The sun Definition and 634 Threads

I want to find the rotational energy of the sun. Erot=1/2*I*ω2 m=1.9891*10^30 kg r=6.955*10^5 km When I am using the formula for a sphere's moment of inertia: I=2/5*m*r2 I'm getting 3.848671797*1047 km*m2 Can i find the moment of inertia in another way? the moment of inertia needs...

Hello, One or two years ago I had a mathematics lecture where one part of it was using basic formulae, a pendulum and the distance to the centre of the Earth to find out what the distance to the sun was. Recently, I came across a question which asked me to figure out the distance to the...

My friend told me that the sun is going to get smaller and smaller every year because it's getting used up? I've read that the power output is 4 x 10^26 Watts. How can i figure out how much mass it's losing a second? because then I will be able to find how long the sun will be able to shine on...

Homework Statement Earth orbits around the sun at roughly 1.5x1011 m. Mass of Earth is 6x1024 kg. Mass of sun is 1.98892x1030 kg. There is a point between the sun and the Earth at which the gravitational force by the sun equals that of Earth and the forces cancel each other out. How far is...

The Earth orbits the sun in an approximately circular orbit of radius 1.496 * 10^11 m (about 93 million miles) in a period of 365 days. Use these data to determine the mass of the sun. Solution: F = (Ms)(Me)(G)/r^2 I have two unknowns... F and Ms... please give suggestions because I...

This is one of the questions on a small exercise but I don't understand it. I thought that the Earth is in orbit because the mass of the Earth and the Sun combine perfectly such that the orbital velocity is exactly the same as the pull of the sun so the Earth is forever falling towards it. If...

In a thread that was just open and almost immediately closed: https://www.physicsforums.com/showthread.php?t=546278 there was a link to a possible crackpot site, but one part of the discussion said simply that the sun (the whole solar system) moves through space. A graphic demonstrating this...

http://www.youtube.com/watch?v=Ex283trHBgE&feature=player_embedded I am in a debate with someone who is defending this guy vehemently on another forum. Does anyone know of any link debunking what this guy is saying? The “adherent” of this point of view is quite vehement and I’d just love to...

Sunlight takes eight minutes to reach Earth. Meanwhile the sun and Earth have moved/rotated. Suppose that the sun emitted two types of light, the 8-minute light and a spooky “zero-time light”. Where in the sky would we see/measure the second spooky sun - the real position of the sun? The...

Homework Statement Find the gravitational force of the sun on Mercury M_sun = 1.98892 x10^30 kg M_mercury = 3.3022 x10^23 kg Distance of sun and mercury = R = 6.863 x10^10 G = 6.67 x10^-11 Homework Equations FG = GMsunMmercury/R^2 The Attempt at a Solution I simply plugged...

How to simulate planets orbit curve around the sun ? Hi I'm about to write a java program where I wish to simulate planets orbit curve around the sun, so that I can set the speed of a planet and mass of planet and sun and simulate the curves around the sun (just basic simulations). I only...

I was astonished recently to find myself able to look directly into the sun without experiencing impairment of vision as a result. I have done so many times since but there are occasions when the light is too bright. What I saw when I looked at the sun was quite awe inspiring. The outer rim...

Calculating the equation of time and the declination of the sun Hi, I'm trying to calculate the equation of time and the declination of the sun in the prettiest way possible: https://gist.github.com/1278755" But right now I'm getting some unexpected values: 1) Failure...

Do the sentence "when the sun is shining then it is hot" is a logic sentence ?

Homework Statement "Determine a surface temperature value for the Sun from the angular diameter of the Sun and the solar constant." Homework Equations L=4π(R^2)σT^4 The Attempt at a Solution At this point my only stumbling block is I don't understand the relationship between the solar...

I am trying to understand an example in my Modern Physics textbook (Example 3.1, page 5 in thishttp://phy240.ahepl.org/Chp3-QT-of-Light-Serway.pdf" or pg 69 using the book numbering) I don't understand why the average earth-sun distance is being used in the conservation of energy equation...

Homework Statement Is it possible to use the heat of the sun to heat a liquid (arbitrary liquid) to a temperature that is hotter than the sun, say 5 times hotter? Homework Equations Concepts in thermal equilibrium The Attempt at a Solution My answer is no since you can't get more...

I tried calculating the mass of the core of the sun but keep coming up with a number that exceeds the entire mass of the sun. I used http://en.wikipedia.org/wiki/Sun" facts on the sun. It says the core of the sun extends from its center to .2 to .25 times it's radius. I used the number .225 as...

Hi! When it comes to physics, I'm a total layperson (so, please, be kind ;-)), I actually study English, but recently my interest in physics has been growing more and more. So, yesterday I started watching the first of Feynman's Cornell University lectures. And that led me to the question: why...

In wikipedia I've read that the Sun's surface temperature is about 5700K. The emission spectrum graph can be seen there: http://en.wikipedia.org/wiki/File:EffectiveTemperature_300dpi_e.png. I don't understand why the irradiance (or intensity I guess) of the Sun is greater than the one of a...

Hi, I am currently studying the internal structure of the sun and I was wondering if there exists scientific information regarding the pressure distribution along a hypothetical line from the core to the, let´s say, convection zone. You can find frequently in the internet that the pressure in...

I've looked into optics and the biology of the eye, and I know that, although the fovea is an area with our highest visual acuity, light is still focused on the retina around the fovea even when we're not looking directly at something. Clearly it is not safe to look direct at the sun, but people...

Is the reason behind the vibrating the movement of electrons from a stable to a excited state? My quest for knowledge began with this question..."How exactly does light transform into heat--for instance, when sunlight warms up a brick wall? I understand that electrons in the atoms in the wall...

