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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Is light the fundamental building blocks for 3 dimensional visualisation?

What really makes a object 3 dimensional? I know that anything that has length, breadth, and depth can be considered a three dimensional object. But let's imagine that we lived in a world where the ...
6
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2answers
144 views

What causes the dimensions of a star increase when its hydrogen fuel is exhausted?

What causes the dimensions of a star increase when its hydrogen fuel is exhausted? For example, the Sun is expected to increase its radius 250 times. What causes this if its temperature is expected to ...
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45 views

Rosenberg-Coleman effect

I know only that it states some variations of the Sun's magnetic fields. What is the Rosenberg-Coleman effect specifically?
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0answers
43 views

What is the shape of the Sun's orbit around the Milky Way? [on hold]

Here is a question for you really bright folks. How does the motion of the sun along the midpoint of the plane of the galaxy look like? I suspect it to travel above and then below the plane but I ...
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1answer
53 views

The origin of the colour of the sun

I have learned so many concepts under astrophysics and unfortunately, I have muddled everything together... Let me try to illustrate my problem: When a star is in main sequence, it fuses hydrogen to ...
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1answer
45 views

How far in meters from the Sun's center is the Earth-Sun center of mass?

Like any set of massive objects separated by distance, the Earth and Sun have a center of mass. How far in meters from the Sun's center is the Earth-Sun center of mass? Just curious? Also what percent ...
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1answer
27 views

Duration of Satellite orbit in the shadow of the Earth

I want to determine how many minutes a satellite is in a circular orbit around the Earth at about $1000 km$ altitude. I assumed that the Sun-Earth vector lies exactly in the orbital plane of the ...
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1answer
272 views

Calculate the latitude / longitude coordinates of the location where the Sun is at the zenith

There are plenty of resources showing how to calculate zenith and azimuth of the Sun when the time and the location are given. However, I need to calculate the location where the sun is at the ...
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3answers
94 views

Would we be able to hear the sun if space were full of air? [duplicate]

I was wondering if the sun could be audible from earth in an air-filled space scenario. We can ignore all the other disastrous consequences! Thanks!
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1answer
55 views

Is sun revolving around certain mass in space with reference to some other galaxy?

Every planet and satellite revolves around their mother planet and about their own axis as we know. So they are compacted as a system. Then why not sun?
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2answers
59 views

Does a form of energy exists without any medium?

Sun contains fire,is it?Or some pure form of energy?If space has no air how can fire exist there,it may exist cause a burning piece of magnesium keep on burning in vaccum but,to start fire,oxygen is ...
2
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2answers
51 views

Sun: When its closest and when its farther away?

If the sun is closest to the North American Hemisphere in the winter than it is in the summer, why doesn't our faces and hands tan and/or blister quicker? Please provide two hyperlink sources with ...
3
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2answers
83 views

Does the Sun produce audible sound?

Theoretically if I were able to build some sort of device that let me sit 1 foot away from the surface of the Sun (or any star for that matter) without being vaporized, would a star produce any sort ...
3
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1answer
24 views

Sun energy production as a function of depth

I've heard a few times that the Sun's energy output per unit volume is less than that of a human, with the Sun's much higher power output being a result of its much greater size. In a blog post, ...
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3answers
132 views

Why is spectrum obtained by sunlight, said to be continuous?

My sir spoke about atomic spectra today. Sir said that, unlike the spectrum obtained by analyzing the sunlight, the spectra of atoms are not continuous. I got a doubt here, i,e even the sunlight ...
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5answers
2k views

Does the sun rotate?

As implied from the question, does the sun rotate? If so, do other stars not including the sun also rotate? Would there be any consequences if the sun and other stars didn't rotate? Me and my friends ...
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1answer
354 views

How fast is the Earth-Sun distance changing

This is inspired by Evidence that the Solar System is expanding like the Universe?, which referenced an article by G. A. Krasinsky and V. A. Brumberg, "Secular Increase of Astronomical Unit from ...
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2answers
191 views

Light formed by the sun?

This is an extract from the astrophysics chapter in my book: Hydrogen atoms fuse to form helium. At the same time, lots of of gamma photons and neutrinos are produced. The photons take thousands ...
11
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1answer
134 views

Why do some sunsets have a green flash?

Some sunsets exhibit a phenomenon called "green flash," where there is a quick flash of green light right as the sun is setting. I have seen this myself several times, and sort of understand it. I am ...
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3answers
177 views

What happens to the electron companions of cosmic ray protons?

If primary cosmic rays are made mostly of protons, where are the electrons lost, and does this mean that the Earth is positively charged? Does the sun eject protons and electrons in equal number?
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1answer
82 views

Why does the Sun turn red near sunset?

At daytime the Sun's light is yellowish if not near white. Why when the Sun starts to go down that it's light turn more red. I don't think the earth's rotation is so rapid to cause a red shift. Why ...
3
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2answers
81 views

Why aren't solar panels efficient?

Why can't solar panels produce 1 Kw per 1 square meter? This is the energy of the Sun's radiation per square meter on Earth but solar panels don't come close. Why can't we trap all that energy? ...
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3answers
4k views

How fast will the sun become a red giant?

