Questions tagged [the-sun]
Questions regarding the closest star to Earth, at the centre of the Solar System.
717
questions
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77 views
Why are there different time estimates for a solar photon to reach the surface of the Sun?
Some estimates range the photon journey from 10,000 to 170,000 and even millions of years, but only consider the path from the sun's core to its surface. This is called 'Random Walk Problem' and ...
-2
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0answers
48 views
Sun and moon on one side of sky [closed]
We can see sun and moon at the same timeninnsky but Can Sun and Moon be seen on the same side in sky any time ( same time) ever?
1
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0answers
101 views
Would a future Dyson sphere or swarm around our Sun actually be beneficial to people on Earth? [closed]
A Dyson sphere or swarm's function is to harvests most of a star's energy, correct?
However, a future Dyson sphere around our Sun would also block the Sun's rays from reaching Earth. Wouldn't it ...
3
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1answer
95 views
What is this pale blue dot in a daytime photo of a Sun halo? [duplicate]
This photo of the sun behind a cloud was taken on the south coast of England in early May 2021 using an iPhone 11. A halo is visible which I think is the 22-degree halo. However, the photo also shows ...
10
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1answer
174 views
Do radio telescopes see other stars better at night?
As you know, we don’t see stars with the naked eye during the day because of the visible glare of our Sun.
As I understand our Sun emits radio frequency waves, too. Is there a radio ‘glare’ from the ...
2
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1answer
71 views
Is it fair to describe a solar flare as a big lightning strike on the sun?
Solar flares and lightning strikes are both kinds of electric discharges.
A lightning strike is a sudden discharge of electrical energy between an electrically charged cloud and another object, like ...
0
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3answers
100 views
What's the minimal argument I can give to reject The Geocentric Universe?
I'm new to Astrophysics, So pardon me if you find it silly to ask. I was just started reading about the basics of astrophysics. I read about the Greek Tradition, the concept of a geocentric universe. ...
1
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0answers
31 views
Finding Observer Latitude/Longitude - In Simple Terms
I was wondering if someone could explain to me in simple terms how to determine the observer latitude/longitude at a given location. For instance, if an observer is positioned at Cleveland, Ohio, how ...
1
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0answers
65 views
Physical properties of the stellar corona?
I am after the basic physical properties of the corona of a star, here some questions for which I would like to have an answer, even only for a subset of them:
I know some things about the corona of ...
21
votes
2answers
3k views
How hard is it to find the Sun's “sisters?”
As @ProfRob stated in his excellent answer regarding the ejection of the Solar System's fifth gas giant,
It is for similar reasons that, even though the Sun was probably born in a cluster of $\sim 10^...
1
vote
1answer
37 views
Is it easier to see the young moon when it's closer to the sun?
With the naked eye, would it be easier to see the moon when it's close to the sun, because it might reflect some more light (or not, I'm not sure) or farther from the sun because the sun shines ...
0
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0answers
42 views
sdo.gsfc.nasa.gov website offline?
Is the NASA solar dynamics website offline? If not how can the daily sun 'movies' be downloaded from https://sdo.gsfc.nasa.gov/data/dailymov.php?
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0answers
25 views
Is GAIA the only game in town for looking at quadrupole gravitational deflection of light?
From Gerry Gilmore (2018) Gaia: 3-dimensional census of the Milky Way Galaxy
4.4 Fundamental physics
Relativistic effects are highly significant for Gaia measurement accuracy, with
tests of General ...
0
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0answers
19 views
What is time period of sun revolving around the center of Milky Way? [duplicate]
What is time period of sun revolving around the center of Milky Way?
14
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1answer
2k views
Does bending of light around the Sun depend on the wavelength?
If the energy of light is high, does its curvature differ from that of low-energy light around the Sun? In other words, if the wavelength of the light is shorter than another wavelength of light, then ...
2
votes
1answer
39 views
How to determine the formula to calculate this position of reflected Sun?
I created a geometrical simulation of how the Sun is reflected on a wall along the day and along the year, using Geogebra:
https://www.geogebra.org/classic/dckhbc8h
Playing with parameters, I found ...
2
votes
2answers
123 views
Open source code for the maths behind a heliostat?
