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 heaviest element being produced in Sun?
Helium is being produced currently in Sun. 3 questions.
Other than Helium what other elements are currently being produced in Sun right now.?
Looks like in 5 billion years, when Sun will become a ...
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1answer
48 views
Why sun rays are parallel despite so much atmospheric refraction?
Why we consider sun rays approx parallel although so much atmispheric refraction?
Whose refractive index keep fluctating due to layer of atmosphere thus one ray that take a path is not necessary for ...
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9answers
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Are the physical structures in our sun of comparable complexity to those in the human brain? [closed]
The writings of Rupert Sheldrake tend to provoke strong emotions, be they ridicule, curiosity, outrage, sympathy, disgust, or otherwise. While Physics SE is not an appropriate forum in which either to ...
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0answers
38 views
Why does the sun not burn your retinas when in peripheral vision?
After going to the ophthalmologist and having bright lights shone in my eyes, I was thinking about how the brightness only hurts when I looked at the light. When it was in my peripheral vision, it ...
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4answers
5k views
How to identify if a photon comes from the sun?
Is there any way to know whether a group of particles is generated from the sun rather from an artificial source?
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1answer
44 views
Is it a coincidence that distance between Sun and Earth=(Distance between Earth and Moon)*(365.25+24) or is there any logical reasoning behind it? [closed]
Here $365.25$ days is the time taken for Earth's Revolution around the Sun while $24$ hours is the Earth's rotation.
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0answers
41 views
If a black hole with an event horizon of 1 cm were placed in the Sun core what would be the Suns' lifespan as a visible star? [duplicate]
If a black hole with an event horizon of 1 cm were placed in the Sun core what would be the Suns' lifespan as a visible star? I want to get a visualisation of how much mass per second would be ...
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1answer
36 views
Could the sun be used as a particle accelerator?
Large particle colliders require a lot of energy, and inputing more and more energy usually produce more and more interesting results.
Assuming that the required collider, detectors, etc. can be ...
2
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2answers
126 views
After the discovery of the “unicorn” black hole, how likely is the Earth to be hit by a blackhole?
We know that the earth's chances to be hit by a blackhole before the death of the sun were practically 0 but how do the odds change after the discovery of the unicorn?
About the unicorn:
https://www....
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1answer
37 views
Damage from the Sun on a Raspberry Pi Camera Sensor with a Fisheye Lens
I'm working on a CubeSat mission which uses two Raspberry Pi V2 cameras (without special filters) as sensors. I am trying to estimate if they could suffer thermal damage if they were to have the Sun ...
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1answer
74 views
How much of the Tidal Energy can be attributed to the Sun?
I'm been researching this question but haven't been able to find a conclusive answer. As I understand it, there are two forms of tidal energy: tidal potential energy and tidal current energy. Tidal ...
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0answers
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Why at sunset the sky looks like a rainbow?
Why at sunset the sky looks like a rainbow?The higher part looks blue then as we look lower and lower we see white, yellow, orange and finaly red...as in the picture. Why the red light is so much ...
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1answer
36 views
What is the name for the instrument to measure radiation consisting mainly out of a glass ball?
I remember vaguely a measurement instrument to protocol probably solar irradiance. The instrument mainly consisted out of a glass sphere and if I recall correctly, the sun was "writing" ...
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0answers
21 views
Why the blue component of the moonlight is less scattered in Earth's atmosphere than the sunlight?
Why the blue component of the moonlight is less scattered in Earth's atmosphere than the sunlight? So when rising one of them looks yellow and the other red. Is this only matter of their brightness ...
9
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1answer
442 views
What are the physical processes involved in feeling warm from the sunlight?
Suppose a human is lying on a beach. He/she starts to feel warm after exposing his/her skin to the sunlight. I assume that feeling is due to the ability of the human body of "measuring" the ...
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0answers
16 views
Quantification and qualification of total solar electromagnetic output from Earth's perspective
I've tried tracking down the specifics, but this article mentions that the total energy output that Earth receives from Sol annually is ~430E18 J. The article links back to the US Department of ...
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2answers
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Why does the Sun appear white through clouds?
