tsolkas Posted April 12, 2006 Posted April 12, 2006 ''TSOLKAS'S PROBLEM'' FOUR QUESTIONS ON THE ADVANCE OF MERCURY'S PERIHELION QUESTIONS 1. At what distance (in Km) does the Sun's center of mass lie from the center of mass of our solar system? 2. What kind of movement does the Sun perform around the center of mass of our solar system (circular, elliptical, etc) and what are the particulars of this orbit? 3. How much time (period, in years) does the Sun need to make a complete revolution around the center of mass of our solar system? 4. To what extent (expressed in ° degrees) does the Sun's movement (around the center of mass of our solar system) contribute to the advance of Mercury's perihelion? What answers have the various universities, physicists, etc, given to the above questions? Sincerely, Christos A. Tsolkas
lqg Posted April 12, 2006 Posted April 12, 2006 i might not be an astronomer but isn't the centre of our solar system is the sun itself? (regarding your first question).
insane_alien Posted April 12, 2006 Posted April 12, 2006 No the barycenter is offset from the center of mass of the sun. everything in the solar system orbits the barycenter including the sun itself. can't actually remember how far off it is but i think its just inside the sun.
Cloud Posted April 12, 2006 Posted April 12, 2006 i might not be an astronomer but isn't the centre of our solar system is the sun itself? (regarding your first question). So that would be (0, 0, 0) 2) I think its called differential rotation and this is measured by observing sunspots. (I don't know if Galileo went blind because of this:confused: ) In regard to the ACTUAL question (didnt think things through) - I'm guessing circular (its a large body - this is how it would travel). 3) Strangely, its about 28 - 31 (hence differential) earth days. Thats for the rotation. I don't know about a revolution (Is there one?) 4) whoaah there - don't know that. ??? somebody*fill in the blanks*
m4rc Posted April 12, 2006 Posted April 12, 2006 The way to determine the answers to your question is to do a simulation applying the laws of gravity to a many body system. I have found the results of one of these simulations on http://www.sunorbit.net/ . Instead of just taking this data from the internet, if I were you I would either find or write a program to calculate the effect of the planets gravity on the sun. However from the results listed on the site I refered mentions that: 1)The distance between the sun and the centre of mass of the solar system is about 3 million Km (a few solar diameters). 2) The motion is not circular and described in the reference. 3) The period of this motion is 22 years. 4) The reference doesn't mention any results on Mercury's orbit. I suggest that you find out how to simulate the effect of gravity on a many body system. Only then will you have your answer. There are several simulations available if you google gravity and simulation.
Sisyphus Posted April 12, 2006 Posted April 12, 2006 Yes, the sun moves, because of Newton's third law. The sun can't exert gravitational pull on the planets without them exerting just as much pull on the sun. Determining its motion is not terribly difficult. You just have to find the center of gravity of all the other bodies in the system, excluding the sun, and observe its motion relative to the sun. You can treat this center of gravity as one body, at the center and with mass equal to their total mass. Then, all you have is a two body system. Two bodies orbit one another in similar orbits about their common center, with radii inversely proportional to their masses. Thus, if you have the motion of the C.O.G. for the rest of the system relative to the sun, you just divide the line between the two centers inversely proportional to their masses, and the point of division is the immobile center of gravity about which they both orbit in identical shapes. However, none of this really matters. You can just assume a reference frame in which the sun is stationary (which, of course, is the easy and sensible thing to do), and it doesn't really change anything important. m4rc, just so you know, the site you linked to is ridiculous. The cause for energy production in the sun? Physics "didn't know" about this? Crank!
Cloud Posted April 12, 2006 Posted April 12, 2006 However' date=' none of this really matters. You can just assume a reference frame in which the sun is stationary (which, of course, is the easy and sensible thing to do), and it doesn't really change anything important![/quote'] So we agree with the (0, 0, 0) tsolkas - you're homework's done. We have reached a conclusion that the sun is the centre of the solar system and your questions are therefore void.
JohnB Posted May 20, 2006 Posted May 20, 2006 Determining its motion is not terribly difficult. You just have to find the center of gravity of all the other bodies in the system, excluding the sun, and observe its motion relative to the sun. You can treat this center of gravity as one body, at the center and with mass equal to their total mass. Then, all you have is a two body system. Two bodies orbit one another in similar orbits about their common center, with radii inversely proportional to their masses. Thus, if you have the motion of the C.O.G. for the rest of the system relative to the sun, you just divide the line between the two centers inversely proportional to their masses, and the point of division is the immobile center of gravity about which they both orbit in identical shapes. Mate, how does this work? I'm not trying to be argumentative, I just can't visualise the explanation properly. Simply put, wouldn't the COG of all the other bodies be moving independently of the sun or the COG of the entire system? This COG would be moving in a complicated pattern from outside the orbit of Jupiter to clear across the system. I just can't see how this could be used as part of a two body system. Wouldn't it make the calculations more difficult rather than simpler? m4rc, just so you know, the site you linked to is ridiculous. The cause for energy production in the sun? Physics "didn't know" about this? Crank! I know what you're getting at, however the author of the site is simply reworking Maxwell's work from the 1800s. He also makes a seemingly valid point re the energy released by gravitational distortion. The forces involved are indeed huge and can't be disregarded. (I'm still reading up on this topic, but it does seem interesting.)
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