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 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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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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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, ...
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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 ...
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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 ...
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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 ...
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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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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
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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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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 ...
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1answer
151 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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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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92 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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66 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
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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
65 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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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
83 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 ...
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1answer
42 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
25 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
31 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 ...
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1answer
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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 ...
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1answer
40 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 ...
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1answer
34 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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23 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 ...
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3answers
907 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 ...
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1answer
31 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
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Problem regarding the absorption spectrum of the sun
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 ...
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Why Sun's coronal belt is more stable at Sun's equator?
As the Sun's coronal belt is made up of protons and electrons constantly scattered by photosphere's sunlight and as these particles are forced to do loops due to Sun's magnetic field is it possible ...
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3answers
112 views
Why does the spectrum of Sun follow a black-body distribution curve?
Black-body radiation, as I understand it, is radiation in thermal equilibrium at a fixed temperature with a cavity. The spectrum of such radiation follows the famous black-body distribution curve. But ...
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2answers
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Does the Sun have enough gravitation to bind its hydrogen/helium plasma?
"Does the Sun have enough gravitation to bind its hydrogen/helium plasma?"
So my question arises from the fact that high energy (or high temperature in other words) hydrogen or helium gas ...
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How long could the Sun power the Earth?
With the energy emitted by the sun in 1 second, how long could everyone household on earth be powered?
Currently we obviously can't harvest 100% of the sun's energy emissions.
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How does the Sun generate its energy?
We all know that the sun generates its energy from nuclear fusion in the core. The electromagnetic radiation produced slowly travels upwards, while constantly being absorbed and re-emitted by the ...
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How can I view through the water surface without reflection? [closed]
I am searching for a possibility to see the shallow grounds of water without reflections on the surface.
I am sailing in an area where there are reefs and shallow coral patches which can be dangerous ...
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1answer
62 views
If the Sun shrunk to the diameter of the earth, would Earth be habitable? [closed]
I was thinking about the sun. What if it shrunk in diameter to the size of the Earth? It wouldn't change the gravity much. But would it change the heat? If so, would the earth become uninhabitable?
My ...
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2answers
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Entropy of photons in the Sun / Earth system - Do infrared photons have higher entropy than ultraviolet/visible photons?
The entropy of a photon gas in equilibrium (emitting e.g., black-body radiation; BB) is
$S \propto V \cdot T^3$
where $V$ is the volume and $T$ is the temperature of the gas [see https://en.wikipedia....
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Why don't the nuclear fusion processes inside the sun produce electron antineutrinos $(\bar\nu_e)$?
Why don't the nuclear fusion processes inside the sun produce $\bar\nu_e$ despite having the same mass as $\nu_e$? Is the reason as simple as "there is no production channel for $\bar\nu_e$s.&...
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1answer
22 views
How are solar oscillations detected?
While reading through a page on beginner Helioseismology, I occasionally came across the terms p-modes or g-modes, which I know are caused by pressure and gravity.
I wanted to know how do satellites ...
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22 views
Books for Solar physics
I am thinking about applying for an internship at a university under a professor who does Helioseismology.
What resources would you recommend me for being ready for such an internship?
Can you suggest ...
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1answer
31 views
Positron-electron anihilation in the Sun
As 75% of the Sun is Hydrogen and 25% Helium and the latter derives from 4 hydrogen atoms where half of protons that formed neutrons expeled positive charges as positrons that anihilated with nearby ...
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2answers
85 views
What would happen to the Sun if you reflect all its emitted e.m. radiation back? [duplicate]
What would happen to the Sun if you would reflect, in whatever way, all the outgoing electromagnetic radiation (Solar winds can be neglected)?
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1answer
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Is it possible to make the Sun spin a coin in space?
Is it possible to do anything to a coin in space, so it begins to spin, using sunlight as the energy source?
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What is happening when magnetic field lines snap or break?
In discussions of sun spots and auroras on Earth, magnetic field lines are often described as "snapping" or "breaking", with the result of releasing charged particles very ...
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0answers
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Where did the Sun get its angular momentum? [duplicate]
The planets in the solar system all travel around the Sun in the same
orbital direction, which is also the direction in which the Sun itself
rotates about its axis. Therefore our Solar system has ...
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1answer
28 views
Magnetic islands formed after magnetic reconnection
I often read about magnetic islands forming as a result of magnetic reconnection?
To my understanding, those are irregularities of the magnetic field right? If not, could someone help me understand ...
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3answers
69 views
Is the yellow Sun light produced by photon scattering inside the Sun?
If the hydrogen emits four distinct light frequencies as a gas and on the Sun surface the gravity cannot alter hydrogen state as a gas does the yellow component of sunlight come from its interior?
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Mysterious - different speeds at different latitudes of the Sun
I recently read here (Hyperphysics page on Sun) since the Sun is a gaseous body and hence different latitudes can rotate at varying speeds. Naively, I was guessing that the poles would have faster ...
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1answer
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Is peak temperature equivalent in east and west facing buildings?
East-facing condos/apartments are considered more valuable than west-facing condos by some due to perceived superior light quality and lower peak temperature. My assumption is total solar heat gain ...
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1answer
37 views
Cumulative Sun's radiation pressure exerts on Earth's surface
I have some discrepancies in what is in "Optics" (E. Hecht) and what I calculated, but it's simply formula, so I'm confused. I used:
$$F = \frac{\pi R^2 S}{c}$$
to calculate cumulative force of ...