I've read many accounts of our sun's distant fate, but what I've never heard is on what time scale these events occur. For instance, when the sun runs out of hydrogen, I presume it doesn't just WHAM! ...
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6answers
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Can the apparent equal size of sun and moon be explained or is this a coincidence?

Is there a possible explanation for the apparent equal size of sun and moon or is this a coincidence? (An explanation can involve something like tide-lock effects or the anthropic principle.)
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2answers
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What would happen to wet laundry in the vacuum of space?

Imagine for a second that I was in a college dorm room frustrated that all the dryers were broken or in use. I'm impatient and not a jerk so I don't wait or take out someone else's laundry, I shoot it ...
3
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1answer
42 views

Stellar Activity Cycle versus Metallicity

Our Sun exhibits sunspot max/mins on about a 11 year period. It's a G2 spectral class on the HR Diagram. We know that some stars exhibit "starspot" cycles of various intensities and periods. These ...
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1answer
104 views

Earth's Temperature [closed]

I have a question regarding earth's temperature... How come the average temperature in the middle east (Israel, Saudi Arabia, Sudan or lower) is always so much significantly higher than in Europe ...
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4answers
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Why is a new moon not the same as a solar eclipse?

Forgive the elementary nature of this question: Because a new moon occurs when the moon is positioned between the earth and sun, doesn't this also mean that somewhere on the Earth, a solar eclipse ...
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3answers
162 views

A question once confused Confucius

A well known story "Two Children arguing about the sun" (From Lie Zi, ca. 500BC): On the way traveling to the east, Confucius saw two children were arguing. One child thought that the sun is ...
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1answer
35 views

Question about the refraction of Fresnel lenses

If you line up the suns rays parallel to a Fresnel lens, the light is concentrated, and the focus directly underneath. However, what happens if the sun is off to the side, making the light hit at an ...
2
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1answer
111 views

Strömgren Sphere of Sun

I have a homework problem: The Sun emits $ \sim5 x 10^{23}$ photons per second with $hν > 13.6$ $eV$. If the density of hydrogen atoms in interplanetary space is $n =$ $109 m^{-3}$, what ...
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2answers
97 views

Is it possible to focus the sun in such way?

Imagine the sliding part of the mirror is controlled by computer and opens on intervals. Is it possible to increase the power of the beam by making it bounce between the mirrors thus going through ...
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3answers
376 views

What cosmic event would cause Sun rising from the west?

I'm wondering what kind of astronomical or geological events would cause the reversal of Earth's rotation. For instance, Is a meteorite passing very close to Earth able to reverse its rotation? Can ...
8
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1answer
118 views

The effect of dark lines in the Sun's spectrum on reflected paint/ color

Its well known that the Sun's spectrum is not continuous, and that there are dark bands within the suns spectrum. Is it possible to produce a color of paint that is bright in, say, indoor lighting and ...
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1answer
1k views

Application of diffraction problem!

Here is a problem that I am working on, which is the applying the concepts of diffraction to the setting of the sun: Air has a small, usually negligible index of refraction. It is 1.0002926. This ...
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3answers
168 views

Calculating the solar power hitting Earth

I'm trying to calculate the amount of power from the sun hitting the earth, but I am getting a number which is off by a factor of ~4. I calculate the "area" of the earth, as seen from the sun, and ...
3
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1answer
651 views

What size will the Sun become once it is a red giant?

How big will the Sun be once it becomes a red giant? How much of the solar system will it engulf?
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2answers
110 views

Gravitational Effect Versus the Speed of Light [duplicate]

If, for some reason, the sun were to suddenly disappear altogether, I would like to know the following: would we "feel" it first (i.e. being thrown into outer space due to no longer having anything ...
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3answers
4k views

How long until the sun cannot sustain human life on earth?

The sun will last, at its current brightness for 9 billion more years. How long until the sun gets burned down to the point where it cannot sustain life on Earth anymore? Updated: I am more concerned ...
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3answers
272 views

How can anything be hotter than the Sun?

I've heard that if a space shuttle enters the atmosphere from a bad angle its surface will become so hot that it will be hotter than the surface of the Sun. How can that be? It seems to an uneducated ...
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3answers
105 views

When was the earliest understanding that the stars were similar to the Sun?

When did astronomers realise that the stars were similar to the Sun? I'm not asking for when this was established, but when also the hypothesis was first proposed.
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2answers
340 views

Producing energy from magnetic flux loops

I've simplified this down by quite a lot but as far as I understand it, magnetic fields on the Sun's surface twist together and when it gets all a bit too much they release energy. My question is why ...
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1answer
90 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
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1answer
162 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 ...
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1answer
134 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 ...
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252 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 ...
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0answers
35 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?
3
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0answers
141 views

What is the Correlation Between Solar Wind Velocity/Density and Sunspot Count?

We have the Advanced Composition Exporer (ACE), which orbits in the L1 libration point as a source for solar wind velocity and density (particles/cm^3) data. Typically, at a velocity in the range of ...
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1answer
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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 ...