Questions tagged [the-sun]

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

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85
votes
1answer
15k 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 ...
9
votes
2answers
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 ...
26
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2answers
13k 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 ...
19
votes
2answers
7k 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?
15
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4answers
97k 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 ...
3
votes
3answers
1k 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 ...
8
votes
1answer
626 views

What is the origin of the dust near the sun?

note: Solar Probe+ is now officially Parker Solar Probe In https://space.stackexchange.com/q/17498/12102 I asked about the Solar Probe Plus mission. Reading a 2008 report I saw that there is an ...
44
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5answers
7k views

Where does the Solar System end?

This is a question I've heard many times in the past, and a quick search of the site says it hasn't been asked here, so I figured I might as well ask (and answer) it. I know that it is rare for ...
9
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5answers
2k 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 ...
8
votes
1answer
2k 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 ...
5
votes
1answer
833 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 ...
0
votes
2answers
557 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 ...
22
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2answers
2k 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?
21
votes
2answers
2k views

How often do stars pass close (~1ly) to 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 ...
3
votes
1answer
1k 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?
13
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1answer
2k 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 ...
8
votes
1answer
3k 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. ...
10
votes
1answer
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 ...
4
votes
2answers
618 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 ...
4
votes
1answer
606 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, ...
11
votes
6answers
20k 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 ...
30
votes
3answers
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 ...
9
votes
1answer
3k 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 ...
7
votes
4answers
8k 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 ...
6
votes
3answers
24k 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 ...
7
votes
1answer
1k views

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

In an 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 ...
4
votes
1answer
139 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 ...
4
votes
2answers
219 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.
33
votes
3answers
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 ...
16
votes
3answers
5k 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 ...
16
votes
8answers
7k 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: ...
12
votes
3answers
7k 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 ...
4
votes
1answer
374 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 ...
13
votes
3answers
5k views

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

This doubt 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 ...
2
votes
3answers
1k 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 ...
57
votes
2answers
13k 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 ...
32
votes
3answers
12k views

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 ...
52
votes
2answers
10k 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?
44
votes
2answers
5k 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 ...
25
votes
2answers
20k views

Why is it okay to watch a sunset but not an eclipse?

People watch sunsets all the time. You don't see people using special "sunset glasses". Yet with an eclipse, warnings are posted everywhere not to view it without special glasses. Why is this?
28
votes
2answers
23k views

Why do sunspots appear dark?

Sunspots, such as this one, appear dark: Why?
15
votes
3answers
3k views

How old is our Sun in Galactic years?

A year is measured as the amount of time it takes Earth to orbit the Sun once, a Galactic year is the time it takes our sun to make one full orbit of the center of the Galaxy. In Galactic years, how ...
9
votes
1answer
1k views

How does the earth's plane of orbit (ecliptic) vary over time?

Does the earth's orbital plane change with time relative to the distant stars? Does the Sun follow the same path through the zodiac (ignoring proper motions of the zodiacal stars)?
15
votes
5answers
6k 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 ...
13
votes
2answers
3k views

How much mass will the Sun have when it becomes a white dwarf?

In 4 billion years, when our Sun sheds all of its outer gas layers and turns into a white dwarf, how much mass will the white dwarf have compared to what the sun has today? Will the planets still ...
7
votes
1answer
5k views

What is the angle between the equator of the sun, and the plane of the Earth's orbit

I want to know the angle between the plane that passes through the centre of sun and is perpendicular to its spin axis, and the plane that contains the orbit of earth around sun? Is this a fixed ...
6
votes
4answers
2k views

Are we sure solar cycle is not related to the orbit of Jupiter?

Are we still debating the relationship between Jupiter and solar cycle? If not, what is the common or mainstream opinion about this topic? Or in other words, have we disproved the solar cycle is ...
4
votes
1answer
156 views

Why didn't we see those campfires on the Sun until now?

What is it about its optics and instrumentation (aperture, sensors, filters), being in space and distance from the Sun on 30 May 2020 that allowed Solar Orbiter's HRIEUV telescope to see something ...
2
votes
1answer
179 views

What is the dielectric constant of a star?

What is the dielectric constant of a star, especially its corona? Is it of order 1 or is it quite large? How much do "impurities" (elements other than H and He) affect the dielectric ...
11
votes
3answers
4k views

How can the Sun burn without oxygen?

How does the Sun burn without oxygen? It might not be burning but a big part of the society speaks of it as burning. So how does it work?