Questions tagged [the-sun]

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

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2
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2answers
178 views

Is it possible that a satellite creates a forever eclipse? [closed]

So, to add a bit of context, I’m doing the NaNoWriMo challenge, which consists of writing a novel of 50k words in one month. My whole idea is based around the following question: What would happen if ...
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0answers
161 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? ...
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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?
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Tracking a heliographic coordinate on CCD

Given the latitude and longitude of a heliographic coordinate, I want to place the point on a CCD image and simulate its motion for a particular duration. Though I am able to track the motion of a ...
4
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3answers
1k views

Solar visible light spectrum

So the visible light from stars can be used to identify the elements in that star by looking at the spectral emission lines and comparing those lines to emission lines of various elements (and their ...
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0answers
107 views

Sunspot heliograph to generate random numbers for bitcoins? [closed]

If this is off topic, please change it to world-building. Is it possible to make a low cost heliography telescope, which is not digital, and which can be used to generate an worldwide numerical ...
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0answers
112 views

At each stage and during each transition of the Sun, is there a region the Earth could theoretically orbit and support life? [closed]

As I understand it, the Sun will transition from its current phase as a 'yellow dwarf', to a red giant, and finally to a white dwarf. Even during these phases I understand there are transitional ...
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3answers
6k 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 ...
3
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1answer
114 views

Would the heliosphere disappears if our sun becomes a white dwarf?

Just curious I like to know if one fine day our Sun turns into a white dwarf at the later stage of its life, would the magnetic bubble, heliosphere gets thinner and eventually disappear? also at this ...
2
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1answer
66 views

What causes the raise of temperature in the outer layer of a red giant when the core gets contracted?

A star emits energy through the fusion of hydrogen to helium in the core through the proton proton cycle or the carbon nitrogen cycle. Over time, hydrogen in the core is increasingly burned, which ...
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5answers
6k views

Why doesn't the Sun explode?

I know stars explode because of the fuel causing a fusion compound pushing it apart and the fuel runs out and it 'bounces' for lack of a better term. Given the fact that more massive stars are ...
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1answer
2k views

Why is Chandrasekar Limit expressed relative to Sun?

In 1931, Chandrasekhar was able to show that there is a certain critical mass (Chandrasekhar's limit) beyond which a white dwarf cannot exist, since the electronic fluid at that point cannot support ...
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1answer
447 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 ...
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2answers
98 views

Can we, with arbitrary precision, calculate what's the place on earth that's closest to the sun on a given day?

Can we, with arbitrary precision, calculate what's the place on earth that's closest to the sun on a given date? If so, what's the math like? Say, if I wanted to calculate this within 1m, 10cm or 1cm ...
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2answers
269 views

Mountains on the moon during solar eclipse?

I ask myself the reason of why the sun in not uniform on the edge of the moon at this moment of the eclipse (cf. picture) is not unifom is because of the mountains of the moon ? Or can it due to ...
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1answer
2k 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. ...
0
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1answer
139 views

A real light source, or an artifact?

I was taking shots of the 2017 eclipse using my D7200 camera with a 1000 ND filter. As I was going through the pictures after downloading them to a pc, I noticed that there's what appears to be a tiny ...
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1answer
2k views

Does the Sun have any atmosphere?

Does the Sun have any atmosphere of its own? Is it just like the atmospheres that the planets have.
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2answers
715 views

On the Equator, why are the shortest shadows seen at 11:32, and not at Noon?

On Equator, why do objects cast the shortest shadows at 11:32 and not 12:00? For instance, this happens in Costa Rica.
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2answers
99 views

On the day of total solar eclipse why was early sunrise observed in India?

I am a middle school teacher from India(UTC+5:30). On August 21, 2017 morning at (17.385044, 78.486671) we observed an unusually early sunrise. It felt like its 7'O clock in the morning at 5:45 AM. ...
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1answer
262 views

Getting Solar Noon from Sunset and Sunrise

I've seen the solar noon formula described as snoon = 720 – 4*longitude – eqtime. I'm curious if it is equally reliable within a relatively small margin of error (+-...
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2answers
14k 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?
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1answer
184 views

At what distance would it be safe for humans to stare at the sun?

Let's say we could travel anywhere in the solar system, at what distance would it be safe for a human to stare at the sun (without eye protection) and not get eye/retina damage? (Not sure where this ...
4
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1answer
126 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 ...
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1answer
102 views

Might someone see changes to the corona during a solar eclipse?

I've seen many pictures of the corona during a solar eclipse, and the structure and delicacy is amazing. Clearly, the appearance would change over time, depending on the fine details of the solar wind ...
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1answer
91 views

Where can I still find solar film?

I, like many others, am excited to see the eclipse. I want to view the eclipse through my telescope, however, I don't have any solar safety equipment for solar viewing and I cannot find any online ...
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0answers
53 views

Will you be able to see the corona in a 90%+ partial eclipse? [duplicate]

I live in Champaign, Illinois (see map) and am planning to watch the August 21st solar eclipse. This community is within the 95% totality range, but not within the path of totality. Will I be able to ...
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1answer
203 views

Do other G-type stars follow an 11-year cycle of activity?

Our Sun follows an 11-year cycle of low-to-high activity. During high activity, there are much more sunspots and much higher chance of flares and other disruptive behavior. Can we observe the ...
5
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1answer
1k views

Why shouldn't you look at the Sun through a camera using eclipse glasses?

