Sun Definition and 996 Threads

Homework Statement This is for my Optics class: Given the radius of our planet, its temperature, and the distance to the Sun, estimate the temperature of the Sun (hint: use the Stephan-Boltzmann law). Homework Equations Radius of Earth \widetilde{=} 6,378.1 km Temperature of the...

Newton's Third Law of Motion: III. For every action there is an equal and opposite reaction. Photons in the sun on average travel outward, electrons and ions on average recoil inwards? Does Newton's third law come into play here? Thank you for help with my confusion.

Say a god got mad and could and did turn off the nuclear fires in our sun. About how long till Earth freezes? We read that it takes an incredibly long to for the average photon produced in near the center of the sun until the time it scatters for the last time and leaves the sun, does that...

In the energy producing region of the sun there is a large radial flux of high energy photons. Does this outward flux polarize the plasma and give rise to a electric field in this inner region? What is an order of magnitude estimate of this field? As the sun rotates this field gives rise to a...

Homework Statement The Milky Way galaxy (including the sun) rotates about its center with a period of 200 million years. The sun is approx. 2 X 10^20m from the center of the galaxy. What is: A) The radial acceleration of the sun? B) What is the net gravitational force on the Sun due to other...

Homework Statement The sun emits 3x1032J of energy every day. Assume it emits only yellow light (6x10-7m wavelength. a. What is the energy of each photon of yellow light? b. How many photons does the sun emit every day? Homework Equations E = hf The Attempt at a Solution So I think...

1) What keeps the Earth orbiting around the Sun? I know that gravity gives the force of the Earth towards the center of the Sun but what about the tangential force? What gives the Earth the tangential force? 2) What force makes the Earth spin?

So is there? :) ... Is there anything (radiation waves, particles, what not...) That Sun absorbs more than it emits? I guess it absorbs visible light of stars behind it, but it emits a ton of more. But is that the case with all EM frequencies? What about gamma rays or any other background...

Homework Statement the problem asks to find the distance from the sun to a planet. the only information the question gives the the orbital period of 27 years and asks for the answer in km. Homework Equations c= (2)(pi)(r) The Attempt at a Solution assuming the planet revolves...

Homework Statement The Earth travels around the sun in a circle of radius 150 million km and does a complete cycle in about 365 days. Find its speed. Homework Equations v= d/t The Attempt at a Solution d = 1000m/1km x 150,000,000km = 1.5 x 10^11m There are 31,536,000 seconds in 1year. v =...

I'm trying to show that for certain combinations of altitude and inclination there will be periods of the year where a satellite has eclipse-free orbits. Using a satellite-centered celestial coordinate system, in which the orbit plane is the equator and the direction of Earth is fixed along the...

I can't understand why the sun moves across the ecliptic :( I've been searching for hours and I've found nothing more than "because of the Earth's revolution around the sun", so I'm assuming this is extremely obvious - but I can't understand it. I understand why the declination angle of the...

Could there be objects between Mercury and the Sun? Like, say, asteroids?

The major conclusion: “A link between the Sun, cosmic rays, aerosols, and liquid-water clouds appears to exist on a global scale…” http://docs.google.com/gview?a=v&q=cache:k3yiHsNVc1cJ:www.wzforum.de/forum2/file.php%3F0,file%3D11877 keep in mind that solar modulation of clouds of even 2-3...

Homework Statement The sun is powered by fusion, with four protons fusing together to form a helium nucleus (two of the protons turn into neutrons) and, in the process, releasing a large amount of thermal energy. The process happens in several steps, not all at once. In one step, two protons...

This website gives a break down of the ten most abundant elements from spectrum analysis of the sun http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961112a.html" Presumably this result is only valid for the surface/near surface of the sun. If there were any heavier elements present...

Magnetic Field of the Sun will Flip I believe some time in November if I am not mistaken. It happens about once every 11 years. I am currently monitoring sites like: http://www.swpc.noaa.gov/SWN/sw_dials.html http://www.srl.caltech.edu/ACE/ASC/DATA/level3/summaries.html To monitor the...

In class today, we calculated that the amount of gravity between the sun and the Earth is 180. This is far greater than the amount of gravity beteen the Earth and the moon. So why does the moon affect the tides rather than the sun. My take: the sun is much farther and has a broader pull...

Does anyone know a good way to figure out where the sun is going to be around NYC on a specific day, throughout the day? I need to draw a diagram. I found a handy sun schedule on the U.S. Naval Observatory Astronomical Applications Department website, but I need more specific info than that...

Homework Statement In about 5 billion years, at the end of its lifetime, our sun will end up as a white dwarf, having about the same mass as it does now, but reduced to about 15,000 km in diameter.What will be its density at that stage? g/cm^3 Homework Equations D=m/v 4/3(3.14)r^3...

In 1916 Schwarzschild wrote down his famous metric to solve (or re-solve using a polar coordinate system) the precession of the perihelion of Mercury. The curvature of spacetime described by the Metric is for any non-rotating spherically symmetric mass. ds^2 = -(1-\frac{2M}{r})dt^2 +...

Reading about Velikovsky's pseudoscience, I wondered what the values of the Earth and sun's electric potential really are?

If a ship was traveling from afar toward our sun at 99.9999... C and skimmed the outer shell of the sun and continued on, would it burn up? From inside the ship, the trip through the shell might take a billionth or trillionth of a second, hardly enough time for the interior of the ship to heat...

I recall the non uniform distribution of magnetic fields is the reason sun spots occur. Why are sun spots more predominant about the equator as well?

Would this be valid for all other planets as well?

How long after the Sun becomes a white dwarf will it be until it becomes a black dwarf?

