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Questions tagged [the-sun]

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

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108 votes
1 answer
22k views

How can there be 1,000 stellar ancestors before our Sun?

I've heard from a few sources* recently that the Sun is a 1,000th generation star, meaning it had a thousand stars that came before it based on its heavy-element content. I understand that earlier ...
Benjam's user avatar
  • 1,199
31 votes
3 answers
18k views

How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it?

How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it? We know the Sun is orbiting the galactic center every 225 million years. But how far are we from the ...
jmarina's user avatar
  • 1,016
17 votes
6 answers
13k views

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 ...
happybuddha's user avatar
10 votes
2 answers
3k views

Is it possible that the Sun has a binary partner (the Nemesis Theory) that has eluded detection? [duplicate]

I just recently learned about the theory that our Sun has a small companion star with a 26 million year orbit. This theory came about when it was realized that mass extinction events happened ...
Curious Layman's user avatar
15 votes
4 answers
131k views

How long does a sunrise or sunset take?

From the time that the sun appears on the horizon, or meets it on its setting, to the time that it is fully visible, or no longer visible on its setting, how much time passes? Secondly, is there a ...
user11308's user avatar
  • 153
2 votes
2 answers
2k 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 ...
uhoh's user avatar
  • 30.8k
20 votes
2 answers
8k views

Is Sun a part of a binary system?

Does our Sun have a counterpart, i.e., is it a part of a binary-system? If so, how does the other star look like and where is it?
stp30's user avatar
  • 575
12 votes
3 answers
5k views

Is the barycenter of the solar system usually outside of the sun?

I came across this picture on wikipedia: Note: From a quick search I gathered that although there are slight differences between the limb of the sun and the accepted radius of the sun, these ...
eps's user avatar
  • 231
9 votes
1 answer
852 views

What is the origin of the dust near the sun?

note: Solar Probe+ is now officially Parker Solar Probe In How can the Parker Solar Probe survive passing within 4 million miles of the sun's surface? I asked about the Solar Probe Plus mission. ...
uhoh's user avatar
  • 30.8k
48 votes
5 answers
9k views

Where does the Solar System end?

The Sun is roughly 4 light-years away from the closest star system, the Alpha Centauri system. The planets in our Solar System, however, aren't even close to that far away from the Sun. Where does our ...
HDE 226868's user avatar
  • 36.6k
26 votes
2 answers
3k views

How often do stars pass within 1 light year of the Sun?

Interstellar exchange of massive objects is difficult across several light years. But as the stars orbit the galaxy the distances between them change. I don't find data for neighbor star distances ...
LocalFluff's user avatar
  • 11.4k
6 votes
1 answer
3k views

What is the orbital period of our sun around its barycenter?

In years, what is the time it takes our sun to orbit around our solar system's barycenter?
sunSis's user avatar
  • 77
5 votes
1 answer
1k views

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 ...
Amiga500's user avatar
  • 203
4 votes
3 answers
2k views

Inverse of the sunrise equation - finding locations with a given sunrise time on a given day

I'm working on a project for fun where I represent some sleep data geographically. For a given day, I have a date, a time for falling asleep that night, and a time for waking up the next day. The idea ...
xanxerus's user avatar
14 votes
3 answers
33k views

Will just a glimpse (less than a second) of sun during partial solar eclipse damage eyes?

This question arose when I thought that on Normal Days, at least I have observed bright sun while going outside, going to office, in park etc. for less than a second. It happens almost daily. Not ...
Vikas's user avatar
  • 341
11 votes
5 answers
4k views

Does the Sun turn around a big star?

The Moon orbits the Earth. The Earth orbits the Sun. Does the Sun orbit another bigger star? If so, does this star orbit, in turn, a very big star? ... etc ... What are all the intermediate ...
Sebastien Palcoux's user avatar
10 votes
1 answer
5k views

What are the chances of a star colliding with another during a galactic collision?

My specific example for the question is the future collision of the galaxies Milky Way (our own galaxy) and Andromeda in a couple billion years. The star in question is obviously the sun in this case. ...
HotSaucey's user avatar
  • 1,073
7 votes
1 answer
4k views

Are there accurate equinox and solstice predictions for the distant past?

