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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Magnetic explosions on Sun

They say (in popular videos and articles) that tangled magnetic fields on Sun explode. But i don't understand why and how magnetic fields, tangled or not, explode. Could anyone explain?
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What's the lifespan of Deuterium and Helium-3 in the Sun?

What's the lifespan of Deuterium and Helium-3 in the sun? How long on average, the Deuterium and Helium-3 atoms last in the Sun's core?
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How much energy holds the full visible light spectrum? Same to heat absorbed by back color?

I would love to know how much energy a black body absorbs from the visible light. In the following site we can calculate the eV of a given wavelength, but if I'd like to know the sum of eV for the ...
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How much energy from gravitatational waves does the sun absorb?

I was wondering how much energy from gravitational waves the sun could absorb since it is so big and also has a massive gravitational pull. Is it possible for the sun to trap gravitational waves ...
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How does the DKIST filter out photosphere light?

How does DKIST filter out light from the sun's photosphere while capturing light from the chromosphere? I'd like to know the physical or mathematical mechanics that accomplish this. If the naive ...
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How long before the Sun has given off enough energy=mass for a one meter thick Dyson Sphere at earths orbit?

Just for fun: As energy can be converted into mass - what if we had some kind of magic technology which can convert photons into carbon atoms with 100% efficiency. I realize its not as easy as just ...
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Why are sunspots cooler than the other regions?

The Sunspots appear darker than the other regions because they are cooler; and I know that according the Babcock model, the Sunspots are places where the tangled magnetic fields burst out through the ...
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How much energy from neutrinos does a Helium flash create?

How much energy from neutrinos is given of by a solar mass star when it undergoes a Helium flash?
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What percentage of sunlight isn't scattered by the atmosphere?

What percentage of sunlight isn't scattered by the atmosphere and instead will arrive at your eyes directly from the sun. It's been aksed here before but a proper answer hasn't been given. I was ...
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What exactly is the "Yield Function" of a neutron monitor?

I have been reading papers related to the theoretical computation of a neutron monitor count rate, which is defined as the integral of the "yield function" of the specific neutron monitor ...
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Does the RA and DEC of the sun change with time?

I'm almost certainly misreading this, but it's said that "one of the great advantages of the equatorial system is that the RA and Dec of a star do not change with time, at least over short ...
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What effects would a substance as hot as the sun have on its surroundings on Earth? [closed]

If you had an object, about the size of an adult human, that was as hot as the surface of the sun that somehow doesn't cool down, what effect would it have on its surroundings? Would it just vapourise ...
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On average, how often does any given hydrogen nucleus run into another hydrogen nucleus in the Sun?

I think there is a misprint in an article. I will include the link if you don't mind and cut paste the sentence that I think is a misprint. Here is the link https://www.abc.net.au/science/articles/...
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How much is the UV index reduced when under the shade approximately?

Assuming simple conditions e.g. sunny, bright day (no clouds), sun is directly overhead, what becomes the effective UV index for someone who is outdoors under solid shade (e.g. sitting under a ...
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Is the total gravitational energy in the sun greater than the energy that is produced by the sum total of the nuclear fusion contained therein?

I think this is off topic, maybe an astronomy question. Unlike a chemical chain reaction or a fission chain reaction I believe fusion cannot sustain inself. Is more energy going out than is going in ...
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Does dusk really remain for a shorter period of time at the equator?

It is said that the dusk remains for shorter time at equator than the poles. Because, the equator rotates faster than poles. But it is also true that time is the same in every latitude, and if it's ...
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Absorption spectrum of white light of the Sun

When some photons in the white light from the sun are absorbed, this means some wavelengths will be missing, so how does that light still appear 'white', although some of its constituents are missing?
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How exactly does one reaction of nuclear fussion exactly produce EMR of different types? [closed]

Electromagnetic radiation from sun is more likely produced by the nuclear fusion, and at a go radiation is released but how is it possible for different types of radiation to be produced such as, ...
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How to calculate amount of energy an area receives from sunlight?

I recently read this article, but is quite unclear on how it got those equations and used them to find the amount of energy (J) an area receives from sunlight over a period of time (s). Does anyone ...
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Do solar flares move the dust on the surface of the Moon?

The TV show For All Mankind has a reputation for scientific accuracy, so I think it's fair game to ask if it lives up to this reputation. In this video clip, we see the dust on the surface of the Moon ...
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What is the minimum size of an object to cast a shadow on the entire Earth?

When I fly up(don't ask me how), I see how my Sun's shadow on Earth is getting bigger but dimmer as the Sun's light is reflected from other objects. As I flew higher and higher in the direction of the ...
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Does the index of refraction of the sun's corona and solar wind contribute to the bending of light

It's not hard to imagine that the sun's corona and surrounding solar winds have an optical density that can affect the index of refraction near the surface of the sun and bend light in these regions. ...
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Is there any clear and concrete proof that says the Earth is rotating and orbiting? [duplicate]

As the title states, I am wondering if there exists a clear and concrete proof that proves that the earth is revolving around the sun on an orbit, and proves that the sun is not revolving around the ...
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Earth is spiraling away from Sun at rate of 1.5cm per year due to mass loss of Sun? How it was calculated? [closed]

My physics teacher asked if we could calculate the rate at which Earth moves away from the Sun due to the mass loss of the Sun. It's very sensible for me to understand that Earth is spiraling away ...
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How is the solar magnetic field produced?

