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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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129
votes
2answers
20k views

How much gold is there in our sun?

XKCD 1944 claims that there is "more gold in the sun than water in the oceans". Is this really true?
120
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3answers
15k views

How loud would the Sun be?

Sound can't travel through outer space. But if it could, how loud would the Sun be? Would the sound be dangerous to life on Earth, or would we barely hear it from this distance?
82
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6answers
6k views

Does the Sun rotate?

The planets rotate as an after effect of their creation, the dust clouds that compressed span as they did so and the inertia has kept it rotating ever since. It's fairly easy to prove that planetary ...
72
votes
1answer
11k 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 ...
55
votes
5answers
10k views

When will the Sun end all human life on Earth?

If nothing else wipes out human existence prior to this, at what point will the Sun make Earth uninhabitable for humans?
55
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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 ...
51
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5answers
11k views

Why is moon light not the same color as sunlight?

The light from the moon is light being reflected from the sun. The sun, in space, is white. But on Earth, when the light is filtered through an atmosphere, the light appears yellow. So then, why is ...
44
votes
2answers
4k 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 ...
39
votes
1answer
5k 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 ...
38
votes
4answers
6k 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 ...
33
votes
3answers
9k 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 ...
32
votes
2answers
11k 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 ...
31
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6answers
10k views

Why is the Sun's density less than the inner planets?

The density of the Sun is $1410~\frac{\text{kg}}{\text{m}^{3}}$ and Mercury's is $5430~\frac{\text{kg}}{\text{m}^{3}}$, but shouldn't the Sun be denser? Because when the Solar System was forming, ...
29
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4answers
8k views

Why there is no smoke around the Sun?

Where there is fire, there is always smoke. So why there isn't any smoke near the Sun?
27
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3answers
6k views

Where did the Sun get hydrogen to work with if it is in the 3rd generation of stars?

As I see here, the Sun belongs to the Population I group of stars, which is the 3rd generation of the stars in our universe. 1st generation stars are Population III, 2nd generation are Population II, ...
26
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2answers
20k views

Why do sunspots appear dark?

Sunspots, such as this one, appear dark: Why?
25
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9answers
11k views

Simple experimental evidence that Earth revolves around Sun

What are the simplest experiments or calculations that give evidence that the earth revolves around the sun? Can you please explain them and reference the history? Many simple explanations such as ...
25
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3answers
7k views

Does the Sun have permanent geographical features?

Equivalent formulations of this question: Would it make any sense to draw a map of the Sun? Is the Sun heterogeneous with respect to latitude and longitude? (I know that it is heterogeneous with ...
25
votes
1answer
843 views

Why is the Sun's atmosphere (the corona) so hot?

The visible surface of the Sun is 6000 degrees Celsius but the gas in the solar corona is at least 1 million degrees. What heats the solar corona?
24
votes
3answers
1k views

Is it odd that our Sun has so many planets?

The internet is abuzz with the new evidence of the possible ninth planet in our Solar System. With those nine objects, the asteroid belt, the Kuiper belt, and everything else in our Solar System - the ...
24
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2answers
11k 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 ...
22
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2answers
8k views

Is our sun in a star cluster?

Sorry for the absolute begginer question here, but is our sun a part of some globular cluster? It is something related to Virgo supercluster?
22
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4answers
30k views

Does the Sun belong to a constellation?

Each new star we find is generally considered to be part of the constellation it is nearest to. Our Sun is obviously a star, just much closer. Is our Sun part of any constellation? If so, which ...
22
votes
1answer
3k views

What's the brightness of Alpha Centauri from Proxima Centauri?

Self-explanatory, but I would like a comparison as well. Is the light enough to see by? How disrupted will the pitch darkness on the spot opposite of the 'solar pole' be?
21
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2answers
2k views

At what distance from Earth would our Sun be the same apparent magnitude as the next brightest star in the sky?

When I stand outside looking at the night sky, to my untrained eye, everything except the moon looks like a star. I know intellectually that some are planets circling our sun, and some are entire ...
21
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2answers
15k 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?
21
votes
1answer
553 views

How stable are Lissajous orbits?