Why does the Sun appear white through clouds? It seems there should not be any absorption of, say, the reddish component, as this would not produce a white colour. So what is going on? Am I right that ...
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4answers
123 views
How can the mass of the sun be determined without using Kepler's law or gravitational lensing?
Can the mass of the sun be determined using the abundance of elements or alternative methods? It would be better to ask the question like this if we assume that I have an object that contains baryonic ...
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0answers
14 views
How much of the Sun to not evaporate is due to gravity and how much due to magnetism?
As protons and electrons on the sun 'surface' have high kinetic energy something obviously should stop them to go away.Its gravity is very high compared to planets but is this enough as magnetism also ...
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0answers
25 views
Why is the Sun's surface a good example of grey atmosphere?
I'm approaching the study of elements of Astrophysics, and the teacher, while speaking about the grey atmosphere model, said that for the Sun's surface the model is a good approximation of what ...
3
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2answers
216 views
Effects of time dilation on our observations of the Sun
Forgive me if this question makes little sense -- I'm not a physicist, only an interested observer.
As I understand it, time is dilated in gravitational fields and the stronger the field the stronger ...
2
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3answers
101 views
What would happen if all protons in the Sun had a charge of 1.000001 times the elementary charge?
The whole sun would be positively charge, but would it explode because of it? Or would it just expand a bit?
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0answers
37 views
Is the Sun losing mass and pushing the Earth further away? [duplicate]
With the sun radiating so much energy every millisecond can nuclear fusion keep up with that pace? And if it can’t keep up isn’t the sun losing energy every second and therefor losing mass? Which ...
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0answers
41 views
Why is our sun yellow in color? [duplicate]
We know that sunlight or light incident from sun on earth is white in color or have all frequencies of light in visible electromagnetic spectrum.
However I have read that sun is a yellow medium star, ...
0
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1answer
44 views
How can i analyse this motion?
Hello
(Im from south Korea. im sorry for my english in physics.)
im curious about this gravitational spiral motion.
can its trajectory and time took to collide be guessable? or can i calculate this ...
0
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1answer
44 views
Why do helium fuse in the Sun?
Initially there are lots of hydrogen atoms and trace elements in the Sun. Despite insufficient energy for the hydrogen to fuse in the core, quantum tunneling saved the day and invoke proton-proton ...
3
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2answers
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Basic questions about Alfven waves in solar corona
I'm a mathematician trying to understand a paper in mathematical physics (Alfven Reflection and Reverberation in the Solar Atmosphere, by Paul Cally), and although I understand most of the pde theory ...
3
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2answers
95 views
If the sea surface were absolutely calm should the Sun reflection be the area of a circle instead a ribbon?
Although waves produced on the sea can cause different points of the sea surface to reflect sunlight towards the same observer, how is that kind of ribbon image produced? Why isn't the reflection ...
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2answers
48 views
Spectrum of stars
How does the spectrum of F type stars differ from our sun? I have tried to find the information on the internet but I haven't found anything that helps me. I need the information for a novel I am ...
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1answer
41 views
Cause of seasons
NB: I live in the northern hemisphere so when I say summer and winter I'm referring to ~July and ~January respectively.
I've been reading online about the cause of the Earth's seasons and I'm still ...
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2answers
156 views
The role of the Sun in spring and neap tides
I am trying to understand how the Sun affects tides on the Earth's oceans and seas.
It is quite clear that when the Moon is in the first and in the third quarter, the Sun's and the Moon's ...
1
vote
1answer
161 views
How does light look like when it is 180° out of phase? [closed]
When two lights are 180° out of phase, would it look like this?
In the photo below, the left side is flipped and it is a mirror image.
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1answer
72 views
Why is the Sun the centre if relativity is true? [duplicate]
I thought a bit about this, and got confused as to why we always claim the Sun is at the centre of the solar system since relativity tells us that there is no preferred frame of reference. A person ...
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1answer
111 views
The temperature of the surface of the sun
If I calculate the temperature of the Sun by replacing the effective frequency of the Sun (598 THz) in Planck's curve for Blackbody radiation, the result will be 10170 K. Still, in Wien's ...
