The sun Definition and 622 Threads

Hey all, I think that I'm doing this problem correctly but I'm getting an answer that's a couple thousand Kelvins off. Sorry if I should have posted this in the "advanced" section. 1. Homework Statement Part of a flat region of Pluto has the Sun directly overhead. Its surface temperature is 58...

Hi, I am wondering. Is it possible to predict the amount of time dilation on the surface of the sun compared to the surface of the earth? Is this a correct question to ask, or have I made a bad assumption? Thanks in advance. Ayjay

The sun has no surface, but it appears to have a surface. I may recall that Feynman said that the apparent diameter is equal to the mean free path of a photon. That could be, but I don't get the relationship. Any help?

Why does the Earth not fall into the sun? Is it because Earth has angular momentum? or is it because the Earth has orbital momentum?

Homework Statement Light from the sun reaches Earth in 8.3 min. How far is the Earth from the sun? The velocity of light is 3 × 10^8 m/s. Answer in units of m. Homework EquationsThe Attempt at a Solution 8.3 min = 498 sec 3e8 x 498 = 1.494e11 m

From the north pole, how high is the sun @ midnight on the summer solstice ? Thanks

I know that the sun is a gas, but like the earth, no matter how hot the core, the enormous weight would turn it to a solid. So the suns core is a solid and would it spin on an axis? Or just randomly?

Dear PF Forum, I know that this question is purely speculative. And I should have googled it, but... In James Bond film, "Day Another Day", we saw that the villain, portrayed by Toby Stephens tries (and I might say, succeeds) to tranfer energy from the sun to some spot on earth, whether it can...

I know this is speculation but, if the inner solar system was permeated by a gas which could transmit sound waves (say for simplicity, similar to air), would we hear the Sun burning? And which kind of sound would it be? Which timbre and range of frequencies? Would it be unbearably loud? Or very...

I know that Earth orbits the sun because it has initial momentum and that prevents it from falling into the sun. But does moon that orbits the Earth also have initial momentum?

So, I heard the other day from someone online who claimed that if the sun would to suddenly disappear that the Earth would still travel in its regular path for 8 minutes before breaking off. The person claimed that because it takes light 8 minutes to reach Earth, and that since nothing can...

Homework Statement given: the speed at perihelion What is comets full energy? What is its distance from Sun at perihelion? How much time is the comet located inside Earth's orbit? Homework Equations parabolic orbit equation 3. The attempt at a solutin wrongly calculated l

These are questions I've made up to try and wrap my head around the topic, so the theory within the questions themselves might be flawed. 1. Homework Statement There are a number of metal sheets that are similar in every way except they each have slightly different masses. The temperature of...

How much smaller does the sun appear because of it's gravitational field ? This illustration shows EM waves being bent by the gravitational well of the sun. The light from the sun itself will also be bent by its gravitational well, making the sun appear smaller , ( and have barrel...

How can I prove to my 9 year old daughter that the moon is closer to Earth than the sun? At the moment, she has read it in books and this information has the same status as unicorns and fairy princesses!

I understand that white objects 'reflect' all frequencies of visible light, and black objects 'absorb' all frequencies of visible light. But I thought that 'reflecting' light means that the electrons in the atoms are caused to oscillate, and 'absorbing' means the electrons in the atoms are not...

Homework Statement There is no given data.the instruction ask to write ab essay about this topic.what will be find in the center? Homework EquationsThe Attempt at a Solution I read about sun.in the core there is fusion.neutrinos...etc.but i don't have a full idea.thanks for your helps.

which stage of the sun consists neutron star/stars

I’ve read that the light we can see coming from the sun originates from the suns photosphere which can be modeled as a black body emitter with a temperature of 5760 K. If I use Wien’s displacement law with this temperature to find out where the peak wavelength is: Peak = (2.8977*10^-3)/5760 =...

1. Asking because the answer I got seems too simple...a planet of mass m moves in an elliptical orbit about the sun. The minimum and maximum distances of the planet from the sun are called the perihelion and aphelion respectively. If the speed of the planet at p is vp, what is its speed at a...

The sun radiates its energy in all directions by emitting photons. As the photons travel as electromagnetic waves it reaches the earth. The photons collide with atoms and molecules in the atmosphere due the collision the energy of photons are emitted as heat. The atmosphere is thus heated and it...

Hi guys, I'm currently doing a little project an I need to calculate the speed of a satellite around the sun! I'm currently trying with the Earth, but i have some problem. When I'm using this formula : (2*Pi*a*Sqrt(1-e2))/T(1±e) I get an answer in km/s which seams pretty good. (29,75 km/s) But...

So I am working on making a simulation that shows the habitable zone of our solar system from now until our sun reaches the end of it's red giant phase. The sun will die when it is 10 billion years old and will reach the end of the red giant stage at 5 billion years. I know the habitable zone...

My question is, given that the Sun is composed almost entirely of just hydrogen and helium, why is the spectrum from it continuous and not an emission line spectrum? This applies to other stars as well. There are other elements of course present in the Sun, but they are present in very small...

Hello! These problems of mine are due in the morning. I'm not sure whether or not I will be able to figure them out in time, but I do need to understand the process in order to prepare for my finals. So any help would be much appreciated! Thank you. 1. Homework Statement A comet is in an...

Homework Statement The Earth's distance from the sun varies from 1.471 x 108 km to 1.521 x 108 km during the year. Determine the difference in (a) the potential energy, (b) the earth's kinetic energy, and (c) the total energy between these extreme points. Take the sun to be at rest. Homework...

