The sun Definition and 634 Threads

What is the brightness of the sun compared to the sky that it lights up? I have a solar filter that only sees the sun. I just wonder if it is needed to be so dark that I can't see the sky anymore. I have plenty of camera options left to shorten exposure even with a filter a fraction as dense...

The human body is made up of mostly oxygen, hydrogen, nitrogen, carbon, calcium, and phosphorus. Less than 1% is sulfur, potassium, sodium, chlorine, and magnesium. If a human body was teleported to the surface of the sun, what would happen to these elements? Which ones would cease to exist...

I called the point E1 the point where Earth was at Feb,11 1990 and E2 at 30, Dec 1991, S for Sun and M for Mars and r for the Mars-Sun distance. Since we got a whole sidereal period between both alongation, I assumed Mars was on the same point in space (wrt Sun). I think I got the triangles...

Whilst perusing a D&D forum, I stopped to answer a question someone put out which was "what would happen if we used the gate spell to open a portal to the middle of the sun?" I replied (this was a while ago) and whilst I'm reviewing it, I am troubled by the fact that this uses such high forces...

IIRC, the Sun's gravity was calculated by Einstein et-al to provide a 'focus' about 550 AU out. Current value is ~542 AU. Aside from effects due solar oblateness, frame dragging etc, may I assume this value also applies to eg neutrinos, gravitational waves etc etc ??

Enjoy the season. And let the southern hemisphere be on notice: We're taking the sun back!

What is angle of Sun June 21 & Dec 21 at zip code 37129. I need lowest angle & highest angle and probably angle of sun about Feb 20. Google word search shows nothing. I am probably need using correct word search to find what I want. Several years ago I accidently found a calendar that showed...

The equivalence principle tels us that we cannot distinguish between gravity and an accelleration. using that fact one can reconstruct the bending of light along the sun, but only half of it results from the equivalence principle together with the gravitational field around the sun. Is it...

hello guys, sims back again with another question.. I don't understand what is up with question (b) cuz like.. to get ##v_esc## we assume that at ##r_0=\inf## ##v=0## but now if I assume at ##r=1.5E8## that ##v=0##. And then find ##v_esc## from the following: ##\frac12*mv_{esc}^2 -...

Hello, I have a question. If a star tracker in space faces the sun directly then could it be possible that the sun completely burns the image sensor? To be specific we are a student satellite team (Student satellite program IIT Bombay) developing a star tracker and we don't have an exact idea...

I would like to know why the sun seems so bright. I know why the sun is a great source of light but that’s not what I’m asking. Why do my eyes perceive the brightness. Is it based on the number of photons that enter my eyeball? The more photons the brighter I perceive the light to be...

Is the Earth getting closer to the sun from gravity?

Hi. I have this idea that might be useful for celestial navigation. If you were on a random place on the Earth, and you had a way of measuring the altitude of the sun above the horizon, at a precise moment, could you then predict the complete path, such that you could determine the altitude at...

I reviewed the derivation / solution of that GRT problem and do not see any dependence on the wavelength of the light. Is that correct, or am I missing something? This makes me wonder about my understanding of how prisms work. How or why do longer wavelengths go slower in glass than shorter...

I'm reading about the engineering of the James Webb and it surprised me that the temperature difference will be about 318 degrees from one side of the telescope compared to the other (85 C on one side and -233 on the other). I didn't expect space to be that hot about a million miles further...

Early in the pandemic there was, at least in the U.S., a concern about toilet paper shortages. It all seems so quaint now but there were actually runs on t.p. in supermarkets and people were hoarding it. There are of course other ways to clean up afterwards. I reckon that most people in the...

Science involves not just knowing what you know, but accurately estimating how sure you are of what you know and having a decent understanding of what you don't know. There are two known true planets closer to the Sun than Earth (Mercury and Venus, neither of which has a significant moon), both...

In many text, the Sun is referred to as a low-mass star, yet it is also referred to as a medium-mass (or intermediate-mass) star in some other text. Which one is "correct"? What is the range of low-mass vs medium-mass? Is it really just low-mass vs high-mass and that medium-mass is just the...

Einstein first calculated the bending of light rays that are touching the sun as 1.75 arc-sec. For the calculation I refer e.g. to https://www.mathpages.com/rr/s8-09/8-09.htm I know that spatial angles in general relativity don’t have an intrinsic value (are not invariant). They are dependent...

An Analemma is the shape that arises from taking a picture of the sun everyday at the same time of the day. This shape also have depth to it since Earth's orbit is elliptical, showing what looks like an wobbly orbit. Isn't this the "real" orbit of Earth around the sun?

Some estimates through calculating the sun mass loss and increase in mass loss say that the white dwarf phase of the Sun will have roughly about 50% the current mass of the Sun (not sure about it). Whatever the actual mass loss is going to be, assuming that the 50% mass loss is true, where would...

Basically, I'm wondering if there have been any attempts to calculate/model what the radius of the sun should be based on gravitational, thermal, and electromagnetic pressures. If there has, where can I find the calculation/model, and how closely does it match the actual radius of the sun...

Are the granules that we see on the Sun actually in the photosphere? Or are they actually just the top of the convection zone, with the photosphere beginning just above them? Or is the photosphere simply defined as the top edge of the convection zone where the granules are present, having...

A photon is different from an electron. At least by the fact that it is neutral. But, flying into the silicon lattice, it knocks out an electron and takes its place. That is, it becomes an electron. How does such a magical transformation happen? I may be wrong, but I think that a photon becomes...

