On 01/12/2011 08:25 PM, David Jonsson wrote: > On Thu, Jan 13, 2011 at 12:00 AM, Mauro Lacy <ma...@lacy.com.ar > <mailto:ma...@lacy.com.ar>> wrote: > > On 01/12/2011 07:38 PM, David Jonsson wrote: > > I have derived an effect which differs from Newton/Kepler orbits but > > with the wrong sign apparently increasing the problem even more. > > > > I would be glad if someone could check the calculations before I > take > > them further. It would also be nice to calculate on some real > example. > > > > > > http://djk.se/Dark%20matter%20problem%20approached%20with%20classical%20physics,%20local%20rotation%20increases%20the%20centrifugal%20force%20away%20from%20the%20galaxy%20core.pdf > > I'll take a look later and comment back. > > > > How big is the anomalous acceleration at our solar system? > > If you're talking about the "anomalous" acceleration of the solar > system > around the milky way, you can calculate it using the centripetal > acceleration formula. I've calculated it in the past. If the Sun is > rotating around the galaxy at 220 km/s, and the distance to the center > of the Milky Way is ~ 26000 light years, and assuming we're > orbiting the > galaxy in a circle(which sounds like a good approximation) the Sun > must > be subjected to a centripetal acceleration ac = v^2/r ~= 2 x > 10^-10 m/s^2 > > > Right, and how big is the mass of the galaxy inside the orbit of the > solar system. I also need that to determine the error.
200 billion suns seems to be good estimate of the visible matter in the galaxy. From http://hypertextbook.com/facts/2000/AlinaVayntrub.shtml Considering dark matter, total mass could be 9 or 10 times that number. Let's calculate the acceleration produced by 200 million suns. This is doomed to fail because, as we know, galaxies don't obey Newton's gravitational law, but just to have an idea: a= Fg/msun = G msun*2*10^11/(26000 * 9.4607305e+15)^2 = 4.3882998825*10^-10 m/s^2 Which is two times the centripetal acceleration... if we suppose that the central bulge contains half the visible mass, the standard calculation will coincide with the observed values for our Sun. But it will fail for stars farther from the center, which are also moving at 250 km/s. In the wikipedia entry https://secure.wikimedia.org/wikipedia/en/wiki/Milky_Way you can see the expected vs. observed galactic rotation curves https://secure.wikimedia.org/wikipedia/en/wiki/File:Rotation_curve_%28Milky_Way%29.JPG And they inf fact coincide in the case of our Sun. Anyways, any effect smaller than, let's say, 2*10^-11 m/s^2, can be safely ignored. Regards, Mauro > > I calculated the anomalous effect from my paper and the acceleration > was on the order of 10^-26. Apparently too weak and in the wrong > direction, or a mistaken calculation. > > > > You might be interested in a thread in physics forums called "solar > system motions" (http://www.physicsforums.com/showthread.php?t=383916) > where I discuss the subject with some members. The thread called > "Alternative theories being tested by Gravity probe B " > (http://www.physicsforums.com/showthread.php?t=104694) from which the > previous thread was split off, is interesting also. > > > Hopefully I can check later. > > Regards, > David >
