Questions tagged [the-sun]

Questions regarding the closest star to Earth, at the centre of the Solar System.

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How to I calcuate observed position of the Sun and Moon using the SOFA C library?

There are a number of answers on here that skirt the topic, but no concrete answers. I currently have an implementation based on "Astronomical Algorithms by Jean Meeus" for stars, moon, and ...
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How far could be an object from the Sun and still be under the influence of its gravitational field?

I'm trying to see how far can our star reaches with its gravity. I'm asking if anyone could give info as to what's our star's limit or the furthest object found in our solar system.
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Difficulty in using the telescope as a projector

I have been trying, but completely failing, to copy the arrangement for viewing the sun mentioned on this website: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun....
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what degree in the sky does the sun change color?

I would like to know at what angle in the sky the sun changes from a white yellow to orange and red. I know that after sunset it's considered twilight until 18° beneath the horizon. So how many ...
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What would happen to the Sun's evolution if it collided with another yellow dwarf?

How would the Sun evolve if it collided with another G-type main sequence star, perhaps a more massive one like Alpha Cen A? Since its mass would then be above the Chandrasekhar limit, could it ...
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Is there any formulae to calculate whether the sun will depress 18 degrees or more below the horizon on a certain day / location?

I'm trying to code a piece of software which will calculate some times for me that would greatly help me in my day to day but none of my formulae work if the sun doesn't go at least 18 degrees below ...
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1answer
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Does the sky get darker faster during the winter?

When one lives away from the equator, say at around 37° latitude, does the sky get darker faster after the sun sets in the winter as compared to the summer? Why is this the case? I believe that if ...
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How does the Sun's gravity have so much force and pull on the solar system? How does it scale?

Watched this video: https://fb.watch/1U0vCFBr0L/ Ok, so the distances are huge. And the sizes are much different. But I wonder how then the sun keeps the planets etc. orbiting it. If we swap out all ...
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How much more life could the Sun acquire via star lifting?

It has been proposed before that we could use this technique to remove hydrogen from the Sun to lower it's rate of fusion and extend it's life, so it doesn't fry our planet. I am wondering how much ...
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How much mass would have to be added to the Sun to significantly alter any of its characteristics?

While this might at first sound like an XKCD What If? question, let's proceed with it because astronomical objects do occasionally merge. How much mass would have to be added to the Sun to ...
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Sundial terminology

My homeschoolers are studying the sun & time. We have set up a fence post to create a shadow and we are using it with experiments I found on the web to track the sun. What we cannot find is ...
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How bright is the Sun in S-band?

As far as I can tell when the Voyagers listen to Earth they have the Sun in the same beam. I never did calculate how bright a blackbody Sun would be because I have no idea if that's representative of ...
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Broadband spectrum of Sun

Broadband spectrum is one which is inclusive of all the observed wavelength ranges. In the case of the BB spectra of our Sun, there is a sharp (non-differentiable) kink in the curve in the UV-range (...
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Why does the Sun deviate from a typical blackbody spectrum in the S band?

This is sort of a follow-up to this question, and my answer to it. The graph I see here details the radio (and other frequencies) emission of the sun. What's most notable and interesting to me is the ...
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1answer
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Missing line in solar spectrum

Referring to this answer to What's the rationale behind the false colours in solar observation photographs? which includes the table from Wikipedia's Fraunhofer lines: In the Table of wavelengths ...
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How large will our Sun get during the red giant phase (ie which planets will it engulf) before the helium flash?

I have read that our Sun will increase in size to a red giant. But after it goes through the helium flash it will contract somewhat. Then after that grow again to be even larger before finally ...
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Does the sun's rising/setting angle change every few months?

When I lived in Darwin, Australia, I noticed that the Sun set in a slightly different direction to the West. In the evenings, I used to sit on a couch and watch TV. There was a huge window to my right ...
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What would a red giant Sun look like from Proxima b?

As of now, Proxima b is the only confirmed planet (or dwarf planet if it didn't clear its orbit - sorry, couldn't resist) around Proxima Centauri, the nearest-known star to the Sun about 4.2 ly away. ...
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How does the Helioseismic and Magnetic Imager (HMI) compute the Magnetic Activity Index (MAI)?

I am looking for a description about how this number called Magnetic Activity Index (MAI) is calculated. All I know is that the processing pipeline of the instrument HMI calculates it. But I would ...
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What point does Earth actually orbit?

If we consider the two largest masses in our solar system - the Sun and Jupiter, by themselves, they will orbit a common barycenter which is somewhere offset from the Sun's center in the direction of ...
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Can lightning occur in stars like the Sun?

In the Wikipedia article about lightining, the following explanation is given about the electrification process in clouds: The details of the charging process are still being studied by scientists, ...
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How to calculate geocentric transformation to heliocentric coordinates?

I have Sun data (lon+lat+distance) in geocentric coordinates: but I want to visualize in heliocentric way. How to calculate that?
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Does the Sun and Moon basically appear to “move on the sky” identically regardless of location and date?

For a long time, I've been trying to use Stellarium (simulation) and many visualizations and animations in order to get a good idea of how the Sun and Moon move across the sky, as seen by a human from ...
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1answer
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How do the sun's light rays come to the world?

How do they come to the world? One of my friends who is a flat earther told me about how the rays seem to gather at one point, which sort of proves that the sun is close to us and not very big, in his ...
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What instruments are used to measure the distance to the Sun?