I've always wondered why. Would the reason be that the air cools but the amount of moisture stays the same... which makes sweating less effective... which means no cooling effect even though the air is technically cooler.

The book says the actual measured deflection from some experiments is about ##9\times 10^{-6}## radians, and this is double the value that a naive computation returns because of general relativity effects. So I guess my goal is to compute a number that looks like half that. If suggests to do it...

A little off subject, but a few years ago I went out fishing just as the sun was rising. Perfect morning, not a cloud in the sky. The moon at this stage, was still clearly visible and both the moon and the entire sun were sharing the same sky. Which is pretty cool but what to this day makes me...

Hi. I'm new and hoping for some discussion. I've been looking at some physics at home on my own while Covid-19 restrictions keep me off work. I'm not registered as a student anywhere and so don't have any chance to chat with other students or university staff. Hence, I'd be grateful for some...

I had read that the Sun will become a white dwarf and then gradually cool down to a black dwarf, but this figure at Wikipedia says it will go supernova. (Yes, I know I should not trust Wikipedia, which is why I'm posting the question.)...

Hi, In my textbook it says that if you consider the electrostatic repulsive barrier that protons in the Sun need to overcome in order to get into the range of the strong nuclear force to fuse together then it fails to fully account for the measured power output of the Sun. It says that the...

when electron is moving around it like it accelerate and so it create magnetic field. and when mass accelerate it create gravity radiation , we also know that the gravity is not actuall force and it just change the time so when the Earth move in 4 direction it change it path becuase time change...

I would like to understand, for a science fiction book idea, if there is a possibility to create a theoretical energy plant that would circle the sun and tap into it's core and drain energy from the core (to use for human needs) and in the process would "drain" the sun or "shorten" it's life...

Summary:: Given statement: according to one model of the sun, the central mass density is 1.53x10^5kg.m^-3 and the mean opacity at the center is 0.217m^2kg^-1 Given statement: according to one model of the sun, the central mass density is 1.53x10^5kg.m^-3 and the mean opacity at the center is...

suppose suddenly the sun disappears at a time t. at this arbitrary time t, the Earth should fling off tangentially to the point in its orbit at time t as there is no centripetal force keeping it in orbit. we know light takes about 8 minutes to reach the earth. so will humans on Earth experience...

Stunning and mesmerizing,

Summary:: At what distance from the Sun will the speed of the planet be equal to the average orbital speed? I'm not sure where to place this question, please move it in the right thread. [Mentor Note -- thread moved from the technical forums, so no Homework Template is shown] At what...

I’ve been watching =AT2AcUch2CYj2r40rQ431p1Rt1SQ-YzVLo-ryJHYFIT8s9ZlMJ5pcWH9lN17FRuz2eLTlNPVb4fP2yk4PPLqjJK_6lpeWheAbATLZd7foljjUg2sOFxm-mZbhhcw3G9ApCzWIWNjgBGcGjoXMqdW6Jv-Rb8P2yA']https://www.youtube.com/watch?v=l3QQQu7QLoM What is the scientific name of the enigmatic long linear dark features...

This might be total nonsense, but the thought popped into my head while I was trying to get to sleep, so I thought I see if I could find any advanced help with the following hypothetical: If light were instantaneous, how far from Earth would the sun have to be to cause a quark orbiting in place...

Let's suppose a solar electron moving directly towards Earth's equator at a high speed. This electron meets Earth's magnetic field, which points to the north, at a distance ten times the Earth's radius, where magnetic field is almost uniform. Which will be the direction this electron describes...

Probably a silly question and a simple one for yourselves which I can't figure out myself. Hopefully I can explain it properly. Lets say I am standing on the equator and the sun is directly overhead. I am probably in the middle of a desert and it's around 50 degress centigrade. Assuming I could...

How much brighter is the sun when seen from space than it is when viewed from Earth?

This is a question about GR. If the sun hypothetically disappeared in an instant, would our planet Earth immediately fly off into space or, would it continue to orbit for the 8 or so minutes that the light continues to travel to the surface?

The exercise is to compare numerical and analytical solution. I have worked out the code from earlier exercise (see code under this text), but I don't understand how the analytical solution works. I have tried to use the equation r(theta) = a(1-e^2)/(1+e*cos(theta)), which is OK but I don't...

The Earth's orbit around the Sun is an elliptical orbit. Why is that so? Does that mean Sun, much like Earth bulged at some points which makes the gravitational force between Earth and Sun stronger at some points and weaker at some comparatively?

So the sun is largely hydrogen atoms and those hydrogen atoms are undergoing fusion all the way up until they reach iron. My question is are the electrons orbiting around the nucleus just as they are in any normal object? Or is the sun just like a pool of electrons and protons floating around...

Continue reading...

I came across a question recently which involved calculating the change in wavelength of a photon between being emitted from the surface of the sun and arriving at the Earth. The method that was implied involved calculating the GPE's of the photon (assuming the photon to have a mass h/[c...

Pardon the very naive question, but why does the atmosphere in these gas giants seem to have, from a distance, a very clear, sharp and distinctive boundary? When one looks at Earth's atmosphere from space, it seems to have a fuzzy bluish boundary, gracefully vanishing into the black. I read...

If a (maxwells) demon were to snatch the core from the sun, what would the result be? would the remaining outer layers coalesce into a red dwarf and just continue on without much fuss? Would the core, removed from the sun, undramatically just expand out to become a red dwarf also? Just a silly...

I think this question is important so posting it here. To cut a long story short there is a person in our country who is totally anti-science and anti-Western citilization. He says science is a big lie. < remainder of post deleted by moderator >