I am trying to find information on the equinox/solstice dates before 1600, more exactly referring up to 10,000 BCE so as to create a sort of calculator on an Excel spreadsheet. I have read about the ...
SC for reinstatement of Monica's user avatar
6 votes
1 answer
1k 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 ...
uhoh's user avatar
  • 30.8k
4 votes
1 answer
184 views

What can be learned from low frequency radio astronomy available outside of Earth's ionosphere?

As discussions and answers to How large does refraction become in radioastronomy? point out, it is difficult to do radio astronomy much below 30 MHz (or 10 MHz depending on how aggressive you are in ...
uhoh's user avatar
  • 30.8k
26 votes
2 answers
3k views

Is it a coincidence that both the Sun and the Moon look of same size from the Earth?

The Sun is huge, when compared to the Moon. Despite the huge difference in their size and distance from Earth, is it purely coincidental that they both look almost the same from Earth?
Raj's user avatar
  • 371
10 votes
1 answer
1k views

Best approximation for Sun's trajectory around galactic center?

What is the current best approximation for the path the Sun takes around the center of the Milky Way? I have found some information on the approximate position of the Milky Way's center, the speed of ...
tschie's user avatar
  • 103
8 votes
1 answer
2k views

Effect of the obliquity of the ecliptic / tilt of the Earth on the equation of time

In attempting to answer the question “why aren’t changes in sunset and sunrise times symmetrical around the solstices ?” I’ve got stuck on being able to explain the effect of the obliquity of the ...
Mike Warren's user avatar
4 votes
1 answer
959 views

Is the Sun slightly blue in the center? - Wavelength-dependent limb darkening of the Sun

I've slightly modified the title to try to attract some attention. If we call sunlight "white" and limb darkening is a result of seeing deeper at normal incidence and shallower at oblique incidence, ...
uhoh's user avatar
  • 30.8k
37 votes
3 answers
10k views

What happens to the 99.9 % of the sun-rays that do not fall on any planets or any other celestial body?

I assume that about 99.9% of the sun-rays that do not fall on any planet or any other celestial body keep on traveling farther and farther unto infinity. Apparently such rays get lost. Keeping in mind ...
S C Sawhney's user avatar
29 votes
3 answers
5k views

What is this web on the surface of the Sun?

I was going through my Social Media Feed and found the attached post too frequent. The caption reads this is the best image of our Sun. Just as an example, the Universe Today's This is the Highest ...
Pranay's user avatar
  • 783
16 votes
2 answers
3k views

What does the Sun's orbit within the Solar System look like?

Everything in the Solar System revolves around the "barycenter": the overall center of mass. This barycenter is not in the center of the Sun. Some articles and essays I've read go so far as to suggest ...
Ricky's user avatar
  • 1,345
13 votes
6 answers
27k views

Why doesn't the sun pull the moon away from earth?

If the suns gravitational pull is strong enough to hold much larger masses in place (all the planets) and at much greater distances (all planets further away from the sun then earth) why does it not ...
TheDudeAbides's user avatar
9 votes
5 answers
11k views

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 ...
Anthony X's user avatar
  • 793
9 votes
1 answer
4k views

Are planets moving away from the sun?

I saw on the tv show Through the Wormhole (hosted by Morgan Freeman) that the planets in our solar system have been continuously moving away from the sun for millions of years. however, when I try to ...
Yvonne Liew's user avatar
8 votes
6 answers
38k views

When we see the Sun, do we actually see its past?

The Sun's rays hit our eyes around 8 minutes after they are emitted from the Sun. Does this mean that the Sun that we see is always the Sun as it was some 8 minutes before? I strongly think this must ...
Deepeshkumar's user avatar
6 votes
3 answers
2k views

Local mean time & Solar Noon

Is local mean time supposed to represent actual sun movement? Does 12pm on local mean time (not clock time), mean that the sun is on meridian or solar noon? I understand LMT means 1 degree for 4 ...
emotionallyattached's user avatar
4 votes
1 answer
729 views

How much of the sun needs to be blocked in order to see a noticeable drop in brightness

I live in NYC and just experienced the eclipse. What fascinated me the most was that despite the fact that the sun was about 70% blocked, the area was not noticeably dimmer. If the news wasn't saying ...
David says Reinstate Monica's user avatar
4 votes
2 answers
320 views

Sunset on [Mountain] from [Viewing Point]

How do I get the days in this year when the sun will set exactly on top of Fuji as viewed from Enoshima. I shamefully admit that I just want to take a nice picture of Fuji.
Caesar's user avatar
  • 193
56 votes
2 answers
11k views

Sun constantly converts mass into energy, will this cause its gravity to decrease?