I've recently been told by my mentor that the source for all energy is the Sun, which makes sense if were talking about chemical energy in photosynthesis, solar energy, etc. However, if we think about a meteorite which is due to hit the earth, surely we cannot say it got its energy from the Sun...

Hi! I have a question regarding the radiation coming from the sun. It might seem stupid to some people but I would really like to know how this works. When you see images of the sun's rays reaching the Earth for example on this image from wikipedia (see attached image). The rays are almost...

1. (a) What is the distance modulus of the Sun? (b) What is the Sun’s absolute magnitude?2. I found the distance modulous using 5log(4.84E-6/10) to be -31.6. I feel like I need the apparent magnitude to get the absolute, my teacher is very vague about what we are given to use. Is there a way...

Hi pf, I'm fairly new to QM so this may seem like a trivial question. As I understand it, an electron (or any small particle) does not have a definitive position in space until it is observed which causes the quantum wave like nature of the particle to disappear (collapse of the wave function)...

So I don't feel as freaked out as I did before reading the Tips sticky about making sure every bit of science is plausible. I would like to try and keep it believable for the immersion though. http://gizmodo.com/could-the-sun-be-extinguished-by-a-bucket-of-water-just-1669914928 It all started...

Homework Statement So, if the Earth stopped moving(supposing Earth's orbit is a circle) how much time would it have to pass before it hit the Sun? Homework Equations I've tried with Kepler, and Newton's derivations of Kepler's 3th law The Attempt at a Solution Well I'm pretty sure you need to...

Ok, we had a discussion in class: If we build solar panels all over the Earth's surface we can collect a good amount of energy. If we use this energy to power el-cars where does the energy end up? The energy law states that no energy can be lost from a system.

Imagine a stream of photons moving from the sun to the Earth (A, B, C, D, E, F, G, etc.). Now imagine 2 different men measuring the speed of the photons, and (somehow) recording which photon is hitting them. They are in the same position, but one is traveling 1/2 the speed of light (relative...

Let's say an alien race developed a powerful enough weapon to destroy** a star the size of our sun. How long would it take for humans on the surface of Earth or perhaps on the surface of another planet/moon in the solar system to feel the effects of this process? **"Destroy" is obviously...

Hi guys, so I know the sun is losing mass because it is radiating energy away. This leads me to wonder about some things - I have been trying to figure out what the mass of the sun was ~4.5 billion years ago (current age of the sun). Also I am interested in knowing what the mass will be ~6.5...

Got this problem on a standardized test Suppose scientists wanted to land a probe ON the Sun. The probe is being launched from the Earth. What direction should they aim launch the probe if they are launching it from the Earth? 1) Directly towards the sun 2) Directly away from the Sun — obv...

I know that the schwarzschild radius is proportional to the mass. But in case of black holes the mass remains the same only the size and density changes. So does the schwarzschild radius stay same when it is the sun and when it becomes a black hole?

Hello, here is the question I have to answer; I am aware that the gravitational energy of one layer of thickness dr is dU=-\frac{GM(r)dm}{r} and that ultimately I will have to integrate this over all radii but I am unclear about the expression for \rho_{center}. The only thing that springs to...

Homework Statement Nuclear fusion reactions at the center of the sun produce gamma - ray photons with energies of about 1 MeV (10^6 eV). By contrast, what we see emanating from the sun's surface are visible light photons with wavelengths of about 500nm. A simple model that explains this...

I'm rather new here so please forgive me if this is answered somewhere else, but I was unable to find it while searching around. For some calculations I'm looking to perform I need to know the geocentric equatorial coordinates of the sun on a given date. However, the only place I know they...

if the sun disappears, the Earth would go dark and life would end ... it would also go out of orbit but how soon? immediately? even the light takes 8 minutes to reach earth, as they are so far away... if the whole mass of sun disappeared suddenly... would Earth go out of orbit...

Hello! I'm not entirely sure this is very "scientific", but I have an idea that I would like some feedback on. I remember reading an article related to radioactive decay varying with the rotation and distance from the sun on Phys.org a few years back (http://phys.org/news202456660.html) and was...

Why the Earth is rotating around the sun? I know the centripetal force is required for the rotation of Earth around the sun. But initially there is required some force on Earth to rotate around the sun.

Light from the sun can be dispersed into its spectrum of colours. But when we look around us, and at the sun, it appears yellow. Then shouldn't it only be emitting the yellow part of the spectrum? We also use 'white light' sources when diffracting light through double slits, but then I couldn't...

I've read previous threads that the color of our sun from outer space is white, but on Earth it is yellow because oxygen and nitrogen scatter the blue light. First, I am wondering if this is accurate. Second, if this is true, why do we see stars in the night sky as white? I would think the...

I had this question given in my class A spectral line from iron (mass 55.934 amu) atoms in the sun is measured as 637.4 nm. It's width is measured to be 0.053 nm. Calculate the temperature of the sun?Now I done this using a formulae I was given but it yielded an answer no where near 5778KAbove...

I have tools that are made of metal and very reflective and shiny. If shiny objects reflect light waves, how is it that my tools get too hot to touch if I leave them in the sun (in the summer months)? Are the tools absorbing other forms of EM radiation?

Hello everyone. In my computational physics class, I am supposed to use numerical method to solve for equations of motion of the Earth and moon orbiting the sun, at which I place the origin of my coordinate system. However, I have a physics related question. Before I pose the query, allow me to...

Homework Statement A planet P orbiting the Sun S is acted upon by a force F= -(mu*r)/r3 (itex won't work here for some reason :S ) per unit mass where \mu is a positive constant and r is the vector \stackrel{\rightarrow}{SP} If the orbit of the planet is a circle of radius a, show that the...