Now that the Gaia Space Telescope is on it's way to the Sun-Earth L2 Lagrangian point (SEL2), I start wondering about the stability of Gaia's orbit there. The Planck Telescope is already there, as was ...
20
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4answers
2k views

Is it a coincidence that both the sun and moon look of same size from earth?

The sun is huge when compared to 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?
20
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2answers
3k views

How bright would the sun appear from the hypothetical Planet Nine proposed by Caltech?

Theoretical Planet Nine, proposed by Caltech's Mike Brown and Konstantin Batygin, is said to have a 15-20 thousand year orbit. Approximately how bright would the sun appear from Planet Nine aphelion ...
20
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5answers
21k views

What would the effects be on Earth if Jupiter was turned into a star?

In Clarke's book 2010, the monolith and its brethren turned Jupiter into the small star nicknamed Lucifer. Ignoring the reality that we won't have any magical ...
20
votes
1answer
292 views

How often do comets survive passage by the Sun?

I had heard that comet ISON might not survive a close pass by our Sun, and I was curious about the odds of how other comets had fared. So, how often do other comets survive a close pass by our sun? ...
19
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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 ...
19
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4answers
4k views

Did the earth form outside the solar system?

Why isn't it possible that the earth formed outside the solar system and got attracted later by the Sun? I just need arguments to defeat this hypothesis.
19
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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 ...
19
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1answer
4k views

How far do we have to go to leave the galaxy?

How far is the sun from the edge of the galaxy in the following directions? Moving along the shortest path parallel to the galactic plane (outward radially) Moving along the longest path parallel to ...
19
votes
2answers
2k views

Do other planets in our solar system experience eclipses or is this unique to Earth?

Here on Earth we get to experience lunar and solar eclipses. Is this pure coincidence that everything happens to line up? Do other planets in the solar system experience this phenomenon or is this ...
18
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?
18
votes
1answer
11k views

How many sun-like stars are there in the universe?

After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets ...
17
votes
7answers
9k views

Why doesn't Earth's axis change during the year?

My understanding is that the Earth's axis points in the same direction in space during its entire orbit around the sun. And this is what causes our seasons. My question is why doesn't the axis follow ...
17
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4answers
11k views

How was the core temperature of the Sun estimated?

It was estimated that the heat inside the core of the Sun inside around 15 000 000 °C - this value is extremely enormous. How did scientists estimate this value?
16
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2answers
20k views

Will Earth lose the Moon before the Sun goes into supernova?

Ive read on some sites and saw on youtube videos that the moon is getting away from earth by 1-3 cm a year. Is this enough to make the Earth lose the Moon before the Sun goes into Supernova? Im ...
16
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3answers
3k 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
1answer
379 views

Have we ever observed a body, such as a large asteroid, “hitting” the Sun?

Some other SE questions about launching ICBM's into the sun got me wondering whether we have ever observed an object on a path that intersected with the Sun? How close did it get?
16
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3answers
1k views

Which stars did the Sun form with?

The Sun formed 4.5 billion years ago, in a molecular cloud. I assume that there were other stars in the vicinity (as is common in molecular clouds). Which stars are they? Where are they now? Are they ...
15
votes
4answers
44k views

Can this picture of the moon directly above the sun from the horizon be real?

I recently saw this image, but somebody told me that it is fake, possibly photoshopped. The moon and the sun appear to be on the same perpendicular from the horizon. Is there any way to tell if this ...
15
votes
6answers
4k views

Are we still going to have rainbows if Sun is replaced by another star?

Rainbow is a property of light splitting due to the water molecule present in the clouds and is related to the light emitted by our Sun. Our sun is a yellow star. Now if we replace sun by a blue giant ...
15
votes
4answers
64k 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 ...
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 ...
15
votes
3answers
302 views

What is the Neupert Effect?

This effect is frequently discussed in the context of solar time series. In particular, it a relationship between soft x-ray (thermal emission) and hard x-ray (nonthermal emission) from the Sun.
15
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3answers
670 views

Is the rotation of the Sun and the rotation/orbit of the Moon around the Earth a coincidence?

While looking at sunspot information in connection with Amateur Radio, I found that the Sun rotates on a period from 27 days to 31 days. Its rotation is differential, at the equator it spins at a ...