Sun Definition and 1000 Threads

The Sun and Moon appear larger while near the horizon. The explanation I heard for this optical illusion is that when the Sun and Moon are near the horizon our brain(eyes) have something to reference their size to therefor making them appear larger. But which is their actual size? Is the size...

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?

Why is it said that light takes 8 minutes to reach Earth when light from sun is already present in the solar system , what is meant exactly by the statement ?

Homework Statement "Calculate the gravitational force between: A) The sun and the earth B)The moon and the earth" Homework Equations F= M/r2 The Attempt at a Solution A)The sun and the earth Earth: mass 5.97*10^24 kg Radius 6,380,000 meters Sun: mass 1.99*10^30 Radius...

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?

Homework Statement a planet is 2.00 a.u. when it is closest to the sun. its eccentricity is .5000. Find its period in years. Homework Equations The Attempt at a Solution i got this so far... don't know if it is right PD + AD = A -AD - PD = F <SUBTRACTING THESE TWO>...

[SOLVED] gravity fun Homework Statement 1. Calculate the speed of objects on the Earth's surface caused by the Earth's own rotation around its own axis. 2. Find the mass of the Earth using its time period of revolution of the moon around the earth. 3. Find the mass of the sun using the...

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.

I ran across some article that pointed to this research: http://www.omatumr.com/picpages/snexplo.html The theory states that Sun formed from accretion of supernova remnants back into/onto its core. Now, my scientific background is quite limited but this theory seems to me more realistic...

Obviously life on Earth must get energy from the Sun. But MOST of the Suns energy must be radiating out into space, pretty much "wasted" from our perspective. So, my question is, about how much energy do you figure the sun produces per second? What sort of things on Earth could be powered...

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

Hello All, Please excuse my ignorance. I have a number of questions about the sun. Space is cold, yes, very very cold, close to absolute Zero. I have heard the argument that it is solar radiation or through convection that the heat from the sun reaches us. However I still can't get my head...

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]Forces: acceleration with a sun yacht Homework Statement Sunjamming. A “sun yacht” is a spacecraft with a large sail that is pushed by sunlight. Although such a push is tiny in everyday circumstances, it can be large enough to send the spacecraft outward from the Sun on a...

[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!

I just learned the sun has an equatorial rotation rate of approximately 25 Earth days, and a polar rotation of approximately 31 days. Intuitively, by the laws of physics, it should be the other way around: longer at the equator and shorter at the poles? Also, if our solar system is within...

I have a question that I can't figure out. In the Sun, it takes several hundred thousand years for a photon released in the core to reach the surface. Use the speed of light and the radius of the sun to estimate the escape time for a photon from the center of the sun if there were no...

Hi, Is it posible for us to determine the velocity of our sun? The Hubble constant gives a referent for the exspansion of the universe but do we have any way of knowing if the point at the centre of the big bang was, (or is), stationary? Do we know in which direction the centre of our...

[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...

Problem: The Earth's orbit (assumed circular) around the sun is 1.5e11 m in radius, and it makes this orbit once a year. What is the centripetal acceleration of the earth? Equations: a = (v^2) / r T = (2*pi*r) / v My work: T = (2*pi*r) / v; 1 year = (365 days / 1 year)*(24 hours /...

Homework Statement How many Earth's would fit inside the sun? Homework Equations The Attempt at a Solution I found the volume of the sun and the Earth (Using the sphere volume formula) and devided the sun's volume by the Earth and got 10^6...I was wondering whether this is the...

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

Homework Statement To better comprehend the gravitational force between the Earth and the Sun, pretend gravity is turned off and the pull replaced by the tension in a steel cable joining them. How thick would such a cable need to be? You can estimate the diameter by knowing the tensile...

A long while ago I had this idea for a plot of a story. Now I'm not so sure my logic is right. If I were to place a (perfectly) mirrored parabolic dish out near Pluto, point it at the sun and put my (tiny point-like) spaceship at the focus, how big would the parabolic dish have to be to give...

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?

I am doing some research for a graphic novel I am building with a group that will take place on Gliese 581c/Gliese 581d and am trying to get as accurate information as possible about what the sky, light and plant life would look like in either of these environments. Could this be an accurate...

Why I can burn a paper with magnifying glass and sun? Isn't it something to do with the electromagnetic field (because light is itself electromagnetic field)?

This question was asked today in my physics examination. Sun Glasses do not have power. Why? I know that the main function of Sun Glasses is to reduce the intensity of light by polarisation. Therefore there no need for them to have power. Or is it something else.

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...

Homework Statement The gravitational attraction of the Sun and Moon on the Earth produces tides. The Sun's tidal effect is about half as great as the Moon's. The direct pull of the Sun on the Earth, however, is about 175 times that of the Moon. Why is it that the Moon causes larger tides...

I have no idea where this goes... But I have a question. Say if the sun was big enough to turn into a black hole, what will happen to the earth? Will it stay in the same orbital path or will it be suck in by the black hole? Thanks

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

More sample exam problems... 2) The mass of our sun is ~ 2 x 10^30 kg. The mass of a planet is 6 x 10^24 kg. If the distance between the center-of-mass of each is 100 x 10^11 m, what is the distance in meters from the center-of-mass of the sun to the center-of-mass of the Sun- Earth...

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...

Homework Statement A spacecraft is initially in a circular orbit of the sun at the Earth's orbital radius. It uses a single brief rocket thrust parallel to it's velocity to put it in a new orbit with aphelion distance equal to the radius of Jupiter's orbit. What is the ratio of the...

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...

does the fusion reaction in sun produce neutrons or neutrinos? i read websites of which one is saying neutron is produced but the other one says neutrino is produced..which one is correct..what other things would be produced when hydrogen fuses to produce helium in the core of sun?

does the fusion reaction in sun produce neutrons or neutrinos? i read websites of which one is saying neutron is produced but the other one says neutrino is produced..which one is correct..what other things would be produced when hydrogen fuses to produce helium in the core of sun?

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?

The ratio of the mass of the Earth to the mass of the moon is 84.5. Assume that the radius of the Earth is about 6578.0 km and that the distance between the center of the Earth and the moon is 385815.0 km. Determine the distance of the center of mass of the earth-moon system from the center of...