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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1answer
40 views

What effect does color on the upper and lower side of umbrella have?

This question isn't referring to the general use of umbrella to provide protection from rain rather it concerns the optical effects of the color on lower and upper portion of umbrella. Umbrella are ...
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Finding how much time it takes for a complete Earth revolution around the Sun

Long story short, my brother made a joke about how stupid it is to celebrate the Earth making one "trip" around the Sun: New Year's Eve. So I got curious and was wondering: how could the first ...
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How is a horizontal sunset possible? [closed]

Source: @PHSXES/Reddit Normally, sunset moves vertically, from up to down in the sky. But in this photo, it appears to be moving horizontally, from left to right. It might be an instant of a ...
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Solar panel and Equinox

At Equinox the number of hours of daylight and night is equal so 12 hours of each... is this from 6am to 6pm? how can we know which hours this daylight happens for. The question is: Over which ...
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Why doesn't the Sun gravitate Mercury so that in following years, Mercury goes inside the Sun? [duplicate]

There has been news in public about Mercury that passes in front of Sun which happens very rarely every 100 years, here. So people on Earth can see it through special kind of telescope, of course, ...
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Units in Representation Of Energy Density Spectrum

In most of the texts, I referred to The Axis being labelled with Units as shown above. But I also found few images with different Notation (1/Units) Being Followed as shown Below. The units of the ...
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3answers
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Do rainbows show spectral lines from the sun?

I'm aware of a similar question being asked in Do rainbow shows spectral lines?: The response to this question is that the body producing the light is not the water droplet that merely diffracts it ...
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How can I sample the solar spectrum to determine, in the vacuum of space, the frequency of a random photon?

I am working on improving a spacecraft charging model by simulating the photoelectric effect. To do so I need to determine the frequency of a random photon coming from the sun. How would I go about ...
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2answers
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Could a foggy double-paned window be amplifying UV rays?

Ever since my living room double-pane window got foggy, I've noticed that I feel very uncomfortable/sick when it is a very sunny day (similar to the way I feel when I've been out for too long in the ...
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1answer
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Solar astrophysics--flux derivation [duplicate]

The question reads: The solution reads: My only answer is for 4 and it is $\pi I_\nu$. Where did I go wrong?
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Superman threw a net with a lot of nukes into the Sun. What happens now? [closed]

The iconic scene in "Superman IV: The quest for peace" shows the eponymous character throwing a net filled with nuclear missles into the Sun. If that were to happen in real life, what would happen as ...
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Sunrays through clouds paradox [duplicate]

So I have a layman question. If we look at the angle of the sun rays, doesn't sun seem much closer than it is [150 million kilometers] cant we take those angles that the sun makes with the earth, ...
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How does the Sun warm a person? Is it convection, Conduction or Radiation? [closed]

I know that heat transfer can be conduction, radiation or convection, but I don't know which one it is.
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How do I calculate the relative number of photons per wavelength emmited by the sun?

Assume I generate $n$ photons emmited by the sun. They have wavelengths between 390 and 750 nanometers. How do I find out the number of photons that correspond to each wavelength: How many of my $n$ ...
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1answer
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Gravitational field of sun [closed]

Let there be a solar system without Earth. Now what happen if we place the Earth suddenly on its actual position does the gravitational force of sun acts on it immediately because of its pre ...
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Sun’s corona is so much hotter than Chromosphere [duplicate]

What makes Sun’s corona so hot? I tried to google it but can’t find satisfactory answer.
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1answer
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Is there a way to see the sun's outer layers from earth outside a solar eclipse using polarization?

¿Is there a way to filter sky light using light polarization? in https://en.wikipedia.org/wiki/Coronagraph#Invention it says: High Altitude Observatory's Mark IV Coronagraph on top of Mauna Loa, use ...
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1answer
199 views

How is the constant “284” derived within the Solar Declination Angle equation?

How is the constant "284" derived within the Solar Declination Angle equation? The earth's axis results in a day-by-day variation of the angle between the earth-sun line and the earth's ...
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1answer
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How thick would the atmosphere have to be to block all the sunlight?

this is a question I haven't been able to find an answer to anywhere. How thick would our atmosphere have to be for the surface of the planet to be completely dark? Is that even possible? Thank you!
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1answer
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Formation of Red and blue bands in the sky

Today at the time of sunset I saw this The sky is divided into two parts one In red and one in blue which are very distinctive Can anyone tell how? The upper part of the image points towards the ...
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2answers
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How can Sun burn in space?

If there is no oxygen in space how can sun burn in space. (even though I know fire is caused by nuclear reaction inside sun)
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Do solar energetic particles follow the Parker spiral?

I understand that the solar wind follows the Parker spiral shape of the Sun's magnetic field, thus it is possible for solar wind from a point on the opposite side of the Sun to reach Earth. I have ...
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1answer
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Why is the Sun made of light elements only?

Since the entire solar system inherits its heavy elements from supernovae unrelated to our star, I fail to understand why, while capturing most of said system's matter, the sun only contain light ...
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Luminosity of the sun

How is it that the total power generated by nuclear reaction in the core of Sun exceeds its total luminosity? Where does the difference go?
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1answer
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Will the Sun's orbit around the Milky Way degrade once it transitions to a white dwarf with half its original mass?

