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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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1answer
21 views

Some Rayleigh Scattering questions

Last week I've heard about Rayleigh scattering for the first time, when the classic 'why is the sky blue?' question has crossed my mind and I must admit that it is fascinating! However, I do have a ...
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2answers
49 views

What if the luminosity of Sunlight increased by 10% [closed]

If the luminosity of sunlight increased by 10%, would people be able to survive outside? Would such brightness of light be very harmful to them, for exemple as much as the Mercury Vapour Lamp without ...
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0answers
19 views

Radiative Forcing

In a first approximation the radiative forcing $RF$ is related to the temperature change by the linear relation $$ \Delta T = \lambda \, RF $$ where $$ \lambda\approx 0.8 \, \frac{{\rm K}}{{\rm W}/{\...
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1answer
29 views

What is the difference between granulation and supergranulation in the Sun's photosphere?

Granulation and super granulation seem to be some sort confused topics as they are due to the heated particles coming out of the surface. What is the difference between the two?
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1answer
92 views

Speed of sound at the Sun surface [closed]

The gas velocity at the Sun's surface is subsonic and At 1 AU from the sun, the solar wind is supersonic. Like Parker wind solution. Why the velocity at the Sun's surface is subsonic? (In the ...
2
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1answer
30 views

What is an active region in sun's photosphere? Why sometimes there is an active region but no sunspots?

What is the theory behind an active region? If we check data in solar monitors, there are some cases where there is no sunspot but there is still an active region. Why is that the case?
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1answer
93 views

How loud is the sun? [duplicate]

The sun is a continuous explosion. The reason we cannot hear the sun is because of the vacuum separating us. If that space was to be filled with air, would the sun be audible?
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0answers
40 views

Can you destroy the Sun if you throw enough iron into it? [duplicate]

i have a vague understanding of how the inside of the sun works, but i remember from class that when the sun started "making" iron on it's core, it cannot go further; can't make a heavier element. ...
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2answers
93 views

What determines the surface temperature of the sun?

The core temperature of the sun is on the order of 15 million degrees kelvin while its surface temperature is around 6000k. What are the main factors which determine the surface temperature of the ...
-2
votes
2answers
128 views

Does the Sun revolve around the supermassive black hole at the center of the Milky Way? [duplicate]

I'm curious to know, does the sun really revolve around the black hole at the center of the galaxy?
3
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1answer
52 views

Why acoustic glitches in stars translate into extra oscillatory components in the normal frequencies?

Acoustic glitches are locations inside the star where the sound speed changes abruptly compared to the wavelength of the acoustic waves that propagate through. Examples are the ionization zones and ...
1
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0answers
36 views

What are the average wavelengths and brightnesses of sunlight across the stages of twilight?

I understand that before sunrise, twilight shows several colors, so I'm looking for the average color (wavelength) and brightness (lux) of light that is being projected from the sky before the sun ...
6
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2answers
106 views

What would the sky look like if the Sun was a black hole?

As a complement of this Phys.SE question. What kind of lensing and diffractions effects from space would be perceived on earth?
2
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0answers
39 views

What portion of the total power emitted by the Sun comes from photons?

We usually talk about luminosity, which is the total power from emitted photons. The other sources are neutrinos and the solar wind (which includes protons and other particles). I assume that most ...
0
votes
2answers
95 views

Solar Neutrino Problem [closed]

I am not sure if this has been asked recently, but has there been any headway into solving the solar neutrino problem? I recently completed the Particle Physics for non-Physicists by Professor ...
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votes
1answer
38 views

how to get high humidity and low temperature in room [closed]

I want to start mushroom farm for that I have to maintain high humidity and low temperature for that ,So i finding solution for how to get high humidity and low temperature at low cost.
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5answers
171 views

Nuclear Fusion requirements?

