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

learn more… | top users | synonyms

0
votes
1answer
108 views

How faster is the effect of force exerted by gravity? [duplicate]

We all know that Earth revolves around the Sun due to Gravitational force of the Sun. Also we know that it takes just over 8 minutes for the Sun's light to reach Earth. Now let us say, hypothetically ...
5
votes
1answer
189 views

Calculate sunrise, where does the magic numbers come from?

In this question about how to calculate sunrise, there is a link to a page that describes a algorithm to calculate sunrise sunset. But when I start to follow the instructions I find that there is a ...
1
vote
1answer
236 views

calculating the solar declination

I was looking at this page http://www.illustratingshadows.com/www-formulae-collection.pdf and found the equation used for estimating the solar declination (sun declination). One problem, though, I ...
8
votes
2answers
457 views

Entropy of the Sun

Is it possible to measure or calculate the total entropy of the Sun? Assuming it changes over time, what are its current first and second derivatives w.r.t. time? What is our prediction on its ...
1
vote
0answers
43 views

When sun is exactly overhead in my place in the tropics [closed]

What formula to use to find dates and times when the sun is exactly overhead in my place in the tropics?
2
votes
1answer
119 views
3
votes
1answer
127 views

Can the Solar System be assumed a single body concentrated in the Sun?

This question springs from a comment against my question posted on the Space SE My questions may seem inane, or obvious to most of you real physics people too ... Any number of sources put the peg ...
4
votes
2answers
168 views

How to measure declination of sun and moon?

I came by some graphs showing the declination for sun and moon (between angles of -30° and +30°). The graphs look very much like sine waves. I googled a bit and read about what the declination is, ...
11
votes
2answers
196 views

Could a mirror array used for thermal solar power plant double as a telescope at night?

I was looking at the Ivanpah Solar facility and it occurred to me that the large array of mirrors could double as some sort of telescope array at night. The climate in the desert would be ideal for ...
5
votes
4answers
694 views

The Sun as a gravitational lens

Since the Sun is a gravitational lens with as focal length of 550 AU for visible light, with an immense amplification factor, shouldn't it light up objects hanging out there? We should get solar ...
2
votes
1answer
78 views

Does the sun's bearing at a given time vary, and if so, how?

More an astronomy question, but Physics is the closest stack exchange category I could find and Google doesn't have the answer. Granted, the sun's elevation changes for a given time of day throughout ...
32
votes
3answers
6k views

Why is the sky not purple?

I realise the question of why this sky is blue is considered reasonably often here, one way or another. You can take that knowledge as given. What I'm wondering is, given that the spectrum of ...
2
votes
3answers
266 views

How can sunlight be white , but pictures of the sun be orange?

I was thinking about elementary physics today and realised: We learned and proved that sunlight is white. But i don't understand why when you look at a picture of a satellite orbiting the sun , it(the ...
18
votes
2answers
2k views

How long until we fall into the Sun?

As a planet moves through the solar system, a bow shock is formed as the solar wind is decelerated by the magnetic field of the planet. Presumably the creation of this shock wave would cause drag on ...
0
votes
1answer
107 views

Why was Galilei “right”? [duplicate]

Considering that all frames are equivalent, isn't it up to the observer to say "The earth turns around the sun" or "The sun turns around the earth"? Isn't this more or less like arguing about which ...
1
vote
1answer
437 views

What is the electric charge has the sun and the corona of the sun?

What is the net electric charge (in magnitude and sign) of the sun and its corona?
2
votes
3answers
2k views

Why is the colour of sunlight yellow?

I was going through the preliminary papers of other schools and found a question that I did not know. It was "Why sunlight appears yellow?". Can anyone answer it?
3
votes
1answer
222 views

What is the sun's spectral series?

My physics book says that six colors can be distinctly seen in white light: red, orange, yellow, green, blue, and violet. Does solar light only use these six wavelengths and mix them additively, or ...
2
votes
2answers
412 views

How to calculate the amount of night time during a flight?

I have been asked to find a way to calculate the amount of time that a flight takes during night time. So far, I have the departure latitude and longitude and the time of takeoff, the arrival ...
7
votes
1answer
350 views

Has Voyager 1 entered a solar radiation belt?

The Voyager 1 probe was sent out in 1977 to go where no man made object has gone before, after more than 35 years it’s still going strong. It’s now 124 AU away from Earth and many are wondering when ...
0
votes
4answers
118 views

Revolution of Earth [duplicate]

If all motion is relative, how do we know that the Earth revolves around the sun? Or we are just making the above statement from the frame of reference in which Sun is at the origin?
6
votes
1answer
207 views

Can solar furnace achieve higher temperature than sun surface? [duplicate]

Can solar furnace achieve higher temperature than sun surface? I guess not, but I'm not sure about that. Can you check my reasoning: -------- My reasoning ----------- Consider Sun as a black body ...
8
votes
1answer
279 views

How can one get the eccentricity of the orbit of the Sun around center of the Milky Way?

How can one get the eccentricity of the orbit of the Sun around center of the Milky Way? Can it be measured?
8
votes
5answers
457 views

sun-moon-earth anomaly

When one looks at the sun and the moon in the sky together, why is it that the illuminated crescent of the moon does NOT "point" at the sun? (More correctly the perpendicular bisector of the straight ...
6
votes
3answers
718 views

Why does the light side of the moon appear not to line up correctly with the evening sun?

I live at roughly 52.4,-2.1. On a sunny evenings I've often looked at the moon and the sun and noticed that the light part of the moon does not appear to line up with the sun. For example, at about ...
2
votes
1answer
376 views

How much does sunlight affect inside temperature?

