The sun Definition and 634 Threads

Someone I know recently stated according to General Relativity, the following statements are both correct: 1. The Sun rotates around the Earth. 2. The Earth rotates around the Sun. Is this true?

Homework Statement Mars's orbit has a diameter 1.52 times that of Earth's orbit. How long does it take Mars to orbit the Sun? in years. Homework Equations I tried using T^2=4(pi)^2r^3/GM I got 1.88years...but its wrong... The Attempt at a Solution

A surprisingly small number of photos submitted for a theme that is right smack in the middle of the summer months here in the northern hemisphere. Still, we have a good group of photos. Please choose a photo that best depicts the spirit of having fun in the sun. 1. matthyaouw 2...

Fun in the Sun This week's theme involves all the fun activities we do during the warm days of summer. Zz. Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're not sure...

Homework Statement Which of the following is a true statement concerning a comet passing near the sun? (Mass of comet and mass loss are negligible) 1. The momentum of the comet is nearly conserved because the interaction with the sun is similar to an elastic collision. 2. The momentum of...

I need to check a calculation for reasonableness. When I plug in the values for Earth and the Sun, I get a rough approximation of tidelock about 5.5 Gy after formation of the solar system. Is that anywhere close to the right answer?

If the sun is converting matter to energy it must be losing mass at roughly one Earth mass per 43 million years (calculated from the solar constant). How would the loss of solar mass affect the Earth's orbit?

How do scientists know that the Sun orbits the Milky Way? Is this something more ancient scientists knew or could have known hundreds of years ago?

Just sitting around BS'ing with a couple of friends this morning about the solar system and gravitational balance- and I began to wonder how long the Earth and its inhabitants would last if the sun suddenly quit emitting energy. How long would our atmosphere retain enough heat to keep us from...

that it would burn everying in a 90 mile radius, or something like that, is this correct? Would this be the same as if the equivelant amount of hydrogen atoms fused all at once together?

If the Earth orbits the sun how can astronauts fell no attraction to the sun in space. Even pluto which is 4500 million years away, still orbits the sun.

What time of the year is the Earth closest to the sun? Does this time vary?

I saw in a website that Einstein found the deflection angle of a ray grazing the sun through this relation alpha=4GM/c2r=1.74 arc sec but when i used this relation by giving values i didnt get this value 1.74...wats wrong..can anyone solve this ...

[SOLVED] luminosity of the sun What equation do you use to figure out the luminosity of the Sun if you are given the amount of energy the Earth receives from it?

What is the angular velocity of the sun? thanks

Hey, Does anyone know where to find a value for the radial velocity of the Sun wrt the Earth? I've tried googling, but it always gives the radial velocity wrt the LSR. Thanks muchly!

[SOLVED] Amount of Energy emitted from the sun to the earth Homework Statement The Sun's surface temperature is 6000 K. Assume that the radiation emitted from the Sun moves radially outward from the Sun and that no radiation is absorbed between the Sun and Earth. How much energy in the form...

I'm having trouble getting the answer to this homework question: How many Earths would fit into the Sun? can you guys help me in solving it, please? Thnak you

Some of my friends are arguing how gas giants were created far from the Sun, while the rocky planets were in the inner orbits. One of the ideas is at first they were all the same: gas giants, then the solar wind blew the outer layers of the inners and they became rocky. How do you think of this?

Dear all, Can only the outter planet form rings? If Saturn were moved very close to the Sun, would it be able to maintain its ring system? I personally don't think so due to the fact the high tmperatures would vaporise a lot of the ice in the ring system but I would like to everyone else's...

Hi, Homework Statement I was just wondering, because the Earth follows an elliptical path around the sun and the gravitational force of the sun on the Earth is towards the sun, would the work done on the Earth be considered positive or negative? Homework Equations The Attempt at a Solution...

Once again I have no idea what my physics professor is asking- I am not asking for direct answers necessarily but any help is much appreciated! http://www.physics.utah.edu/~cassiday/p1050/homework06.html

If we could move the Earth, how far away from the Sun would it need to be to maintain a temperature similar to what we have now when it becomes a red giant? How large would the Sun apear in the sky? Would the sky still be blue? Would everything have a red tint to it? I was...

Hi. I am curious about the following nuclear reaction: \nu_{e} + ^{71}_{31}Ga \rightarrow ^{71}_{32}Ge + e^{-}. Can anyone explain to me why this reaction has an energy threshold of approximatly 0.23 MeV? How does one calculate the minimum energy of the neutrino for this reaction to take...

http://www.wdc.rl.ac.uk/wdcc1/papers/nature.html It would be interesting to find out just what this doubling effects if anything. http://www.wdc.rl.ac.uk/wdcc1/papers/nature.html may be this. http://www.economist.com/world/displaystory.cfm?story_id=9071007 or this?

Homework Statement Derive the equation using Newton's Law of gravitation and the equation for circular motion. Homework Equations V = \sqrt{\stackrel{GM}{r}} Where G is the universal gravitational constant, M is the mass of the central body and r is the radius...

Homework Statement What is the acceleration due to gravity of the sun at the distance of the Earth's orbit? Homework Equations law of gravity = Gm/r^2 Sun's Mass: 1.99x10^30 kg, earth-sun distance: 150x10^6 km The Attempt at a Solution ((6.67*10^(-11)) * (1.99*10^30))/...