Hi, new here. This came up briefly elsewhere and we didn't have the cerebral fire power to get very far with it. Consider very, very long wavelength photons, (or conversely, very very low energy photons) produced inside the sun. Wavelengths we are looking at are in the range of 1 light...

why density of core of the sun is changing ? please give me brief explain with calculation

No, not right now. But when it cools down, billions and billions of years from now?

While making a projection of the sun on a paper with a Newton telescope, I’m able to see a white ball or to make burning holes in paper. My idea however is to be able to see something more spectacular , like sunspots or protuberances. Does someone has an ideas how to do this practically...

No doubt the core, photosphere, and corona are all integral features of the sun. The solar wind and heliosheath come under similar consideration. Currently it appears certain solar features at several scales are undergoing dynamic changes which look something like weakening. Ulysses has...

Does all (i.e. 100%) of the energy generated in the Sun's core via nuclear fusion eventually escape out into space (as photons, neutrinos, ... and umm solar wind?), or is some energy lost to internal processes? Surely the photons must lose energy as they take their long, indirect path from the...

I'm not sure if this is in the right forum. If the Sun disappeared, would the Earth's velocity change? Since the space-time fabric would 'spring' back into it's normal position, the effect of gravity on the Earth would dissipate? Thus, resulting in the Earth being thrown out of it's orbit?

Hydrogen atoms are in ionised state in the Sun? So the electrons are in a separate gas state? If, yes, than what is the main properties of that gas: temperature, partial pressure, velocity distribution, etc. Can somebody give me a good reference or answers?

Hello, I would like to ask why if the Earth rotate around the Sun in circle orbit, it must have an kinetic energy equal to negative half of potential energy it has at anytime rotating round the sun, which Ek = -Ep/2 ! If this situation cannot be achieved, our Earth will move in a new ellipse...

Hello! could you help me with this? I´m from biology field and have some difficulties with the following calculation: I want to estimate how much mor UV is coming from a mercury short arc lamp of a fluorescence microscop compared with the sun UV, so that I use the right eye protection for...

Homework Statement [a] find the toal power radiated into space by the sun, assuming it to be a perfect emitter at T=5500 K. The Sun's radius is 7.0x10^8 m. [b] From this determine the power per unit area arriving at the earth, 1.5x10^11 m away. The Attempt at a SolutionHey guys! Sorry for...

Homework Statement If a scuba diver fills his lungs to full capasity of 5.5 L when 8.0 m below the surface, to what volume would his lungs expand if he quickly rose to the surface? Homework EquationsP=pg(H) The Attempt at a SolutionHeyguys! :) I know that P=pgh but I have volume...

Homework Statement temp = 6000k what is the power radiated by the sun per megacycle bandwidth at a wavelength of 2cm? Radius of sun = 7 x 10 10 cmHomework Equations i was asked to use this equation energy density u = ω2kT dω / (π2c3) NOTE: π is pi. not n The Attempt at a Solution but how do...

One of the proposals for harnessing solar energy is to put solar panels in space. Either orbiting the Earth, or stationed on the moon, light waves could be converted into microwaves that pass through the atmosphere without losing any energy, then on to electricity on the ground. What I'm...

A solar model is used to calculate the expected temperature and density at all depths within the Sun. These results are then used to calculate the expected fusion rate within the Sun. We have confidence that the model is correct because it agrees with the observed characteristics of the Sun...

Homework Statement The Earth is approximately 1.5x10^8 km from the sun. what is the Earth's angular momentum about the center of the sun. Note the mass of the Earth is 5.97x10^24. Homework Equations The Attempt at a Solution I got the answer, but my question is, when finding the...

I found this hilarious. This guy makes a pretty amusing argument for why we should destroy the Sun. http://destroythesun.com/" Surely, we should set aside our differences, band together and fight this threat.

I've had a good search through the archives and haven't found an answer to this question. Many apologies if this is old ground. . . Having read the threads on the Pioneer Anomaly a quick question to which I'm sure there is very simple answer (I just don't know what it is !): When...

Last semester in my astronomy class, we tried to find an equation that would fit the path of the sun based on measurements we took, but we realized that due to the change in the tilt of the earth, it wouldn't be a simple sine or cosine graph, and we dropped the subject. I was wondering if there...

Hi there Problem is: if hydrostatic equilibrium were violated by .01% so that 0.01% of the gravitational force were imbalanced by the pressure gradient, estimate how long it would take the sun to change its radius by 10%. My attempts at solving problem: My feeling is that the...

I'm writing an article in a plastic modeling magazine talking about scale weight. Plastic models come in many scales, i.e. 1/72 or 1/48, etc., so my article talks about what weight a model would be if it was also scaled properly for weight. For instance, a 2000 lb car, at 1/72 scale, would...

Gday all, I was just wondering if we would experience a (very small) centrifugal force due to the Earth's rotation around the sun or not. I don't think there would be because the Earth and everything on it is in a state of free fall around the sun, but I have been told there would be a...

Here we have got a very long rod (100 million km length or so) built/placed on the lunar surface (near equator) and directed towards the Sun (imagine that Moon is in synchronous rotation with Sun and therefore that point (where this rod is built) is always looking at the Sun). The distance...

Will the gas planets become solid? Since they are no longer receiving heat from the Sun?

Hi so I am doing a presenation, on the indirect search for the neutralino from the sun at amanda In short: neutralinos are graviationally captured and settle int he sun.. they decay to produce neutrinos.. we detect the neutrinos at the amanda detector through muon productionSo what I am...

I've been reading this evening that the Sun went Dark last night for just about a min. Is this true or are people just blowing smoke?

The history of our understanding of the sun is a very rich area. Ancients believed the sun was a god while we now know the sun is an enormous body of fusion. What I would like to discuss is how the scientists thought the sun worked after the development of the basics of thermodynamics but...