In the 18th century, the distance to the Sun was measured using the transits of Venus. Nowadays, the timing of radar pulses is used to measure the distance of things in our solar system. What ...
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Kepler and the Sun position

When Kepler went to Tycho Brahe, he learned that Tycho Brahe was using the mean position of the sun to note down the position of Mars. Well, Kepler needed to convert these datas of Brahe to do his own ...
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Before the 1761 transit, what was our best estimate of the distance to the Sun?

In 1761, many expeditions were launched to determine the distance to the Sun using parallax during the transit of Venus. Prior to the 1761 transit, what was the best estimate for the Earth-Sun ...
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Problem regarding the absorption lines 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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Do we know if there are asteroids leading or following Earth in Earth's orbit around the Sun?

A search of the Internet is so clouded with discussions about the asteroid belt or asteroids orbiting the planet Earth that I couldn't see an answer to my question. Do we know if there are asteroids ...
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Parent stars of our Sun - Where are its remains?

This is in a way related to this question. Question is: Our star is third generation star, which is explained by existing Barium. That Barium was created by other stars. Now, those stars must have ...
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Does Sun have a reflection on Earth?

The new Google Maps1 presents an actual view of Earth, with the current position of Sun illuminating half part of Earth in real time. It is quite an exquisite view. My question is based on the ...
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What would happen when the speed of the Sun's spin changes?

Does the Sun's spin have effect on the orbit of the Earth?
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Is it possible to generate random numbers from images of the sun? [closed]

If this is off topic, please change it to world-building. Is it possible to make a low cost heliography telescope, which is not digital, and which can be used to generate an worldwide numerical ...
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Was the Geocentric Model correct at all?

It's easy to find resources stating that the heliocentric model is right and geocentric is wrong. But how wrong was it? Was it correct in any way? It was built on incorrect assumptions, but despite ...
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Why is the sunset at different times at the same longitude at equinox?

I happen to live in two places that are literally at the same longitude but several thousand kilometers apart from each other (~47°N and ~68°N). It's just a few days until equinox - and I assumed that ...
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3answers
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Can our Sun become a black hole

Does every star become a black hole? Is there any probability that our sun can become a black hole? If yes then is it on its way to become a black hole? what is the current state of sun as per the ...
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Where can I still find solar film?

I, like many others, am excited to see the eclipse. I want to view the eclipse through my telescope, however, I don't have any solar safety equipment for solar viewing and I cannot find any online ...
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Why were solar constant measurements before TSIS-1 all about 0.3% high?

Phys.org's Solar energy tracker powers down after 17 years says: "The big surprise with TSI was that the amount of irradiance it measured was 4.6 watts per square meter less than what was ...
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When did scientists discover that the Sun has a life cycle and that it is going to die?

I have been researching the history of scientific studies about the the Sun. However I have been unable to find out much information about how the scientific consensus started forming around stars' ...
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Does the Sun have a numerical designation in any star catalogues?

Given the existence of large star catalogues listing millions of astronomical objects with numerical designations (such as Tabby's Star, KIC 8462852) it occurred to me that one of them might contain ...
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586 views

Why is 3GHz the best frequency at which to measure the sun's microwave output?

I have read that 3GHz is the best frequency at which to measure the sun's microwave output, but that measurements are made at 2.8GHz for historical reasons, however I can find no explanation of why ...
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How to calculate emission measure from EVE data? [closed]

I am trying to analyse solar flare temperatures from EVE FITS files in PYTHON. All I have are the irradiance values for a range of wavelength at every 10 seconds. I have made clear Gaussian fits to ...
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How to retrieve from NASA Horizons site the needed data to plot analemmas for other planets?

I posted such a question in space.stackexchange ( https://space.stackexchange.com/questions/46077/which-are-the-correct-input-parameters-for-nasa-horizons-query-to-get-the-right?noredirect=1#...
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Precession and the location of the sun on the horizon at equinox

The sun lines up with this fountain, which is at the Salk Institute, during the equinoxes. Will precession eventually throw the alignment out of whack?
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If the sun is a second or third generation star, where is the neutron star? [duplicate]

It is widely believed that before the Sun was another star, more pristine in its composition (mostly Hydrogen and perhaps some Helium). And maybe before it was yet another. This blog explains this via ...
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Is it dark inside the Sun?

This might sound like a strange question, but something got me thinking about it recently. The opacity of plasma in stellar interiors can get quite high, making for shorter free-paths for photons. In ...
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Surface of the Sun, or Jupiter, etc [duplicate]

I keep hearing and reading statements that refer to the "surface of the Sun" (how hot the surface of the sun is) or the "surface of Jupiter" (when the Shoemaker comets hit Jupiter)....
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What does the Sun “look like” below 100 MHz?

Radio2space.com's The Radio Sun says: At very low frequencies (below 0.1 GHz) and therefore at very long wavelengths (> 3m) the solar disk appears much bigger and brighter in the center, and its ...
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Why can't we see Saturn's phases from earth?

In the Astronomy Picture of the Day from August 8, 2020 ("Crescent Saturn"), the caption states From Earth, Saturn never shows a crescent phase Why is this? We can observe phases on ...
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Why is our heliosphere an asymmetric croissant shape?

The big, recent astronomy news about our heliosphere's asymmetric croissant shape has me confused.... Some articles mention the influence on our solar system's outermost boundary of very hot cations, ...

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