The answer, of course, is no, planets do not orbit the sun in closed planar ellipses. So what? It is a fact that the planets orbit the sun with various planet-sun radii. The earth’s orbital speed is approximately 30 km/sec. Some astronomers use the distance between two points on the orbit trajectory to set a base line for triangulating the distance of stars. There is an interesting problem here as the sun is also in orbit, ostensibly around the galaxy center. A brief review of the sun’s speed with respect to the galaxy center indicates speeds from 220km/sec to 266ernetkm/sec. Check the many references on the internet. There may be claims of higher or much lower speeds of th sun, but the range stated seems to prevail. This being the case it appears undeniably that the trajectory of the planets with the same reference point as the sun, to wit, the galaxy center, are certainly not planar ellipses; the trajectories are forms of helices, although one can search the astronomical literature and would not discover such ‘planetary helical orbit’ claims. It seems most strange that planetary motion has been so inordinately separated from sun motion notwithstanding both motions have been known for some time. At a sun speed of 250 km/sec [an average of claimed speeds - more or less] the sun would travel 365days/yrx250km/secx24hrs/dayx3600sec/hrs or approximately 79x10^9 km/yr. to the sun motion. This assumes the 'ecliptic plane' is perpendicular to the sun's motion. A ½ year distance then is approximately (80x10^9)/2 km or approximately 40x10^9km. Using a planar ellipse model for ½ year in orbit produces 2AU or 2x1.5x10^8km or approximately 3x10^8km. Therefore the ratio of actual ½ year travel to the ½ year planar ellipse distance is (40x10^9)/(3x10^8) or 133. Astronomers using the planar ellipse model to determine the base line for triangulation results in a much distorted determination of the measured stellar distance. By a simple ∏/2 rotation from the planar ellipse model the base line for triangulation can be increased by a factor of approximately 133, otherwise the second ½ year point is actually 133x2AU projected away from the original point, hence the much distorted measurement of stellar distances from earth have resulted over the years. Comments anyone?
have you tried reading on the Mercury orbit? Google the "advancement of the Mercury perihelion", it will answer your claim about "helical orbits".
Parallax is useful for measuring distance to closer stars, stars that are orbiting the galaxy along with the Sun. It's not simple triangulation. It's done by comparing the angles between many stars over several years. Generally speaking, the way the direction to a star changes from one year to the next tells you something about how the velocity of that Star is different to the velocity of the Sun. The way the direction changes back and forth through the year tells you something about the distance to that star.
That's because the motion of the solar system through the galaxy or the motion of the galaxy through the Local group is irrelevant to the description of the motion of the planets relative to the Solar System's center of mass. Your entire "point" boils down to a half-assed embrace of absolute motion but your ignorance of the motion of the galaxy itself betrays your philosophy of absolute motion. In actual practice -- to the extent that it has been a cornerstone of physics since 1905 -- the Galilean principle that only relative motion matters is firmly rooted in the experimental record that no attempt to measure absolute motion has succeeded. Thus the discussion of what imaginary shape one would have if the orbit of a planet was present to experiment with is necessarily a function of as to what reference of position one in using. Relative to an inertial (not rotating) frame of reference built on either the center of the sun or the center of mass of the Solar System, the shape of all the orbits of the planets are close approximations to planar ellipses. Tach mentions Mercury because it has an anomaly which has long been used to cement the superiority of one theory of gravitation over another, but because all the planets pull on each other, this is only apparent after you subtract out the perturbations to the former theory's perfect ellipse caused by other planets. (No more abuse of color?)If I was a square, I'd be a gross, but nowadays, I am a cube. Post 1,728. (what about) \(\color{red} 12^3 = 1728\) (Both look red in preview)
Knowing his anti-mainstream tilt and given the fact that he's talking about "closed" orbits, I thought the best way to shut him down is to remind him about the fact that the orbits are , in fact, open and that they precess.
Pete, If one uses the same reference system for planets and sun then as the sun moves through space it drags the planets along with it. Certainly using the sun as the planet's reference frame the orbits are planar ellipses, but referencing the planet motion the same as the sun, that is the center of the galaxy around which the sun supposedly is in orbit, the planets necessarily are helical, assuming the ecliptic is perpendicular to the sun direction of motion. A technique use fr triangulation is to set the base line of the triangle along the line joining the two points on the earth orbit that are separated by 1/2 years motion which is believed to be 2AUortwo earth-sun radii (approximately). However, this procedure does not take into account the sun's motion. As the angle subtended by thesolutely correct that themotion of the stars is a meaasured parameter but if not mesured using the proper base line in triangulation, measurement results are ambigupous. One may triangulate using measurment points on opposite sides of the earth simultaneously, orlay use the 1/2 year orbital distance for triangulation lines from both points make an angle in fraction of degrees; using the actual base line distance increased 133 times the accuracy of distance measure, and star motion can be increased accordingly. In any event triangulation using basic trigonometry is used to determine distances of 'nearby' stars. Are you saying that the planetary motion with respect to the center of the galaxy, the same reference point from which the sun is in orbit, is not heleical?
Using the center of the galaxy as a common referecnce point for sun and planets, the planets trajectories are helical, whether this is anti-mainstram or not. Your mind is made up isn't it, cast in mainstream concrete as it appears to be?
Relative to the center of the galaxy from which the orbit of the sun is determined, the trajectories are helical. If yo wish to not use the same reference system for sun and plamnets go with it. I am not concerned with the moton of the galaxy her, I am cncerned with the same reference system for sun and planets, which I assume is the galaxy center. I don't argue with this. However, when the sun and planets are referenced from the same coordinate system, the galaxy center, the planetary motions are helical. I don't get it.
I am familiar with this planet's difference in trajectory, but in the projection of the orbit of mercury in the direction of sun motion is a squished helix.
Start by getting the motion around the Sun right. Once you do that you will get the motion wrt the center of the galaxy correct.
This is your assumption, and not a universal assumption. Therefore since the shape of the orbit depends on the reference of position, your initial post where you stated that the shape of the orbits is not elliptical, is not a statement of absolute truth. Indeed, the elliptical shape of the orbits was first deduced by Kepler, long before the existence of the galaxy was shown. At the time, the Sun was the only reasonable reference point for the solar system. Just as it is unreasonable for you to critique Kepler for not describing the shape relative to the arbitrary choice you made -- a standard that was unknown to him, so it is equally unreasonable for you to not admit the existence of other references of position, such as the center of mass of the Local Group or the frame where the cosmic microwave background has no dipole moment. But the most important reason to focus on the center of mass of the solar system (or the Sun) as the reference of position is that the dynamics of the solar system are largely self-contained. In this self-contained system the elliptical paths of the orbits told Newton something important about celestial motion -- that there was an inverse-square force law centered on the Sun. Thus to pick an arbitrary reference point, you obscure this important discovery. A gross = 144 = 12². A square = n². A square is also a dated term for someone who failed to appreciate the zeitgeist. A cube = n³. Second test of red text
Hi Geiskiesel, Your reply to me repeats the OP without addressing what I said. Firstly, please consider that in practice this method is useful only for close stars, which are orbiting the galaxy at close to the same speed as the Sun. No, it's not naive triangulation. You have to look at the change in angle over several years. When you do so, you can tell how much of the angle change is due to the Sun's motion (the linear component), and how much is due to the Earth's orbit around the Sun (the sinusoidal component).
If you opened any book on GR you would find that the projection is an ellipse precessing in its own plane.
