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Questions tagged [sun]

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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What is the incident power of the sun for different parts of the U.S over time?

I have seen number as low as $200\ \text{W}/\text{m}^2$ to $1000 \text{W}/\text{m}^2$. I'm in California and looking for information on how much power my solar panels will pick up. I have $4100\ \...
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Is the Earth orbiting an 'illusory' Sun, owing to the 'speed' of gravity? [duplicate]

We see the Sun about eight minutes after light left it. Presumably this means we are also experiencing the Sun's gravity 8 minutes after it 'left' the Sun. So are we orbiting around the Sun we can ...
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Does the sun have nonzero electric charge? [duplicate]

The sun is a star, meaning it's a ball of gas undergoing nuclear fusion in its core. The sun, like any other star, experiences line-driven stellar winds due to the transport of ions from its interior ...
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How does the energy of a solar flare propagate?

Does it radiate outward, spherically, or is it more directed? Is there some opening angle? Is it more complex than this?
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What's the eccentricity of our sun's orbit around the center of the galaxy? [duplicate]

Just thinking about "galactic habitability zones." Is this even a valid question?
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How massive is the Sun compared to other stars?

I was just reading "Rare Earth" by Peter Ward and Donald Brownlee and they claim that $95\%$ of stars are less massive than the Sun. But, I was always told the Sun is an average star. Which is it?
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If the Earth would change into a ball of water, how wil its form develop, considering only the Sun's and Moon's influence? [duplicate]

Let's fantasize that the Earth changes in a non-rotating ball of water. And let's assume the only gravitational influences on it are those of the Sun and Moon. What will happen to the form of the ...
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How much would the lifetime of the sun change if the reactions inside ended at 3-Helium

This is assuming no other changes. I am aware the PPI branch makes up 87.1% of the reactions in the sun, and that the PP sequence as a whole powers the sun, but I am not able to tell the amount of ...
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How to calculate weight of an object orbiting another object?

How do we calculate weight of an object which is orbiting another bigger object in the space? For example, comparing the pair of Sun-Earth, Earth is orbiting Sun due to the force applied by Sun on ...
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Watts in the brightness of a Full Moon

I heard that there is a order of magnitude of brightness/luminosity for a full moon, roughly 398110 times less than the luminosity of the sun. And the luminosity of the sun to watts is 3.846 x 10^...
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Gravitational/electromagnetic effect of planets on solar activity?

Does the gravitational and/or electromagnetic influence of planets have any effect or correspondence to solar activities (e.g. solar flares/CMEs) - and if so, does the planetary position (where they ...
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Why are clouds lighter than the sky during the day but darker at night

This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during ...
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Microwave radiation levels

what is the strength of microwave radiation reaching the earth's surface on an average day, measured in Watts?
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Triangulating Sol's position from another star

Let me pose this question as a hypothetical. Your ship makes a warp/jump through space. There's a malfunction. You're definitely not at your intended destination. You've warped to an unknown star, ...
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44 views

Living at the equator (Colombia), how to figure out the orientation towards north using the sun falling through a window?

The real life issue is this: A friend is moving to a new apartment. What is bad here, is if the apartment is getting full sun in the morning or afternoon. So the Sun goes from east to west, right? If ...
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Ray sun heating

I recently got a curious question about the sun rays. Is there a material that can absorbs most of them and turn it into pure heat? For example, we all know that dark material (black t-shirts) get ...
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Why are there dark lines in an absorption line spectrum from the Sun? [duplicate]

Consider this image and quotations from Basics of Radio Astronomy for the Green Bank Telescope: When a continuous spectrum is viewed through some cool gas, dark spectral lines (called absorption ...
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1answer
114 views

What would happen if gamma-ray burst from a supernova burst hit the sun? [closed]

What would happen if gamma-ray burst from a supernova burst hit the sun? Would the sun explode? Would the sun expand. Have a longer lifetime? Shorter Lifetime? Because people are nit-picky about stuff ...
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What is meant by “stable/unstable to convection” in the context of the solar atmosphere?

In studying the Schwarzschild stability criterion (for the solar atmosphere); $$\left\lvert\frac{dP}{dr} \right\rvert\lt\frac{\gamma P}{\rho}\left\lvert\frac{d\rho}{dr}\right\rvert$$ From my notes are ...
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4answers
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Is there any way looking at Stars from that I can understand that we are revolving around the Sun?(Not caring about other planets for now)

I am learning Astronomy. I videos or lessons I look at are already biased over heliocentric math to explain the parallax concept. I am looking for an intuition to get myself a deeper understanding of ...
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2answers
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Is the reason the sunshine is 'extra bright' after rain due to refraction of the additional water in the air?

Quite frequently after the sun comes out after rain I experience a 30 minute period where the sunshine is 'unusually bright'. Such that it makes my eyes water. My question is: Is the reason the ...
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1answer
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Why does the gas in Sun's outer layer not expand?

Since in the outer part of sun it consists gases. Why don't the gases expand due to heat? This was asked by my friend. And he said that the gases are attracted by the plasma layer by a force. So the ...
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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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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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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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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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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 ...
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1answer
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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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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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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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126 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 ...
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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?
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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 ...
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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 ...
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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?
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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 ...
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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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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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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 ...
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3answers
82 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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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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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 ...
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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?
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4answers
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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 ...
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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 ...
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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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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 ...
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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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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, ...
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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 ...