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2answers
94 views
In the difference between the sun and moon's tidal effects on earth, is density or distance a larger factor?
This question is inspired by the (now looking at it, improper use of, my bad) comments section here in Physics SE. I'm not sure I could explain better than our short discussion does below:
No, the ...
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4answers
2k views
Do photons slow down this much in the Sun's gravitational field?
I just heard someone mention that photons take 40 thousand years to travel from the centre of the Sun to its
surface which is roughly 700,000 kilometres. How is that possible if the speed of light/...
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1answer
78 views
Kepler's third Law
Kepler's third law states $C=\frac{r^3}{T^2}$, as seen from the orbits of planets around the sun. But as the earth also attracts the sun, the sun must also orbit the earth and so $c=\frac{r^3}{T'^2}$ ...
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3answers
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What is the origin of the Sun light?
The Sunlight is an electromagnetic radiation.
Is it known what is the origin of this radiation? Can it be adequately described by classical electrodynamics (Maxwell's equations) as a motion of ...
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1answer
86 views
How to calculate Night Flight time during a flight? [closed]
I am currently working on a web app (Pilot Logbook) that requires a user to automatically calculate the period of flight spent in the night.
Currently, I have
Departure Lat and Long and Departure ...
0
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1answer
44 views
What are the sources of error in the formula I derived to estimate sunrise and sunset times, and how can I improve its accuracy? [closed]
I derived the following formula to estimate sunrise and sunset times:
$$ t=\pm\cos^{-1}\frac{\sin\theta-\sin L_{loc}\sin L_{sun}}{\cos L_{loc}\cos L_{sun}} $$
$L_{loc}$ is the local latitude
$L_{sun}$...
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1answer
30 views
Do switchbacks occur in the radial direction of the solar wind magnetic field?
My question is:
When we are talking about switchbacks, do we mean switchbacks in the radial component of the magnetic field or in the total magnetic field?
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1answer
28 views
Why do we sometimes refer to the solar wind as young solar wind?
Why do we sometimes refer to the solar wind as young solar wind? What does young imply?
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1answer
35 views
Measuring Sun and Moon distances to the Earth ratio just by observing angles of elevation if upper 50 percent of Moon's surface is bright?
When the next type of calculation was possibly used for the first time? If 50% i.e. upper half of Moon were bright would the Sun-Earth to Moon-Earth distances ratio be calculated from just ...
2
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1answer
17 views
Does the sun's electromagnetic field disrupt communication?
If you were to design a drone or probe that could fly close enough to the sun to examine the corona, closer than the Parker Solar Probe, how close could you get and still have reliable communications ...
1
vote
1answer
43 views
What is the amount of mass ($\rm kg$) that the Sun loses daily in the irradiation form?
I had difficulties to post my question because the system asks me to detail my need more.
Is it necessary?
Doesn't my question make sense?
There is no need to answer, I just want to know if there is ...
0
votes
1answer
35 views
Are there any effect of Sun to the tide? [duplicate]
The Earth is rotating for the Sun's gravitational field. Like a free falling object Earth should feel zero gravity to the Sun. So why there are effect of Sun to the tide?
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0answers
28 views
How much does the sun emits in the radio spectrum, compared to artificial (human) emissions?
I would like to compare natural vs artificial (human) emissions in the radio spectrum (f < 1 THz).
The goal is to bring some scientific facts in the debate for deployment of 5G.
It's easy to find ...
9
votes
3answers
922 views
Why does the solar corona appear white?
Look at this photo taken in France during the 1999 solar eclipse which I found on Wikipedia. Why does the corona appear white? It has a temperature of about $10^6\,$K so you would think that it would ...
0
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1answer
127 views
Pool cover efficiency of absorbing and retaining heat in pool water
Looking into the options of adding and retaining heat in the outdoor pool (and saving wallet) - heat inverter, roof solar water heater, gas heaters etc. the pool cover seems to rule them all (at least ...
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2answers
58 views
Problem regarding the absorption spectrum of the sun [duplicate]
Some of the wavelengths of light that are emitted from the sun will be absorbed by atoms in the outer layer of the sun and also the atmosphere of the sun, and we see this as absorption lines in the ...
