Questions tagged [the-sun]
Questions regarding the closest star to Earth, at the centre of the Solar System.
546
questions
2
votes
1answer
46 views
How much does the stellar radius change if seen through different filters?
I know that the radius of a star should be different depending on the filter being used to do the observation. That is, the bluer the filter, the smaller the measured stellar radius. I know this ...
-2
votes
1answer
89 views
Solar degrees vs Calendar days [closed]
What is the difference between solar degrees and Calendar days. Is there any formula to convert one to another.
for example Starting from 1/1/2000
1/1/2000 + 300 calendar days=some date (easy)
1/...
5
votes
2answers
349 views
Why does the Solar Wind consist of charged particles?
The Wikipedia article on Solar Wind gives the following explanation:
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma ...
4
votes
0answers
39 views
Simulate earth, moon, sun constellation with dates
I would like to simulate the three object distance, specifically the distance of the moon to both, sun and earth for further investigation into tide prediction.
What would be a good starting point ...
6
votes
1answer
141 views
A vertical stick's shadow at solar noon should be straight north/south, right?
At true solar noon, the subsolar point should be directly north or south of you, and therefore a vertical stick's shadow should point directly north or south, right?
The Wikipedia page for Sun Path ...
1
vote
1answer
128 views
What would we notice if the Sun stopped fusing atoms? [duplicate]
(This question was stimulated by Would we have more than 8 minutes of light, if the sun "went out"?)
According to this answer, the "Sun has enough gravitational potential energy to supply ...
54
votes
2answers
12k views
Would we have more than 8 minutes of light, if the sun “went out”?
The common theory is, that if the Sun "shut down", we would see the light for eight more minutes (the time that it takes the photons to reach the Earth).
However recently I have read that photons ...
0
votes
0answers
41 views
IAO 2015 Question 1 Noon at the Olympiad
Yesterday, on October 16, 2015, the upper culmination of the Sun at the venue of the Olympiad was at 11:29:44 local time. Calculate as accurate as possible at what time the upper culmination of the ...
18
votes
4answers
8k views
Would an object shot from earth fall into the sun?
Would an object shot from earth fall into the sun?
If an object is shot at 107,000 km/h via rocket or otherwise, in the opposite direction to our orbit about the sun, it will be traveling at 0 km/h ...
5
votes
1answer
344 views
Is the resulting light from a supernova a product of photons bouncing around in the Sun?
I was thinking about how photons formed in the centre of the Sun take quite a long time to exit the surface. And it occurred to me that at the end of a star's life (during a supernova, given that it's ...
3
votes
0answers
58 views
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 ...
5
votes
1answer
57 views
What is the intensity distribution of visible light over the solar disk?
What is the distribution of the visible spectrum over the solar disk?
Images of the Sun using the visible spectrum suggest that the light emmitted from the edge is almost equal to the light emmited ...
1
vote
0answers
25 views
Angle of the Sun during winter solstice
What is the angle of the Sun on the eastern horizon at 35° latitude if it is the winter solstice?
1
vote
2answers
59 views
What parameters cause sunburn? [closed]
I am new to this site so if the question doesn't fit in this forum feel free to remove it.
I have read here https://en.wikipedia.org/wiki/Sunburn of all the causes of sunburn and I was mostly aware ...
3
votes
1answer
105 views
Any simple experiment with an H-alpha telescope?
Is there any simple experiment that can be done with an H-alpha telescope, for example to estimate the Sun's mass, size, distance, temperature or intensity?
I give lessons about renewable energy and ...
1
vote
0answers
51 views
Is there any possibility that a gas planet turns into a star [duplicate]
Since the sun is made of one of elements hydrogen
Why Saturn and jupiter doesnt turn into a star since they have a elements of hydrogen ?
1
vote
0answers
111 views
How big a rock can hit the sun and it not matter? [duplicate]
If a rock the size of Oumuamua were to crash into the sun — assume central collision — would it materially affect the sun’s behaviour? Would unaided humans (rather than sun-tastic special telescopes) ...
1
vote
2answers
104 views
Does the magnetic field of earth restore?
The magnetic field of earth protects us from solar wind as we know it, but after the solar wind interacts our magnetic field.