So I kept searching for answers or reasons as to why the sun can generate nuclear fusion at 15 million degrees C when I research that nuclear fusion is achieved at 100 million degrees. Is it because ...
2
votes
3answers
76 views

How to calculate the Sun’s energy output? [closed]

What formula can be used to find the total energy being produced from the Sun in Joules per second? If I recall correctly, the energy is around $2.3012 {\cdot} {10}^{27}\,\frac{\mathrm{J}}{\mathrm{s}}...
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2answers
71 views

Proof against Tychonian model by view from Space

No earth-based observation of the planets can disprove the Tychonian model (planets orbit sun, which orbits the earth). It takes very fine stellar observations, which couldn't be done in the 17th ...
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0answers
33 views

What's the maximum temperature of a sealed air cavity within a blackbody?

I found this post on how to calculate the maximum temperature a black body could get in direct sun on planet earth: How hot can metal get in sunlight?. But, what I want to know is... If you made that ...
5
votes
2answers
664 views

What if we throw many buckets of water into the Sun?

What will happen if we throw many buckets of water into the sun and keep repeating the process? Will it get cooler or hotter?
39
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4answers
7k views

What would happen if Jupiter collided with the Sun?

This question is inspired by a similar one asked on Quora. Let's say a wizard magicked Jupiter into the Sun, with or without high velocity. What happens? The Quora question has two completely opposed ...
3
votes
4answers
67 views

Does the photons of light have an effect the movement of solar planets

In space, solar sails are used in order to move some space exploration crafts. Since in space there is vacuum the slightest force could be enough to propel and move the craft. Although the earth is ...
0
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0answers
37 views

Electron density in the sun

I'm currently working on solar neutrino and in order to make a numerical simulation, I need the potential felt by electron-neutrino : \begin{equation} V_e(r) = \sqrt{2} G_F N_e(r) \end{equation} where ...
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0answers
67 views

How much of Sun's mass is “regular” matter? How precisely do we know Sun's composition?

This is a question which spun of this Can the Sun / Earth have a dark matter core? I have argued that it is possible to pretty accurately estimate how much mass of Sun is in the regular matter, so ...
2
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1answer
47 views

Describing the Sun's interior

Can the interior of the Sun be described as an ideal gas? From my knowledge, to describe a body of gas as an ideal gas, the separation between the particles must be much greater than the size of the ...
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1answer
42 views

What causes the perceived intensity of the sun to change on a short timescale?

I was inspired by this question to ask, what causes the "beating down" feeling of the sun to vary day to day? While the linked post explains why the sun feels hotter in the summer than in the winter, ...
19
votes
1answer
3k views

Why does the sun “beat down” harder in the summer - or does it?

I know that seasons are caused by the Earth's axial tilt - in summer, latitudes away from the equator receive more surface irradiance (power per unit area), and vice versa in the winter, because of ...
50
votes
4answers
7k views

The Sun is giving us a low entropy, not energy

While I was watching a popular science lecture on YouTube, I came across this sentence "Sun is giving us a low entropy, not energy" which was said by Prof. Krzysztof Meissner. I am not a ...
1
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1answer
57 views

Would I see a mushroom cloud if I nuke the sun corona?

The sun corona can reach an extremely high temperature at least a few million degree, say if the temperature of the explosion of a nuclear bomb is roughly equal to the temperature of the corona then ...
0
votes
1answer
38 views

Why the color of Sun is yellow, red or orange? [duplicate]

Theoretically the maximum wavelength of sun radiation is approximately 500 nm. Then we should see the sun as green. But why do we see sun as yellow, orange or red?
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0answers
33 views

How much time does it take in Earth to generate the energy supply that the sun produces in one second?

According to this article which I ignore if it's correct The amount of energy the sun emits every second is , the amount of energy the sun emits by second is 4x10^33 ergs . And according to this other ...
-1
votes
2answers
43 views

Sun-path on the sky [duplicate]

We are standing on the Earth and we see Sun on the sky. We see it walking in a certain direction, with predictable moving. Earth is a spheroid, as we all know. It is circling around the Sun, and also ...
1
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1answer
50 views

Would the effects of a Coronal Mass Ejection be magnified in the South Atlantic Anomaly area?

The South Atlantic Anomaly is an area where the Earth's inner Van Allen radiation belt comes closest to the Earth's surface, dipping down to an altitude of 200 kilometres. This causes one of the ...
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1answer
35 views

Do coronal mass ejections and solar flares diffuse over long distances?