Suppose we have a $3\cdot 3\cdot 3\,m^3$ room of which one side is glass. And suppose that the other 5 sides have no effect on temperature (super isolation). We know from physics how to calculate ...
2
votes
2answers
233 views

How is the sun's equatorial circumference measured?

How is the sun's equatorial circumference measured by scientists?
3
votes
1answer
87 views

How does irradiance behave over time?

I am trying to clarify data on weather from the Royal Netherlands Meteorological Institute (KNMI); I have incorporated the Solar Position Algorithm (SPA), such that I can calculate sunset and sunrise ...
3
votes
1answer
224 views

Calculating the length of day at any time of the year? [duplicate]

Is it possible to calculate the length of the day at various location (distances) from the sun? I hear agricultural scientists are able to do that. To make calculations easier assume there is no axis ...
6
votes
1answer
672 views

Is there a simple yet accurate formula for where on Earth the Sun and Moon are directly overhead?

I'm trying to improve a site that shows the region of the Earth currently under daylight, and I need a formula that, given the current time, tells where (latitude/longitude) the sun and moon are ...
0
votes
1answer
211 views

Does brown but transparent swimming pool water heat significantly faster than western style highly chlorinated pools?

Eastern European swimming pools are often brown tinted water. i was told it was the color of the chemical to keep the pools clean, but who knows. These pools did not smell unsanitary and may have even ...
1
vote
1answer
931 views

When should angles be expressed in degrees vs. radians?

I am trying to calculate the albedo of a given latitude by following the methods of Brutsaert (1982), I have copied the formula below: 3.6 Shortwave and long-wave radiative fluxes Albedo ...
7
votes
2answers
189 views

Must a vertical sundial face exactly South?

I am a sundial. I'm prepared to bet Your watch can't tell when the sun will set I once heard Frank King talk about sundials in particular this very cool one, which measures Babylonian hours ...
5
votes
2answers
294 views

Attenuation mass-thickness for sunset light

We are able to look directly at the sun near sunset and sunrise, which clearly demonstrates the fact that our atmosphere attenuates visible light. Let's imagine it follows the typical attenuation ...
7
votes
3answers
908 views

How many percent of the visible light reaching the Earth are from other stars than the Sun?

How many percent of the whole visible light reaching the Earth are from other stars than the Sun? Is it maybe 0,5 - 1% or is my guess already too much? I am interested mainly in visible light, but ...
0
votes
1answer
75 views

Do particles in the solar core travel at the same speed as they would in vacuum?

I just read the Wikipedia article on the Sun. The section on Solar Core states It has a density of up to 150 g/cm3[47][48] (about 150 times the density of water) Do the particles (atomic, and ...
3
votes
4answers
2k views

Modeling incoming solar radiation

I want to write a model for estimating incoming solar radiation for a specific latitude on earth but I am struggling to find an appropriate source which shows the required equations for doing so. ...
2
votes
3answers
194 views

How old is SUN ☉?

How do we know/calculate the exact age of sun ☉ ? ie. 4.57 billion years. What is the way to calculate it?
10
votes
1answer
159 views

Have general relativistic effects of the sun's rotation been measured?

I was wondering if general relativistic effects of the sun's rotation have also been measured, like gravity probes A and B measured GR effects from the earth.
6
votes
2answers
395 views
5
votes
3answers
502 views

Why planets are rotating only in one plane? [duplicate]

Since gravity is three dimensional why planets are rotating only in one plane around sun.
0
votes
1answer
43 views

Produciton of EM waves with differing wavelengths

Sun is the major source of electromagnetic radiation. Then if the source is the same, how are different EM waves with differing wavelengths produced?
0
votes
0answers
34 views

What is the formula for calculating the length of any given day (sunrise to sunset)? [duplicate]

In a specific date what law gives us perfect measurements and how will we measure if latitude is given?
-1
votes
1answer
94 views

How much energy is needed to curve the space so the Sun will come 1 meter closer to our planet? [closed]

How much energy/work will it take if our planet is: 5.9736×1024 kg or 3.0×10−6 Suns to move Sun and Earth 1 meter closer ...
10
votes
1answer
12k views

Why can there be fire in space while there is no oxygen?

The sun is made of fire but fire needs oxygen right? So.. Why can there be flames in space, while there's no oxygen? Same idea as with the rocket engines of the spaceship, which also produce fire ...
3
votes
6answers
2k views

The Sun Can Make Stuff Hotter Than Itself

We intuitively understand the direction that energy travels -- from the thing with energy to the thing with less energy. That's why the second law of thermodynamics is among the first things you learn ...
3
votes
3answers
82 views

Distribution of each element and molecule as a function of distance from the Sun and as a function of time

Are there any graphs that show the distribution of each element and molecule as a function of distance from the Sun? And maybe even the time-evolution of each distribution over the solar system's ...
4
votes
2answers
217 views

What is the mass distribution within the sun?

Jupiter is roughly 1/1000 the total mass of the sun. To get some idea of what effect Jupiter's gravity may have on the sun I'd like to know the approximate mass distribution of the sun. (i.e) the ...
3
votes
2answers
233 views

Was Sun a part of a binary system?

I've read that many stars and other celestial bodies are found to constitute binary systems where the two bodies spin around each other. But our Sun is one of the exceptions. Could it be possible that ...
4
votes
1answer
2k views

Force on Earth due to Sun's radiation pressure

I have been asked by my Classical Electrodynamics professor to calculate the force that the Sun exerts in the Earth's surface due to its radiation pressure supposing that all radiation is absorbed and ...