the sun in the sky for a mobile phone app I'm working on (app link from a more appropriate ...
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0answers
52 views

How to correctly calculate the colour of the sky?

It is well-known that the sky is blue due to Rayleigh-scattering. What bothers me though is the question how to actually calculate the spectrum of the scattered sunlight. Yes, use one of the ...
3
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0answers
36 views

Surface UV exposure with cooler star

If the sun's surface was ~ 4000K (and earth closer to compensate), the UV component of the radiation would be less. However, UV makes ozone via photolysis of oxygen. Also, the stratosphere would ...
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116 views

Was Aristarchos' method to compute Earth-Sun distance ever rediscovered in medieval or modern times?

Ancient Greek astronomer Aristarchos who lived around 300 BC found a method to compute the Eart-Sun distance by applying geometry. In this video about the cosmic distance ladder, at 26:30, Terence ...
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Generic Rayleigh effect experiment - nothing happens for water

On youtube, a bunch of Rayleigh scattering experiments (e.g this one are set up with some compound being added to water in order to invoke the effect. Why is there no Rayleigh effect for "pure" water?...
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96 views

How to derive equation for time it takes photons to diffuse through the Sun

I am wanting to use the Rosseland radiative heat flux equation to find the time it takes for photons to diffuse through the sun. The answer I am wanting to derive is: $$\tau_D~\frac{\rho \bar C_p R^...
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0answers
23 views

Color Temperature Variation of Sunlight

I want to know what is the Variation of the color temperature in Kelvin of Sunlight as viewed from the earth from Sunrise to Brightday to Noon to Sunset. Will there be any change in the color ...
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0answers
18 views

Experiments on the melting of snow?

When snow melts there are three main variables: the temperature of the air, the altitude of the sun, and the distance of the sun from the earth (which changes because the earth moves in an ellipse ...
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0answers
26 views

Energy potential of a cold sink inside the sun

An answer in this question discusses using a fusion engine in a theoretical spaceship within a star. http://worldbuilding.stackexchange.com/questions/37589/what-are-the-consequences-of-literal-...
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0answers
30 views

How to calculate apex angle of sun shining on the Earth

I'm trying to compare the brightness of various LEDs to the average brightness of natural daylight. LEDs are rated in terms of candelas whereas the Sun is measured in terms of lumens, so I need to ...
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0answers
26 views

Does sun's geographical(not magnetic) polarity changes?

What i am asking is, do sun's north pole & south pole reverses, resulting rotation change?
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0answers
295 views

What is a magnetic flux rope and how does it differ from magnetic flux tubes?

I am currently taking a course on solar physics and it appears the terminology in solar physics is either needlessly verbose or I am just missing something. What is a flux rope and what is a flux ...
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0answers
64 views

Explanation for strange atmospheric phenomenon

OK, I've seen this strange thing in the sky sometimes. Not all that often, but sometimes. It actually happened tonight. On most nights, at say 9 P.M. it is dark. There might be stars, moon, etc.,...
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38 views

Different ways of converting solar energy to other forms of energy

Okay so after receiving our Physics papers today I decided to tell the teacher why I lost marks on the last question: "Mention the energy conversions undergone here Sun --> Coal-fired boiler --> ...
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0answers
120 views

Determining rotational period of sun using sunspots

I know that at the equator at 0 degrees latitude , you could track a sunspot and then use T=2pi/w and w=∆theta/∆t to work out the period the equator rotates, but how would you do it for, say, sunspots/...
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0answers
36 views

Variance of daylight over short periods of time?

I've searched various publication archives but I'm a signal processing engineer and not an applied physicist, so I might not be using the right terms. While I can find various average values for the ...
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0answers
59 views

How do you calculate the heat build-up inside a building or container as a result of the sun?

I need to calculate how much heat builds up in a closed environment eg a building or a Chromadek container. One of the factors I need to take into account is the sun. I know there are various ...