Theoretically, using a Raspberry Pi, (at least) one mirror, and two motors, one should be able to build a heliostat, i.e. a device which redirects sunlight to a fixed spot, like a scrub in the shadow ...
4
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0answers
22 views
Help understanding ring diagram analysis used in helioseismology
I need help understanding something. In global helioseismology we study the modes directly (stationary waves characterized by 3 integers numbers: $n$, $l$ and $m$). As the angular degree $l$ becomes ...
9
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1answer
68 views
How much water on the earth is made from hydrogen comes with solar wind?
A great fraction of solar wind is protons or Hydrogen ions. Some part of it is captured by Earth. I am wondering how much water in my half a liter cup is made of hydrogen from the Sun.
7
votes
1answer
386 views
How to find the shape of an orbit
What is the minimum information I need to be able to draw the shape of an orbit of a body that orbits the sun? With this information how can I figure out the shape of its orbit?
4
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0answers
93 views
How to design a static heliostat?
An heliostat is a device capable of reflecting the sun in a fixed point while the sun itself moves into the sky, thanks to a moving mirror.
But this company astonished me with its invention: a static ...
9
votes
2answers
2k views
What do astronomers do different now that they know about fusion of the Sun? [closed]
I would like to know how knowledge of the fusion in the Sun has changed how astronomers explore the universe. What do astronomers do differently now that we know that the Sun’s use of proton-to-proton ...
2
votes
3answers
74 views
How to determine when Sun/Moon is aligned to two location on Earth's surface?
I would like to make a photo to Moon/Sun when it is very low on horizon, so if I make the shot far away from an object on Earth surface, it appears as big as the Sun.
But how can I calculate the right ...
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votes
2answers
124 views
What pulls the Sun above the galactic plane and pulls it below the galactic plane?
Since the sun climbs above the galactic plane and it even dives below the galactic plane we can't deny that it wouldn't climb upward unless there is something above the galactic plane that pulls it ...
14
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3answers
1k views
Formation of elements in the Sun other than helium
I just learned that the Fraunhofer lines of the Sun's spectrum indicate that the Sun contains various elements other than just hydrogen and helium (for example, Na and Fe) but don't the Sun's p-p ...
3
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3answers
185 views
Spectrum of stars
If some specific metal is shown in a star's spectrum, does it indicate that the star has that specific metal? For example, the Sun, a G2 star, shows medium strength of Ionised Calcium in its spectrum, ...
8
votes
1answer
570 views
How much matter was ejected when the Solar System formed?
Assuming the accretion disk model for the formation of the Solar System, the most important problem, according to wikipedia, is "how the material, which is accreted by the protostar, loses its ...
2
votes
1answer
87 views
How close would an LED have to be to your eyes to be as bright as the looking at the sun during midday?
I wonder if it is possible to have an LED screen bright enough to simulate the brightness of our sun from Earth, and if so if it could be made small enough to fit on a laptop screen.
9
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4answers
711 views
Is there a term for “path of the Sun at a given point of the Earth”
I want to buy a house and I'm asking myself what quantity of daylight the various sides of the house receive.
I know the house is roughly oriented in the east-west direction.
But I'd like to know the ...
1
vote
1answer
156 views
Why does Wikipedia state that the Solar System has one unconfirmed planet?
I was looking at exoplanets on Wikipedia, and found this surprising information:
The table states that the Sun has 8 planets (obviously) and one unconfirmed planet. Why is this here? I think it's ...
3
votes
0answers
57 views
How is the incidence angle of the Sun related to the lean angle of the Cooks pines?
Auracaria columnaris (Cooks pine) on average lean towards the equator. Most of the pines in the Northern Hemisphere lean southward and most of the pines in the Southern Hemisphere lean northward.
...
16
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2answers
2k views
Is it possible that the Sun and all the nearby stars formed from the same nebula?
I was looking at a map of our local stellar neighborhood, and it occured to me, the stars are really close, if one compares them to the size of some nebulae. So can it be, that the Sun, Alpha Centauri ...
5
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1answer
53 views
How can astrophysicists discriminate between pp-chain solar neutrinos and CNO-cycle ones?
Astrophysicists at the Borexino experiment in Italy have recently claimed that they have detected CNO-cycle neutrinos coming from the Sun.