Just a quick question Are the planets totally locked in there orbits forever or do they slowly get drawn in closer to the sun?either by the sun's gravitational pull or simply by the sun expanding? Thanks in advance for any replys mike

By just knowing the clues like the force of attraction between two masses and angular momentum conservation principle , linear momentum conservation principle and geometry..can we derive the trajectory of the Earth around the sun is ellipse..if so please tell me your ideas..

The use of gravity-assist flybys of planets are well known for interplanetary missions. My question: can a Sun flyby be used to gain orbital energy relative to the Galactic center for interstellar missions? I assume one must first attain solar escape velocity by other means, since bound...

This might sound like an unoriginal question but what is gravity? Why does the Earth and the sun and other planets have gravity? Does everything have gravity? What causes gravity? Thanks ahead of time :smile:

Okay, I know that sun won't become BH (Black Hole) , and I know about Chandrasekhar limit and Tolman-Oppenheimer-Volkoff limit, etc. But my question is different. We know, M = m × √(1-v^2/c^2 ) . where m is rest mass. ( Don't know much latex, sorry :frown: ) So now we do know the rest mass...

I read in a paper the following passage: "We take the sun to subtend a linear angle of 32 arc-minutes. The solid angle is derived as \Omega=\pi sin^{2}16'=6.8x10^{-5} sr" I don't understand how the formula to go from linear angle to solid angle is just found by taking the area treating...

I had a friend who told me that there is a distance between the Earth and the Sun which the components of gravity add to zero. Is this true? If so, does this mean that something could get stuck there in that spot?

I'm doing physics of uniform circular motion, while I'm working out this equation It occurred to me , is it possible to find out how many rotations of Earth around the sun until it hits the sun. By the way I'm at a very NOOB level lol but seriously? *thinks of possible equation* :( not...

Hi all. Is the explanation for the fact that it is hotter at equator than other places at the Earth that the intensity of the Suns waves are greater at equator, since the number of beams per area is larger (since they are not scattered that much because of the lack of curvature)? I hope...

Hi, This might sound like a simple question, but it's not for me. I'm standing at the Tropic of Cancer - what would be the declination of the Sun on the Spring equinox. I believe it should be zero degrees, but my brother says it's 23.5 degrees. Can anybody shed light? Thanks in advance...

Homework Statement Using the table that follows, justify dividing the interior of the Sun into two separate functional layers (as regards energy production) and describe the average properties of those two layers.http://img26.imageshack.us/img26/8356/er3z.jpg Homework Equations R/R0...

Could anyone give me a figure (in joules/kilo joules) for this? Wikipedia says (on it's gravitational binding energy page) that the gravitational binding energy of a star is equal to about two times it's internal thermal energy. I looked for "internal thermal energy" and could not find...

Homework Statement Hi, A spinning shiny red-appearing planet at 130 billion km from the sun, has a diameter of 1700km. Estimate temperature of planet using simple heat balance equation. Estimate also the temperature obtained by Wien displacement law. Homework Equations I've been...

what is the percentage of heavy element (heavier than helium) of the sun? (not the photospheric composition)

I am after a reference or an explanation as to how the Voyager 2 spacecraft was used to determine the semi major axis (largest diameter) of the orbits of both Uranus and Neptune? These measurements were performed at Jet Propulsion Laboratory (JPL), NASA, during the Voyager 2 encounter with...

Homework Statement A planet moves in an elliptical orbit around the sun. The mass of the sun is M_s. The minimum and maximum distances of the planet from the sun are R_1 and R_2 , respectively. Using Kepler's 3rd law and Newton's law of universal gravitation, find the period of...

Homework Statement Two math students erect a sun shade on the beach. The shade is 1.5 m tall, 2 m wide, and makes an angle of 60° with the ground. What is the area of shade that the students have to sit in at 12 noon (that is, what is the projection of the shade onto the ground)? (Assume the...

Homework Statement Two math students erect a sun shade on the beach. The shade is 1.5 m tall, 2 m wide, and makes an angle of 60° with the ground. What is the area of shade that the students have to sit in at 12 noon (that is, what is the projection of the shade onto the ground)? (Assume the...

as we know "energy can neither be created nor destroyed it can be transferred from one form to another " . so the energy we receive from sun is dissipated here & some amount goes back . so the sun has more energy which gives energy out . so from where does this sun energy goes ??

Homework Statement Mars travels around the Sun in 1.88 (Earth) years, in an approximately circular orbit with a radius of 2.28 x 10^8 km Determine a) the orbital speed of Mars (relative to the Sun) b) the mass of the Sun Homework Equations acceleration centripetal = 4(pi^2)(r) /...

Hi everybody, I apologize if this has been asked already - I searched for a similar topic to no avail. My question regards something touched upon briefly in Olaf Stapledon's book Star Maker. Stapledon writes of interstellar travel being acheived by detaching a planet from a solar system and...

By "Is the sun anchored" I am referring to its place relative to the planets. I am pretty sure the answer is yes, as the planets also exert a gravitational force upon the sun (Newton's third law). This would cause the sun to "move" somewhat, no matter how small the force exerted. Then again...

A few weeks ago I saw a web page (I believe it was at NASA) that allowed you to enter a date and see Earth's distance to the sun on that date. I searched but can't find the site again, does anyone know where I can find this page?

Homework Statement The Sun rotates about its own axis once every 26.0 days. Its mass is m_sun = 2.0E30 kg and radius is r_sun = 7.0E8 m. Assume that the Sun is a solid sphere with uniform density. Astrophysicists predict that the Sun will collapse into a white dwarf in some billions of...