Is it conceivably possible that our orbit around the Sun is changing? Through unforeseen gravitational forces, Increases and decreases of mass, or the makeup of space itself, can the current way we measure time gradually get to the point where it's completely wrong?

I read a article describing the normality of the sun. It actually described that the sun is pouring the solar neutrino in less amount then predicted by the theory of particle physics. It is due because the sun is right now "boiled off" i.e. its rate of nuclear burning is decreased. If so then...

What is the capacitance of the sun? semms like a straigtforward question but I can't seem to find any information on what it is. I'm don't know if it has been measured, or if its even possible to measure, but I would have thought a body that big and active as the sun would have an ability to...

Hello, Here is my question: Just imagine the sun would stop shining, without exploding. It would just totally disappear without causing harm. How long would human race survive without the benefits of the sun? 10 minutes? 10 hours? 10 days? Could it stand the cold longer? How long would it...

I can "understand" the gravitational pull of the sun on the Earth and the Earth mass effect toward the moon, but what pull the sun? a neophyte.

A comet is in an elliptical orbit around the Sun. Its closest approach to the Sun is a distance of 4.5 1010 m (inside the orbit of Mercury), at which point its speed is 8.9 104 m/s. Its farthest distance from the Sun is far beyond the orbit of Pluto. What is its speed when it is 6 1012 m from...

Homework Statement The flux from the Sun above the Earth's atmosphere is about 1370 watts/m^2. This quantity is called the solar constant S and equals pi*f(sun). Use the angular radius of the sun as seen from the Eart to find pi*F , the surface flux of the sun. Homework Equations...

I am not an astronomer or astrophysicist but lately, I have been reading a lot of books to upgrade my knowledge in cosmology. I have encountered two issues that I am baffled about and wonder if anyone can help me throw some light on them (1) If the planets are parts of the sun or came from...

Homework Statement How does the temperature of the Earth change when the sun suddenly stop radiating?:confused: how will the temperature vary with time? Please help me solve this one. can we answer this one using models or simply through theories? can you explain how? Homework Equations...

I might already know the answer to this but i just need to make sure. Does a suns mass reflect its volume? I ask because... The formation of a star simply put is: a planet gathers mass there-by gathering gravity there-by igniting and becoming a star…it becomes a star with x amount of mass...

I was trying to come up with a solution to the timeline when hypothetically speaking the sun would stop shining ( or emitting radiation). Now, gravitational issues aside (the sun as a body still there), how long would it take for median temperature to drop beyond freezing point around the globe...

How do plants grow towards the sun? Thanks.

Homework Statement On October 15, 2001, a planet was discovered orbiting around the star HD68988. Its orbital distance was measured to be 10.5 million kilometers from the center of the star, and its orbital period was estimated at 6.3 days. Question A: What is the mass of HD68988? -- I...

Homework Statement How long does it take the Sun to melt a block of ice at 0°C with an area of 1.10 m2 and thickness 1.07 cm? Assume that the Sun's rays make an angle of 31.1° with the normal to the area, and that the emissivity of ice is 0.0400. Homework Equations Q/t = IeAcos(theta)...

Why does the sun appear to have such low surface gravity? Most would say the the nuclear reactions inside the sun continually pushes matter outward against the force of gravity, but this does not account for the slow fall of solar flares and speed of solar wind. According to the current...

Hi. I'm really not sure if I'm posting this in the right place. If not, I'm sorry. Anyway, here's the thing: I'm doing research for a fantasy novel I'm writing. I know virtually nothing about any kind of science, so I need help with the following question: if the sun were to rise in the west and...

I'm going nuts trying to figure this out... in textbooks and online, everything i read says that the moon and Earth have a much stronger gravitational force between them than the sun and the earth, and this is why the moon has greater effect on tides than the sun. They all say that this is...

How much does the moons mass contribute to the Earth's orbital distance and characteristics around the sun. If the mass of moon and the Earth were not joined At the hip or say the moon magically disappeared :rolleyes: would the Earth's orbit around the sun still be within the habitable zone...

this just appeared in the peer-review journal Physical Review Letters. I noticed the preprint of it on arxiv last year and thought it was pretty far out. Here is the revised October 2006 preprint: http://arxiv.org/abs/astro-ph/0610844 Shining light through the Sun Malcolm Fairbairn, Timur...

I have three questions. 1. Why are galaxies disk shaped and not spherical? 2. Theoretically speaking, if there were a hollow sphere at the exact center of the Earth and you were in it then what would you feel from a gravitational point of view? Would you hover and be able to bounce from...

Hi all, I was hoping for a little advice and some insight on these pictures I took. Here is the first (orig_small1.jpg): And the Second after I realized and waited for a break in the traffic (orig_small2.jpg): I was on the Skyway Bridge in the passenger seat driving from St. Pete...

Hello, I've got this problem: The sun converts 1.91exp19 kg of Hydrogen to Helium per year, given that the sun started out with 75% Hydrogen by mass, computer how long the sun would shine if it converts all it's Hydrogen to Helium. I computed the total energy of the sun as 3.81exp41...

during the sunrise and sunset, we find the sun reddish in color...why is it so...my view is that as the distance to Earth during these times is longer than mid-day, and applying doppler effect, as the sun nears the apparent wavelength decreases and so is the perceived color...is this approach...