The sun Definition and 622 Threads

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 [FONT="Fixedsys"][SIZE="2"][SIZE="4"]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...

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...

We are studying Energy at school The book said that "All Energy on Earth can be traced back to the Sun" I know there is mechanical energy chemical energy electrical energy Are they talking about everything? I mean cars, fireplaces, ect...

helloooo new to this forum...and a total science noob who comes to you seeking knowledge... :rolleyes: Anyway - i recently saw the new danny boyle movie 'sunshine' - the story is about the sun dying and a rescue team who's on a mission to save the sun by reigniting it. My question...

I've been reading Kip Thorne's book "Black Holes and Time Warps" and was wondering about a couple of things. They're really basic questions that have been floating around in my head, but I can't ask any of my friends because none of them know anything about these topics, so...I came here...

No big rocky planets? Why are there no big rocky planets - all the big planets are gaseous. Did big rocky planets get smashed up and end up in the Kuiper belt?

Nature decides that instead of inverse square law for gravitational forces the law will be inverse cube law. In that case what among the following will be true? a) The force of gravity from the sun will be weaker b) The period of the planet will be proportional to the square of the distance...

Even though in optics experiments we assume that the sun rays are parallel, we can clearly see that the sunlight seems to diverge from the sun when coming through the clouds. Whats the reason of this discrepancy?

I've been hearing these talks that the sun will run out of hydrogen in 4.5 to 5 billion years from now. My question is, how did we arrive at this estimate. Is it based on the mass or something? It would be good if you can show me the mathematical calculations. --thanks.

The Earth is subject not only to the gravitational force of the moon but also to the gravitational pull of the sun. However, the earth is much farther away from the sun than it is from the moon. In fact, the center of the Earth is at an average distance of 1.5 x 10^11 m from the center of the...

a)calculate the mass of the sun from the radiuos of the Earth's orbit (1.5 x 10^11m), the Earth's period in its orbit, and the gravitational constant of G. Sohere we are given the speedof light, 3x10^8, and G as 6.673x10^-11 so i get that v=2pi x r / T and that r= ct how do i continue...

Whenever something interesting happens on the side of the sun that faces earth, is there any orbiting satellite that can simultaneously view the opposite side?