If the sun is constantly converting the mass into energy, then will its gravitational field continue decreasing?
Mohan Mone's user avatar
46 votes
2 answers
6k views

Does the sun cross other spiral arms in its movement around the galaxy's center?

Today, Ansa.it released an article that states: [...]. In questo suo peregrinare galattico, il Sole ha attraversato anche i due bracci della Via Lattea Perseo e Centauro. "Sono zone di alta ...
Patrick Trentin's user avatar
19 votes
2 answers
1k views

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 ...
User3141's user avatar
  • 319
18 votes
6 answers
13k views

Moon's orbit around the Sun

The Earth revolves around the Sun and the Moon revolves around the Earth. Out of curiosity I started thinking about the orbit of the Moon around the Sun and expected (assumed) it to be as follows: ...
Umang Chaudhari's user avatar
17 votes
3 answers
8k views

In which direction is the sun travelling?

Relative to this simple drawing, can someone explain to me, in which direction is the sun and its solar system travelling, which star (irrespective of distance) is closest to that direction, and in ...
Alonda's user avatar
  • 293
11 votes
4 answers
10k views

Why is twilight longer in summer than winter and shortest at the equinox

I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with ...
firebush's user avatar
  • 231
9 votes
2 answers
2k views

What is the exact reason for the Sun's differential rotation to occur?

The following is an excerpt from the Wikipedia article for "Differential Rotation": Differential rotation is seen when different parts of a rotating object move with different angular ...
user avatar
6 votes
1 answer
602 views

What are the experimental limits to the residual charge of the Sun?

The question Can a Neutron Star become charged? and the associated comments and answers started me wondering; Are there measurements of, or experimental limits to the residual charge of the Sun? ...
uhoh's user avatar
  • 30.8k
5 votes
2 answers
2k views

Photosphere is relatively transparent. Is that right?

This book, Astronomy in Minutes: 200 Key Concepts Explained in an Instant, by Giles Sparrow, says the photosphere is a visible surface at first, but after that, it says the Sun becomes cool and then ...
Purple Rain Kim's user avatar
5 votes
1 answer
426 views

When are the planets occulted by the sun?

There are numerous lists available of past and future planetary transits and occultations, but I can't find any that list transits behind the sun. Do the planets in our solar system ever pass ...
Robert's user avatar
  • 955
4 votes
2 answers
912 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 ...
Skyblade's user avatar
  • 143
2 votes
3 answers
2k views

Calculate position of the Sun in ECEF

I'm making a very basic orbit simulator in C# using the Helix Toolkit. I want to position the Helix lighting object at the sun, but also be able to calculate solar eclipse by the moon and earth for a ...
a_here_and_now's user avatar
1 vote
1 answer
2k views

Calculate how long it takes for the sun to complete one orbit around the galaxy?

We know the speed that the sun travels around the galaxy is $220\, {\rm km/s} = 0.00021 \, {\rm parsec/year}$. I'm unsure of how to find the period?
user32018's user avatar
59 votes
2 answers
15k 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 ...
Murg's user avatar
  • 939
57 votes
4 answers
17k views

How did Astronomers deduce that the Sun was not a ball of fire?

Its common knowledge that people used to think that the sun is a ball of fire or molten metal, but when did science start to prove otherwise?
Krish's user avatar
  • 703
46 votes
1 answer
6k views

Why does the Sun have different day lengths, but not the gas giants?

The Sun's rotation period varies from about 25 days at the equator to about 38 days at the poles. As I understand it, this is because the Sun is not solid, and because of the way centripetal force ...
Allure's user avatar
  • 4,544

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