Questions tagged [the-sun]

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

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1answer
79 views

Can the sun explode in fact? [duplicate]

Because of fusion inside the sun, it pushes it apart, why sun doesn't explode then? The pressure inside should make it explode right?
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3answers
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Can you see the shadow of a spaceship on the Moon while looking towards the Earth?

It's a classic movie cliche. We see the surface of the Moon with the Earth in the distance and a dark shadow of an invading alien spaceship slowly covering the landscape. We see this in the opening ...
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Ecliptic and it's poles

Well, I have this picture and a couple of tasks to it: It is the Sun's path, a.k.a. ecliptic in autumn, 22-23 of September or on the day when autumnal equinox happens. I am to answer these questions: ...
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1answer
49 views

At what time of the day of autumnal equinox the Sun's equatorial coordinates reach max value?

I'm trying to solve this task: At what point in time of autumnal equinox day, at sunrise or sunset will a) the declination of the Sun b) the right ascension of the Sun reach the maximum value? I'm ...
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1answer
127 views

Role of aerobraking in cometary orbits?

I'm doing some research about comet perturbations, and have noticed that the outbound aphelion is often different from the inbound aphelion, particularly due to the gravitational influence of the ...
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1answer
78 views

What is the relationship between the shape of the analemma and the sun's azimuth at sunset at a given latitude?

I want to know how the sun's azimuth at sunset changes over the course of a year. At first, I thought it would have purely sinusoidal motion, hitting its maxima and minima at the solstices, and ...
4
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1answer
70 views

How much mass is lost in the red giant phase of a sun?

The red giant phase of suns may go relatively quick. How will this impact suns' total mass. Are there massive mass losses taking place when this happen? If so, do we know how much? The sizes of red ...
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1answer
55 views

Sun expansion's effect on planets

When the Sun gets to the age at which it will rapidly expand what effect would it have to the outer planets and it's moons? Would it make new habitable areas of the solar system?
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0answers
80 views

Help finding a database or analysis of plage regions on the Sun

Plages are phenomena of stellar activity. A plage is a bright region in the chromosphere of the Sun, typically found in and around active regions. The term itself is poetically taken from the French ...
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1answer
73 views

Will Mercury ever become locked to the Sun?

The Mercury year is between 1 and 2 days. Has it ever been greater, and will it eventually become "tidally locked" with the Sun?
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1answer
31 views

Calculation of time delay in NASA's STEREO project

I'm trying to solve this task: Astronomers recently managed to get an image of the entire surface of the Sun for the first time. This became possible thanks to the STEREO project. In 2006, two ...
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2answers
140 views

2 points on Earth’s surface, 1 second apart in time

I’m hoping to find a method (probably some modeling software?) that would allow me to find pairs of locations on the Earth’s surface that occupy the same point in space relative to the sun, one second ...
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1answer
141 views

Calculate lines of equal solar altitude

I'm attempting to calculate lines of equal solar altitude, essentially a generalized case of the Earth terminator for solar altitude $ h $. For a given sun position with declination $ \delta $ and ...
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62 views

Is it completely false that the Sun does not revolve round the earth? In what sense? [duplicate]

This is a very naive question but I never fully understood this. For a system of two binary stars moving under the influence of their mutual gravitational forces revolve around their common center of ...
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2answers
76 views

defining the period of an year on earth

While it is much simpler to define the duration (time) of ONE complete day (for earth), by simply calling it to be the period between sunrise to next sunrise (which we have currently divided into 24 ...
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4answers
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How else can a star form, other than gravitational collapse?

I read this paragraph on the Sun's page on Wikipedia: [The Sun] formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most ...
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0answers
28 views

which fraction of the solar radiation corresponds the blocked part by Venus at its transit upon he sun?