Does the magnetic field of earth restore after it deflects the solar ...
1
vote
1answer
40 views
Maxwell stress contribution to $\nabla \cdot \mathbf{P}$ in the Navier-Stokes equation for fluid in stars
I was reading through the following extract outlining how the Maxwell stress contributes to the $\nabla \cdot \mathbf{P}$ term of the Navier-Stokes equation for fluids in a star. Here $\mathbf{P}$ is ...
0
votes
1answer
105 views
Why is the Sun's Luminosity not equal to the Zero Point Luminosity?
I was doing some research and found that the zero-point luminosity was $L_\odot = 3.75\times 10^{28} $, while the sun's reported luminosity was $L_{Sun} = 3.828\times 10^{26}$, according to Wikipedia. ...
3
votes
1answer
136 views
Why is our Sun hotter than UY Scuti?
As Wikipedia says the surface temperature of UY Scuti is 3,365 K and the sun is 5,778 K
Why is the Sun hotter than a supergiant star like UY Scuti?
3
votes
2answers
182 views
Can an Earth-like planet survive if our Sun went Supernova?
First, I would like to point out, yes, our sun does not have enough mass to be a candidate for Supernova, this is a scenario were our sun is though, and after the various life cycle stages of the sun ...
3
votes
1answer
108 views
At what depth below the Sun's surface does the density reach that of water?
I'd like to write a short supplementary answer to A probe floating in Sun's surface but in order to do so I need to know at roughly what depth relative to the Sun's surface the mass density reaches 1 ...
0
votes
2answers
66 views
What is the density profile within the Sun's photosphere? Which one of these is wrong?
The Sun's photosphere contains the Sun's surface as defined by opacity = 2/3 point. I'd like to see the profile of mass density from bottom to top of the photosphere. I did a quick search and got ...
1
vote
1answer
39 views
Earth's perihelion vs winter solstice [duplicate]
I found that Earth's perihelion occurs roughly two weeks after winter solstice similar thing happens for summer solstice and aphelion. I understand what those terms mean but I don't understand the ...
3
votes
2answers
333 views
What would happen if a Sun-like star were to consume a Jupiter-like planet?
A substantial number of discovered exoplanet systems are likely contain more than one gas giant with distances far closer to the star than in our solar system.
It is known that in solar system ...
1
vote
2answers
71 views
What are some examples of routine human activity times for certain cultures/peopes that are based on the position of the sun?
What are some examples of timekeeping that are based on the height/angle/position of the sun. Two examples that come to mind are the times of the Islamic prayers times and the golden hour in ...
2
votes
1answer
50 views
How could the polarizer in early coronagraphs make the Sun's corona more visible against the daytime sky?
Wikipedia's Coronagraph; Invention says:
High Altitude Observatory's Mark IV Coronagraph on top of Mauna Loa, uses polarization to distinguish sky brightness from the image of the corona: both ...
2
votes
1answer
33 views
Where can I find a good solar irradiance chart for the infrared?
I'm trying to understand the results of the ExoMars Trace Gas Orbiter vs the Mars Express in terms of their abilities to find methane on the surface of Mars. The solution that I'm coming to is that it ...
1
vote
1answer
118 views
What keeps the planets of the solar system moving in their fixed orbits?
Models of the solar system show each planet moving around on its own orbit.
Is is really because of the Sun that every planets remains in its own fixed orbit?
0
votes
1answer
89 views
The sun's SOLAR WIND VS MAGNETAR
As we know magnetars have strong magnetic field but what if we swap earth with a magnetar and the sun will released a solar wind. Is the magnetar affected by the solar wind or not ?
4
votes
1answer
115 views
Is the longitude assigned to sunspots spherical or projected?
Sunspot maps are created from a projection of the sun, so the coordinates of sunspots (or active regions in general) are assigned according to it.
Do these coordinates correspond to actual spherical ...
2
votes
4answers
215 views
If fusion only happens near the center of the sun, what's with all the “fire” on the surface?
I understand that it isn't "fire" in the combustion of oxygen sense, but I can't find an answer online about what we're witnessing happening at the visible surface of the sun if all actual fusion ...
0
votes
1answer
128 views
Does the sun have a vertical movment?