I understand that over great distances electromagnetic radiation such as light and lasers would diffuse greatly (much like a shotgun blast). Is this the same case for solar flares? If this is the ...
38
votes
7answers
7k views

Why does the full moon appear?

I know that the full moon appears when sun, moon and earth are in a straight line but if we consider that they are in straight line, why is the moon illuminated? I mean to say that earth should block ...
2
votes
0answers
67 views

Celestial Body Approaching Speed of Light, “Observed” as a Black Ellipsoid?

I have an interesting question, one which I think may not work haha, but please bear with me. Let's work with our sun, with mass of about $2 \times10^{30}$ kg. According to the following formula, ...
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0answers
37 views

Are the planets revolving around the sun in perpetual motion? [duplicate]

I was wondering if the planets revolving around the sun are an example of perpetual motion. Will they ever stop the revolution?
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votes
1answer
55 views

How to calculate the focal spot size of concentrated sunlight

I know that concentrated photovoltaic systems use Fresnel Lenses to concentrate incident sunlight to a point. I also know that this point isn’t infinitely small and has an actual size since the lenses ...
2
votes
1answer
43 views

Solar neutrino Spectrum - Why are there discrete energies for Be and pep?

What is the reason why some reactions give a continuum for the energy of the released neutrinos and others give only a discrete value ($\ ^7B$ and $pep$ )? Thanks for your help. Please feel free to ...
2
votes
1answer
26 views

What's the timescale for the formation of a coronal mass ejection?

How quickly does the sun form and release a coronal mass ejection? If we were watching the right part of the sun closely, how long would it take us to go from "nothing seems to be happening" to "...
0
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0answers
25 views

Hole in the ozone layer: Solar flare

Does the growing hole in the ozone layers lead to an increase of effects from a solar flare that emits radiation such as gamma rays and many other things?
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0answers
56 views

Estimating the temperature of the sun using Wien's displacement law

After previously deriving the frequency distribution of photons as $$u(\omega,T) = \frac{\omega^3\hbar}{\pi^2 v^3}\frac{1}{e^{-B K_B T} - 1}$$ I have been asked to estimate the temperature of the ...
0
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3answers
237 views

Is it possible to collimate a point source of concentrated light?

So I am wondering whether it would be possible to create an optical system that does and consists of the following: Use a Fresnel lens to concentrate direct sunlight to a point focus. I assume that ...
-1
votes
2answers
44 views

Extra figure in photo of sun [closed]

I just captured a photo of sun in my mobile camera. And see the pic. Where there is an extra sun or a shape similar to it just below on the right side. What is this?
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0answers
18 views

For how much energy does the heat generated in earth's interior account in earth's total energy budget? [duplicate]

I imagine the sources of earth's total energy budget to be The sun The sun deposits about $\sim 1400 \frac{\mathrm{kW}}{\mathrm{m^2}}$ via radiation on earth$^1$. Eventually, this is the source of ...
1
vote
3answers
308 views

Why isn't the Sun blue?

If I believe right, blue flames are hotter than red ones and if I recall correctly it's because blue tend to ultraviolet. Then why is the sun, which's capable of warming whole planets, red instead of ...
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votes
2answers
37 views

Do all materials get warmed by the sun, or do there exist materials which reflect the major part of the IR radiation?

Once upon a time, on a hot day, (in a country far, far away, where the internet doesn't exist) I was wondering when I felt that all things around me on which the sun shined were feeling warm: Do all ...
0
votes
1answer
57 views

Can a perfect Earth-sized lens between the Earth and the sun darken parts of the Earth (so in that parts the sky looks like the night sky)? [closed]

Suppose an Earth-sized (convex) perfect lens is placed between the sun and the Earth (with the center of the lens on the line between the center of the Earth and the center of the sun, and the lens ...
6
votes
1answer
116 views

Water molecules on the Sun? How does that work?

I've been reading about water on the Sun. The water they talk about is supposedly in a gaseous state because the Sun is so hot. But I'm wondering how even that could exist. Wouldn't the extreme ...