Well, asumming that Venus orbits the Sun at 0.7233 AU and its diameter is 12,104 km, I can conclude that its angular diameter seen from the earth is ~1', then its represents ~1/31 part of the angular ...
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1answer
114 views

What exactly will happen when the Sun leaves the main sequence? I know it expands to a red giant twice, but what happens exactly? What's the timeline? [duplicate]

I've seen numerous claims surrounding this, with some claiming the expansion of the Sun from its end-main sequence radius to its peak red giant radius will take over 1 billion years, while others ...
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0answers
52 views

Solution of stellar structure equation for Sun in Convective Zone

Consider the following problem: Sun has a convection zone from $0.7 R_\odot$ to the solar surface, when $R_\odot$ is the radius of Sun. If the matter is marginally convectively unstable and the ...
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2answers
3k views

Is Jupiter warming the Earth? (Earth, Sun Jupiter system)

If Sun-Jupiter baricentre is outside the Sun, does that mean the Sun is orbiting around that point too right? Then the Sun shouldn't be nearer to the Earth at some point during the Sun-Jupiter orbit (...
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1answer
98 views

Path of sun in the sky on a planet with no axial tilt

Some sources online (e.g. this, see section "Effect of Earth’s Eccentricity") claim that if the earth's axis was not tilted, then the analemma would have the shape of an ellipse/oval. I ...
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1answer
79 views

What would be the effect of a large solar flare on motor vehicles?

With the solar cycle now leading to an increase in flare activity, one naturally starts to think the effects of a large solar flare heading this way. While major flares like the Carrington Event are ...
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1answer
30 views

What online tools are available to investigate and classify solar eruptions?

I was just casually browsing when I came across a link about at recent solar flare. So I went to investigate at SpaceWeather. There it was stated: Looking further down the page it seem to say that ...
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1answer
185 views

Is the claim that the star Sirius does not precess like other stars true?

There is this popular claim on Internet that the star Sirius does not precess like other stars. The idea comes from mainly Greeks and Egyptians using Sirius to track seasons, as part of the Sothic ...
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2answers
207 views

What was the day of the week for the total lunar eclipse (saros 61) that occurred on April 14, 32 AD?

I am interested to know if there is convincing "astronomical" evidence/data to pin down the exact day of the week for the total lunar eclipse of April 14, 32 CE. I am hoping that perhaps ...
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1answer
53 views

When could solar eclipse happen in a way that Sun's disk is diminishing from below?

I'm trying to solve this task: During a solar eclipse, an observer noticed that the diminishment of the Sun's disk began directly from below. Where and when could this be? Concerning "where&...
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1answer
164 views

What would happen if the Sun, Moon and Earth were isolated?

I am curious to know what would happen to Earth and life on Earth if all other heavenly bodies outside of our Sun, Moon and our planet Earth ceased to exist in some non-destructive way? (this includes ...
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2answers
120 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 ...
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1answer
42 views

Solar Rotation Varies with Latitude. Effects?

From the Wikipedia article of "Solar Rotation": Solar rotation varies with latitude. The Sun is not a solid body, but is composed of a gaseous plasma. Different latitudes rotate at ...
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1answer
37 views

What would be the effects of a -400 nanotesla geomagnetic storm on modern electronics? [closed]

After reading the Wikipedia article on geomagnetic storms, I'm curious about what the effects of a -400-nanotesla-minimum geomagnetic storm would be on modern military and consumer electronics. The ...
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1answer
36 views

The Sun's motion around the galaxy [duplicate]

As the Sun orbits the Milky Way, I understand that it also moves up and down through the plane of the Galaxy. How long does this movement take and can we tell where we are in the current cycle.
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1answer
230 views

Is there molecular hydrogen in the Sun's atmosphere? If so, how much, and how was that first determined and measured?

I don't have a license to practice chemistry, but I'll convert Wikipedia's bond dissociation energy of 435.7 kJ/mol to eV by dividing it by $C / N_A$ where $C$ is 1 Coulomb and $N_A$ is Avogadro's ...
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1answer
128 views

What is the percentage of ortho- vs. parahelium in the sun?

Parahelium (P) has its 2 electrons with opposite spins and S=0. Orthohelium (O) has parallel spins and S=1. The energy levels of P are a little bit higher than O. Maybe this leads to easier building ...
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1answer
114 views

How did the ancients know the constellation in which the sun is located?