It was the Cover story for the November 26 issue of Nature.
I ...
0
votes
1answer
40 views
What is the degree of reflection of light from sun to the moon? [closed]
As Moon reflects the light from the sun it must have an ANGLE OF INCIDENCE and ANGLE OF REFLECTION...
What Is the angle of reflection then?
3
votes
1answer
137 views
How much solar energy concentrates at Jupiter's focal point via gravitational lensing?
How much solar energy concentrates at Jupiter's focal point via gravitational lensing?
2
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0answers
30 views
Classical Mechanics : Interaction Sun Radiation Pressure - Gravitation
I have a theoretical problem that merges the effects of a gravitational field and the Sun radiation pressure. The problem goes as follows:
A spacecraft orbits the Sun in absence of any other body ...
1
vote
1answer
56 views
Estimating Sun luminosity from first principles
In a lecture, it was claimed that luminosity can be estimated by dividing how much energy there is in the Sun with the typical time it takes for a photon to get out from the centre of the Sun to its ...
5
votes
1answer
217 views
Which will destroy the Earth first: the Sun or Jupiter?
The sun is expected to grow in brightness over time, slowly heating the Earth until the oceans evaporate, leaving the planet uninhabitable.
Jupiter is the source of the largest perturbations to Earth'...
8
votes
1answer
397 views
If the fifth gas giant in the early Solar System was completely ejected, where would it be now?
I've read about the possible 5th gas giant in the Solar System, and about its ejection about ~100 million years after the formation of the Solar System. However, I have not seen anything about its ...
0
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0answers
22 views
What if a planet or another star or ¨sun¨ collided with our sun? [duplicate]
Stellar collisions are a well-studied phenomenon in Astronomy, albeit mostly theoretically. In some cases the merger of two low-mass stars can result in a new star plus new planets around it.
But what ...
0
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1answer
138 views
Will there be any more planets come into our solar system and make it their “home”?
Could we have more planets come into our system and get trapped by our suns gravitational field and rotate?
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2answers
98 views
Sunset moonrise what happens in between?
Here in south London I have just seen that the sun will set at 16:45 hrs but the moonrise does not happen until 2hrs later 18:45 hrs what is happening in this two hour void, will it be too dark to see?...
3
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0answers
66 views
From what distance could the Sun's planetary nebula be seen entirely with free eye?
When collapsing to a white dwarf, a red giant Sun would emit a planetary nebula. How far from the Sun would that nebula stretch at most?
Also: At about what distance could you see the planetary nebula ...
3
votes
1answer
30 views
Why is solar corona in visible light filamentary?
There is a video on YouTube (unfortunately in Czech) where Miloslav Druckmüller talks about structure of the solar corona in visible light. He explains that the filaments, clearly visible on his ...
3
votes
1answer
224 views
Significance of astronomical twilight
What is the significance of astronomical twilight? Astronomical twilight is when "the geometric center of the Sun's disk is between 12 and 18 degrees below the horizon" , but what, if any, ...
13
votes
4answers
3k views
Is it at all possible for the sun to revolve around as many barycenters as we have planets in our solar system?
Though it is understandable that the sun and the earth may be revolving around a barycenter, but, if so, not only the sun and Jupiter should also be revolving around some barycenter, the same should ...
25
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3answers
4k views
Why can't stars be multicolored like gas giants?
Gas giants like Jupiter and Saturn have bands of different colors in their atmosphere. These are due to the rotation of the planets. Stars rotate too, so why do most stars have patches/blotches of ...
0
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1answer
147 views
If it only takes 8 minutes for that light to reach the Earth, what took up most of the time? [closed]
If it only takes 8 minutes for that light to reach the Earth, what took up most of all that time to get to the Earth?
3
votes
2answers
428 views
Does the earth spiral around the sun's movement/motion path?
I have watched the following video (How Earth Moves by Vsauce) regarding how earth moves:
Here are some screenshots:
I have some questions:
Does the earth spiral ...
2
votes
0answers
62 views
How to calculate the limb darkening $\mu$ value
I am reading about limb darkening and I am very confused how to find the value of $\mu$.
It states it can be found by $\mu = \cos(\gamma)$, but I am lost how $\gamma$ is found, or what it represents.
...