One of the NASA approved eclipse glasses manufacturers has the following warning on one of their eclipse glasses: Do NOT look through a camera, telescope or binoculars with ANY eclipse shades on! ...
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1answer
398 views

Converting Earth Moon Barycenter coordinate to Geocentric coordinate

I have Earth Moon Barycenter coordinate (J2000) generated from VSOP2013 in Astronomical Units, ...
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1answer
728 views

How to convert VSOP's xyz coordinates to heliocentric spherical lbr coordinates?

I ran VSOP2013 in Fortran, and I now have the following position $x, y, z$ as well as velocity $v_x, v_y, v_z$ data. How do I convert the position to heliocentric ecliptic spherical coordinates $l, b,...
2
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1answer
521 views

How long was an early Earth year? [duplicate]

Roughly how long did it use to take for the early Earth 4.5~ billion years ago to complete one revolution around the Sun? (I know the Earth was spinning much faster, so a day would only take 2-3 ...
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1answer
634 views

Is there a difference between the solar elevation angle and sun declination?

I need to use the sunrise equation but one of the variables is the sun declination. On the other hand, I have the values for solar elevation angle that I need. Are they the same thing?
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2answers
377 views

Which would be safer: removing hydrogen or adding hydrogen to our sun?

If we want to extend the lifespan of our habitable zone safely, would it be safer to institute a yearly 'tax' on our suns outer layer of hydrogen, or a yearly 'subsidy' to our suns outer layer of ...
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1answer
506 views

Other than relative temperatures, is there any difference between a red sun and a yellow sun?

As time goes by, explanations for unusual things that exist in fiction get disproven. We know radiation probably isn't going to create a Giant ant that destroys everything, we're pretty sure we can't ...
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1answer
2k views

How can I calculate the time between sunset and actual darkness?

I would like to know the time it takes to go from sunset to dark based on GPS location. In addition, ideally I would also like to have a formula that determines the percentage of sunlight at each ...
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1answer
174 views

How much has the apparent magnitude of the Sun changed?

Did the apparent magnitude of the Sun change in the past 1000 years or so? If so, for what reasons?
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2answers
1k views

Is the Sun prograde or retrograde with respect to the rotation of the Milky Way?

I recently learned about the terms prograde and retrograde. I've seen these terms used to describe the rotations and orbits of moons with respect to their planet, and planets with respect to their ...
4
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2answers
718 views

Could the Earth survive a red giant Sun?

So my question is that, is not a lie that we are flying away from the sun slowly, that is increasing by time because the sun loss mass, so when the scientist usually talk that we will get swallow by ...
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0answers
413 views

Complete Sun altitude-temperature graph?

I found a bunch of partial graphs. For interior: src For surface: src The closest thing I could find that would cover more than innermost piece of corona is for sigma binaries. As if solar corona ...
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2answers
1k views

How far could be an object from the Sun and still be under the influence of its gravitational field?

I'm trying to see how far can our star reaches with its gravity. I'm asking if anyone could give info as to what's our star's limit or the furthest object found in our solar system.
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2answers
293 views

The Sun or Our Galaxy revolves around what? [duplicate]

Like every planet they are in orbit of something or another planet like our solar system every planet revolves around the sun, my question is: what's the name of the planet or object which the sun ...
3
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2answers
746 views

Umbra, penumbra and antumbra

I'm trying to understand following schema of the wikipedia page here. Image subtitle is "Umbra, penumbra, and antumbra, for a lunar eclipse". Distances and sizes are not to scale. If distance ...
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0answers
57 views

How to get SOHO Satellite images' coordinates?

I'm working with images from LASCO C3 coronagraph I'm able to download pictures from LASCO C3 using this form https://sohodata.nascom.nasa.gov/cgi-bin/data_query Then, I want to do some analysis of ...
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1answer
680 views

Determining sunrise and sunset times based on azimuth and elevation

If I observe the sun and measure the local azimuth and elevation, and I also have my latitude, can I calculate the local sunrise and local sunset times? If so, how would I calculate it? Further, can ...
2
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1answer
2k views

Moon and Sun UV Light

How much ultraviolet light comes from the moon at night and from the Sun during the day? I am interested in using a UV camera on a robot to see the UV from the sun/moon to do robot localization.
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0answers
37 views

Is there a connection between Jupiter's orbital period and the Sun's solar cycles? [duplicate]

The cycle of solar maximums and solar minimums are each about 11 years, which is close to the orbital period of Jupiter. I thought it was a numerical coincidence, until google turned up some results ...
4
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2answers
307 views

Appearance of sun at geologic past

After origin of Earth ( 4.54 billion years ago ) to today; what are the changes through-which the sun undergone with time? , ( if seen from Earth. ) I'm doing some palaeobiology-landscape rendering; ...
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1answer
49 views

Change of time in vernal equinox by altitude from the Sea level

vernal equinox for a very high tower ($h_1>3000m$) in a city ($\lambda , \phi$) in altitude $h_1$ from the sea level is 8:00 Local time. Does this time change if we go to another altitude in that ...
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1answer
84 views

Effect of gravitation [closed]

When the sun reaches close to the centre of the Milky Way galaxy while revolving around it (like the earth closes down on the sun while revolving around it, perihelion), will the gravitational effect ...