The zodiac constellations lie along the plane of the ecliptic. In Spring equinox, sun lies in Pisces constellations. So Pisces is not visible during the day (because the sun light) and not visible in ...
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1answer
100 views

In which town is the length of the day bigger on 23 of September?

I'm trying to solve this task: Moscow and Kazan are located on the same parallel. In which of them the length of the day is bigger on 23 of September? In Kazan the sun will rise earlier, because it'...
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2answers
2k views

What is the probability of life having developed or going to develop in our solar system another time?

I'm sorry I am not quite sure this question satisfies this point: Questions that are purely hypothetical, for example a question such as 'Could a black hole destroy the universe' or 'What if our ...
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1answer
93 views

Spectral lines of the Sun?

If I remember correctly, the pp chain and (partially) the CNO cycle are the dominating set of reactions in our Sun. On the other hand, the composition of the Sun has many more elements/isotopes than ...
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2answers
87 views

Is it possible for the Sun to lick the Earth with its flames?

The Sun ejects bursts of high-velocity matter, like fiery tongues reaching out. The Sun's magnetic field is able to deliver these bursts at different spots. Sometimes the flames are pulled back in by ...
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4answers
5k views

What it the outer part of the sun, that we see with our eyes, called?

When we look at the sun with our eyes it seems much larger than it actually is. When we use a solar filter we are seeing what the sun actually is. So, what is the name of the thing the solar filter is ...
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0answers
31 views

What is the size of the universe? [duplicate]

Will as a result of the continuation of technological progress in the twenty-first century more perfect telescopes or other astronomical instruments that will allow to know what is on the surface of ...
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2answers
128 views

If a 1x1x1 Cube from the Sun's surface were scooped , and taken to a sufficiently cold point, say near Jupiter, what would happen to the cube?

Let's assume for the sake of this question that the 1x1x1 cube was scooped by unknown methods, and is instantly brought to somewhere close to Jupiter's orbit without any harm or any change to nearby ...
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3answers
327 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 ...
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1answer
90 views

Where will the frost line be when the Sun becomes a red giant and what effect will it have on the solar system?

I understand the frost line is currently about 5.2 AU and earlier in the solar systems formation was 2.7 AU. But when the Sun becomes a red giant the frost line should move outward. I understand the ...
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1answer
131 views

Confusion when calculating the length of the day

I'm trying to solve this task: Tula and Moscow are located on the same meridian. In which city length of the day is bigger on 22 of June? 22 of December? I was thinking like that: we need to ...
5
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1answer
36 views

Strength of the relationship between very large solar flares, coronal mass ejections, and solar proton events?

In the years 774-775 and 993-994, there were large peaks in Earth's atmospheric radiocarbon (14C) concentration. While the cause was initially disputed, Mekhaldi et al.'s 2015 study of annually ...
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1answer
88 views

How big is the Lorentz force on the Sun?

The LOFAR observations have made an estimate of the magnetic field of the Milky Way. The value in our region is very small. About 1/1000 of the Earth magnetic field. The Earth and the Sun move at a ...
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1answer
166 views

What are Ellerman bombs and how can we identify them?

Have you ever heard about Ellerman bombs? Spaceweather.com talks about them on their news page. You could see some of them around sunspot AR2835: Ellerman bombs are magnetic explosions about one-...
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4answers
4k views

Why doesn't the Sun wobble towards Jupiter instead of away from Jupiter?

This is the page I am referring to. It seems counterintuitive to me that the Sun should be on the opposite side of the barycenter's wobble. I realize I am wrong, but I cannot see why I am wrong. Can ...
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1answer
51 views

Sun right ascension and declination at date with different values on different calculators and also with my implementation

I'm reading the book "Practical Astronomy with your Calculator or Spreadsheet 4th Edition" implementing its formulas with C++. Now, I have implemented formula 47 "Calculating orbits ...
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1answer
93 views

If the sun would be two times as big and with the same power output would temperature on Earth change? [duplicate]

Suppose the suns radius is increased by two. And suppose its emitted power doesn't change. Will we notice this on Earth? It will seem twice as big but apart from that what will we notice(if anything). ...

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