Does the Sun's mass factor in at all when it comes to its orbit around the Milky Way, such that if it lost half its mass, its orbit would change? Or is it a matter of the center of the Milky Way being ...
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Why the gravity of a black hole is so strong by the Bad Astronomer

In this bad astronomer video, Phil Plait says two things: 1) He first demonstrates the effect of gravity using paper, and he keeps a fixed mass and distance. However as he makes the paper smaller and ...
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Is the surface temperature of the sun constant?

I was just wondering that during the suns mains sequence would it maintain a constant temperature at the surface and only cool once the hydrogen in its core runs out, or is it always slowly decreasing?...
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Calculation of the temperature of the Sun's core? Why is this value so low?

From the Stefan-Boltzmann Law ($j^*=\sigma T^4$), the luminosity of the Sun is $L_{sun}=j^*A=[\sigma T^4][4\pi R_{sun}^4]=3.85\times 10^{26}$ W. If I assume the Sun to be in a steady state then the ...
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851 views

Is an obsidian plate safe to use as a Sun viewer? [closed]

Is a 0.5 cm thick obsidian plate good to see the Sun directly?
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1answer
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Can RGB screen color exist in real physical world?

For example the bright royal blue color; R0 G10 B220, HEX: #000ae1. I know this color cannot be printed nor painted. But can this blue color exist in the real world other than on a digital screen? For ...
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2answers
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Size of iron sphere with mass of our sun [closed]

What would be the diameter of a sphere of iron with the mass of our sun? Use standard density of metalic iron. I realize it would then collapse into a star in its own right and become much smaller as ...
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1answer
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What exactly is delta-14C and why are there periodic plateaus in the delta-14C curve?

I downloaded the IntCal13, IntCal09, and IntCal04 datasets (parent site), and when I plotted the last 24k years was surprised to see a plateau or even reversal appear every ~5300 years. Apparently we ...
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Where is nuclear fusion occuring in the Sun?

My understanding is that the sun is basically a sphere of hydrogen with a helium core, and that the hydrogen is undergoing nuclear fusion to produce helium. There are many images and cross-sectional ...
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Radius of the Sun

Is it possible to calculate the radius of the sun with minimal amount of physics? I couldn’t find resources on the internet that gives me an answer using a theoretical formula. You are given values ...
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What is the reason for the emission of electromagnetic waves from the sun? [duplicate]

What is the reason for the emission of electromagnetic waves from the sun and why curve its in about the visible light is maximum?
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2answers
93 views

How much change in Earth's orbital distance to change average temperature by 1°C?

How much closer/farther would the Earth need to be to/from the Sun to effect a $1 \sideset{^{\circ}}{}{\mathrm{C}}$ increase/decrease in average temperature?
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3answers
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Is there a difference between the red sky in the morning and in the evening?

It certainly has a different feeling to it, but does the temperature or earth's rotation or the clouds or anything else really make it two different physical phenomena or at least different colors? ...
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1answer
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How much does time-dilation effect our observance of the most massive objects in our solar system?

Disclaimer: I'm kind of a newb, so I apologize if this question is not well formed. Please comment if anything is unclear, and I will do my best to make corrections. Reading this post about time ...
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1answer
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How many times do solar protons repeatedly fuse and fission before they form deuteron

In the proton-proton chain reaction in the Sun, the first step is $$p + p \rightarrow \; ^2_2{\rm He} .$$ After this, the most likely thing to happen next is that the reverse reaction occurs: the $^...
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1answer
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If the Sun had a larger surface temperature how would that affect its appearance to us in the sky?

I thought about this when I came across wiens displacement law which says the higher the temperature, the lower the peak wavelength. If the sun was a lot hotter, and its peak wavelength wasn't in the ...
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1answer
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How much does temperature affect the time of sunrise?

Please forgive me if this is a dumb question, or if my understanding of basic physics is wrong. Please feel free to correct me. As I understand it, if the Earth didn't have any atmosphere, then the ...
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What is angle between ray to center of the sun and its perimeter?

If I took a ray from a point on the earth P to the center of the sun. And another ray from the same point on the earth to the perimeter of the sun. What would the ...
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1answer
174 views

Will a black body placed somewhere around the Sun obtain (eventually) the same temperature as the Sun?

Suppose we look (above the Earth's atmosphere) at the wavelength ($=\frac c f)$ spectrum emitted by the Sun: This shows that the Sun is approximately a black body with a temperature of about $5525(K)....
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Question about China's Artificial Sun

I have read recently in many websites dedicated to science that China has made an artificial sun hotter than the 'sun'. My question is how did they make a thing that can withstand such a high ...
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1answer
60 views

How does the Earth's radial acceleration affect it's velocity during orbit around Sun? [closed]

When the earth moves along its ellipse at $67,000mph $ it accelerates at $0.006m/s^2$ would it be correct to say it's speed at some points relatively increases by $0.006m/s$ every second
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1answer
113 views

What's the Earth's linear acceleration component around the Sun?

The earth's centripetal acceleration around the Sun is $0.006m/s^2$ does this mean one can say the earth's acceleration when it travels(revolves) at $670,000mph$ is simply equal to its centripetal ...
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How does brightness affect color? [duplicate]

How does brightness affect the color of light? For instance, the sun might be yellow because of the blue scattering when the light travels through the atmosphere - but if you look at it, it seems ...
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2answers
117 views

Why does the sun always have some whiteness? [duplicate]

So the atmosphere scatters light on its way to earth, making the color of our sky. For example, when the sky is blue on a clear, sunny day, the sunlight appears somewhat yellow because the blue light ...
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1answer
42 views

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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1answer
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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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