I have been trying to understand the magnetic field creation mechanism. I know that its origin is not perfectly understood, but what is currently believed (as I know) is that the magnetic fields ...
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Temperature and latitude

Currently I read this excerpt on a school power point that stated the following: " The sun is closer to the equator than the poles. Therefore the sun’s rays have less distance to travel to the ...
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Have solar wind particles escaped the Sun's gravity or will they eventually return back?

I've read that solar wind consists of hydrogen atoms that are, near the Earth, travelling at about 450 km/s. This is only 3/4 of the Sun's escape velocity, but then the Earth is also 150 million km ...
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Black body side of the Moon

A few closely related questions regrading the Moon thermodynamics: The Moon is clearly not a black body, as it reflects a great deal of radiation incident on it. Still, it does absorb some radiation ...
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Does pressure increasing or decreasing due to temperature have an impact on the Sun Core's "Thermostat"?

Firstly, thank you for reading this post. I have a question regarding how the Sun regulates its nuclear fusion rate in its core. This is commonly known as the Sun's thermostat. This is a homework ...
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Colours of the sky if sun was blue?

What would be the colours of the sky at different points of the day if the sun was a blue star? This is assuming that our earth is at a similar distance away from the surface of the blue sun as it is ...
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How much percent of the speed of rotation of the solar surface at the equator is due to frame dragging effect? [closed]

Frame dagging effect is interesting and my particular interest is does this rotation could be compared with the law of motion of planets in a system similar to our Solar system and also can we measure ...
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Building orientation - how come both summer and winter solstice used for a facade?

I am planning to build a shed atop my terrace. I was analyzing the sun path to determine the overhang length, facade height etc, but got stuck with a conflict as below. The summer sun's location peaks ...
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Is Thermal radiation emitted by a blackbody some photons

If a blackbody absorbs all radiation and emits some due to it's heat, then is the thermal radiation actually some photons that are not in the visible region? Can there be a blackbody that emits ...
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Long temporal coherence sunlight

What is the reason that sunlight have short temporal coherence? I know everybody says that coherence length is inversely proportional to bandwidth. Does it mean that if sunlight passes through a very ...
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How do objects emit light?

I recently bumped into a question of how things emit its color. And I've gone through some articles on the internet to be now stuck between two phenomenon: reflection (I'm not sure if its called this ...
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Radial dependence of temperature of solar wind?

How does the temperature of the solar wind plasma depend upon radial distance from the Sun?
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Where do the Neutrons for fusing Hydrogen to Helium in the Sun come from?

The sun works by fusing hydrogen to helium (at the moment). While hydrogen is a single proton (I'm ignoring electrons here... not sure if they are relevant since it's probably a plasma anyway) helium ...
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Why does the "edge" of the sun appear red first?

During sunset, I have noticed many times that the Sun's outer boundary becomes red first but the middle part is yellowish by that time and then after some minutes the whole sun becomes red. Now I have ...
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Law of amount of interference between different Sun rays that fall on a distinct point on Earth?

The double slit experiment shows that rays comming from different locations can cancel each other when touching a point on a screen if they are out of fase because of their wave properties. Is the ...
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Can we witness Optical illusion in which sun appears to set in mid sea than at horizon?

I was searching for optical illusions and came across a video on youtube where sun seems to set in the mid of sea instead of setting at the horizon? Can anyone please explain how this illusion takes ...
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Lag in Direction of Earth-Sun Gravity vector

When the earth is orbiting around the sun, it experiences a force vector pulling it towards the sun, which acts as a centripetal force for its elliptical orbit. However, when the earth moves a bit ...
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How small/large can a sun/star be?

I have zero knowledge about astronomy (I often mistake it with astrology) so my question might be a bit naïve. But what are the limits for stars to be stable? I guess you can't up or downscale our ...
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In which direction do the perihelions of the planets show? Is this somehow correlated with the solar apex?

I just found a Wikipedia page that showed that almost all perihelion where at the same position (except for Mars) and I was wondering, if someone has more information /data/pictures. Thank you!
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How far should I be from my screen to get a crisp image?

I want to use a flat mirror to create a projection of the Sun. My mirror is 3 by 1.75 inches (5.25 squared inches). How far should I be from my screen to get a large crisp image?
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What volume would the mass of Earth occupy in the core of the sun?

I was just wondering if anyone had computed this. I read that the pressure in the Sun's core is 3.84 trillion psi. Obviously the mass of an Earth-sized object in the core would be millions of times ...
1 vote
1 answer
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What is the Hydrogen and Helium composition of the Sun in terms of their different states?

What is the Hydrogen and Helium composition of the Sun in terms of: Hydrogen: (1) molecular, (2) metallic and (3) ionized compositions? and Helium: (1) atomic, (2) metallic and (3) ionized ...
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Do sunrises and sunsets look the same in a still image?

A question that popped into my head: if I see a picture of the sun close to the horizon, in an unknown place, can I know if it was taken at sunset or sunrise? Do sunrises and sunsets look the same in ...
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Was Eratosthenes justified in his belief the earth was round? [closed]

Because I see two flaws with it, firstly he assumes the distance of the sun won't affect the angle at which light hits the pole. If the sun were far closer and far smaller, there would be a change in ...
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Are new Moons (and full Moons) more probable to happen around certain ecliptic longitudes?

The average lunar synodic month is 29.53059 days. Because of these variations in angular rate, the actual time between lunations may vary from about 29.18 to about 29.93 days. The average duration in ...
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4 votes
2 answers
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Plage regions data

Plages are phenomena of stellar activity. Where can I find openly-accessible data of plage regions of the Sun with other parameters such as faculae region, magnetic field, etc?

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