As the Sun moves along with the planets does the sun exhibit vertical movement? That is, does it traverse in different planes?
0
votes
0answers
26 views
what/how do we mean/derive statistical equilibrium equation of certain energy levels?
While reading the research paper "Excitation of the Fe XIII Spectrum in the Solar Corona" by D.R. Flower and G. Pineau des Forets in the summary I found the concept of statistical equilibrium equation ...
2
votes
0answers
83 views
Orbital decay of the Earth's orbit and Earth's moving closer to the Sun
If we consider orbital decay of the Earth's orbit, then can we counter argue with the following reasons?
Due to tidal effects transferring small amounts of angular momentum from the Sun's spin to ...
2
votes
1answer
57 views
Why doesn't the solar azimuth vary uniformly
For the past few dates, I've been observing the rotation of the earth around the sun and noticed that the azimuth of the sun doesn't vary uniformly throughout the day. The azimuth varies faster during ...
1
vote
2answers
293 views
How to calculate solar coordinates. (Right Ascension, Declination, and ultimately the Altitude and Azimuth of the Sun)
As the title says I am trying to calculate solar coordinates of the sun for a given location and time. I have spent many 10's of hours on this without success so I will sincerely appreciate help on ...
1
vote
1answer
81 views
Date of solstices pre-0 AD
I’ve written a script based on Meeus’s Astronomical Algorithms to calculate the position of the sun, moon etc. up to about 4000 BC.
Everything looks good, except when I go to 4000 BC the solstice are ...
1
vote
2answers
227 views
Does the sun have cycles causing temperature changes on Earth?
Can the Sun go through seasons or cycles to cause a temperature change?
Could the Sun have to go through any kind of thermal cycle to change the climate on Earth and by how much?
2
votes
3answers
184 views
How moon is visible during sun is still shining, simple explanation please! [duplicate]
Sometimes I observed there is moon on sky at noon and sun is also shining.
How is this possible?
I also observed dull moon is still on sky at 7:00 AM to 8:00 AM while sun is rising. My local time is ...
1
vote
3answers
228 views
Why is the equinoxes only 2 days and not more?
The earth is tilted at 23.5 degrees which means that in the solstices the north/south hemisphere is more radiated by the sun and the tilt to the sun is maximum.
In the equinoxes, the tilt is not ...
1
vote
1answer
131 views
How long would an occultation by a TNO last?
A trans-Neptunian object, 1 million km from the observer, with an angular diameter of 0.126° occults the Sun (angular diameter of 0.004°) and the TNO and the observer are moving in the same direction, ...
0
votes
1answer
44 views
Seasonal effect based on Earth position [duplicate]
I know that Earth rotates around the Sun in an oval route:
And I know the seasons happen, because the axis of the Earth is not vertical. I think it is 23 degree slope.
How come the distance from the ...
3
votes
4answers
175 views
Is the equinox Sun always at the same zodiac sign in the ecliptic belt?
During the year the Sun moves along the ecliptic passing all the signs of the zodiac belt, in my understanding. This means that it takes ~1 month to go from one zodiac sign to the next.
The ...
1
vote
2answers
82 views
Should the sun appear very low in the horizon if its path is always between the two tropics?
If the sun never rises above the tropic of cancer and never goes bellow (southern) of the tropic of capricorn then it seems that it should appear to the observer lower and lower in the horizon for as ...
1
vote
1answer
100 views
South of the tropics, where does the sun's noon shadow point?
If I understand correctly, in countries to the north of the tropics the sun's noon shadow points north.
What happens south of the tropics? Is it pointing south?
2
votes
1answer
66 views
What does the Sun look like from the heliopause?
I calculated the angular diameter of the Sun at the heliopause to be 0.004°. If that is correct, would the Sun appear as a disk, or like the pinpoint of light from a star?
How bright would the ...
0
votes
1answer
162 views
Could the Sun have liquid iron in orbit?
How close of an orbit to the Sun could an iron meteor get before it melts into a ball?
1
vote
0answers
40 views
Angle between earth's angular momentum and earth's axis
I think this picture is correct because for earth astronomical day is slightly shorter than solar day. (Is it a rule of thumb for planets? Where can I read such data?)
Source
So the angle between ...
