|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
Search: calculator for long numbers.
(formerly)" dlzc1.cox@net wrote in message news:IDy1b.8763$Qy4.1287@fed1read05... Dear George Dishman: "George Dishman" wrote in message ... (formerly)" dlzc1.cox@net wrote in message news:GLc1b.6297$Qy4.6003@fed1read05... ... Actually the behaviour is consistent with Dark Matter distributed near the periphery of the Solar System, adding to the mass inside the Solar System. Do you have a reference for that or can you show how it leads to a constant acceleration? I can show very little (since I care little for DM). The anomolous behaviours of spiral galaxies is pretty much evenly distributed based on distance, achieving approximately identical radial velocity regardless of distance. I think you mean constant orbital speed regardless of radius. This would indicate a consantly increasing DM concentration, For a point mass M, v(r) = sqrt(GM/r). For uniform density (what I thought you meant by "pretty much evenly distributed based on distance") v(r) = sqrt(4/3 pi G p) / r where p is the density. To get v(r) constant you need the density of the DM to fall as the square of the radius. However, clearly the orbits of the planets do not behave that way. constantly variable G (ala MOND to some extent), or some other thing. If, in the case of Pioneer, the distribution is essentially apparently a step change in G, then the distribution of DM, if that is the cause, would be just "inside" the radius where the anomolous acceleration occurs. As far as they can tell, the anomalous acceleration is constant over the whole range where they can measure it. The lower limit is simply where it gets swamped by the solar radiation pressure. Assuming G is constant, then M_ss must increase (where M_ss is all the known mass within that radius and DM). It is also consistent with them hitting slower moving gases too. Surely the density needed is far higher than the observational limits. I would think so, but this is one of the flavors of "reasons" I have read. A decreasing mass density with increasing differential velocity would do the trick. Not unreasonable, unless there was no change in the anomolous acceleration across the orbit of planets (presumably swept by the planet) or the "shadow" of planets (where the mass outflow was gravitationally bound or at least deflected) There is no change at all anywhere. Solar wind, in some sense. Slower, cooler, expanding more and more slowly, but less dense due to, well the usual culprits. The Solar wind is thousands of times less than radiation pressure and entirely negligible throughout the range. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Challenger/Columbia, here is your chance to gain a new convert! | John Maxson | Space Shuttle | 38 | September 5th 03 07:48 PM |
3rd European Workshop on Exo/Astrobiology - Mars: The Search For Life | Ron Baalke | Astronomy Misc | 0 | August 6th 03 06:16 PM |
Study: Search For Life Could Include Planets, Stars Unlike Ours | Ron Baalke | Science | 0 | August 2nd 03 02:05 AM |
Study: Search for life could include planets, stars unlike ours (Forwarded) | Andrew Yee | Astronomy Misc | 0 | August 2nd 03 01:33 AM |
Interesting NPR story on Columbia debris search | Patty Winter | Space Shuttle | 1 | July 26th 03 12:54 AM |