![]() |
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
![]()
The Anomalous Acceleration of Pioneer 10 toward the sun of
about 10^-8cm/sec^2 at various distances r from the sun can be associated with the fact that the velocity of the spacecraft is greater than the orbital velocity the spacecraft would have in a circular orbit at the same distance. A rationale for this coincidence is given below. The speed of the craft,now 12km/sec according to Pioneer home page was about 36.67km/sec as it passed Jupiter while 29km per sec relative to the sun when it was on earth orbiting the sun. If the spacecraft was in orbit around the sun at a distance r from the sun it would have an orbital velocity of v from GM/r^2=v^2/r So its orbital velocity at a distance r can be compared to its actual velocity v*_r compared to v_r. The hypothesis is proposed that the mass of objects is proportional to the total number of protons and neutrons in the object and to the transverse speed of the object wrt its attractive center eg the center of the earth for objects on the earth or in orbit around the earth, and the sun, for planets and other objects like the spacecraft beyond the earth's orbit. The Pioneer 10 spacecraft is moving almost completely radially away from the sun such that the sine of the angle between its trajectory and a radial line to the sun is very small eg .001. The spacecraft is also free to rotate. According to this hypothesis there would be change in the attraction of the spacecraft to the sun proportional to the difference between (GM/r)^1/2 and v*_r. If r=10^12 then ((6.67)(10^-11)(1.99)(10^30)/(10^12))^1/2=3.66(10^3.5)=11.57km/se c about and the speed of the craft was probably more. The attractive mass of an object on the earth directed to the center of the earth is assumed to be due to electrostatic dipole inside protons and neutrons of length 10^-18 meters so that (6.67)(10^-11) times [(1.67)(10^-27)]^2 = (9)(10^9)(es)^2 if s=(.9)(10-18) is the gravitational force between two protons one meter apart represented as the force between two electrostatic dipoles one meter part and colinearly and attractively oriented. And so the gravitational force between the sun and the earth could be written as the force between radially oriented dipoles: GmM/R^2 = 9(10^9)mM[6.02)(10^26)]^2 times kK times s*S* times (2.56) times 10-38 divided by R^2 where the dipoles are es* and eS* and e=1.6(10^-19)Coul.;this implies kKs*S*= (.0079)10^(-61-11+38) = 10^-36 approximatelySince the Sun is .75H+.25He so that 1.75kg of Sun contains 6.02 times 10^26 molecules each of which contains on average 1.75 protons+neutrons so 1kg of the gaseous Sun contains 6.02 times 10^26 protons+neutrons in a volume that is larger of course than that of 1 kg of a solid planet; but 1kg of any planet or the Sun contains the same number of protons+neutrons. There are about 2(10^30) kg in the Sun. Hence the Sun contains 6.02 times 10^26 times M or 12 times 10^56 and the Earth contains 6.02 times 10^26 times m or 3.59 times 10^51 unit dipoles in the Earth. The total dipoles a 1.2(10^57)k(s)RS* and 3.59(10^51)K(S)Rs*. Hence . Now RkS* and RKs* are the magnitudes of the dipoles associated with the Sun and planet respectively where R varies from around 1.5(10^11)meters 10^10 to 10^13 meters. But we also know that the Earth's dipoles cannot be much larger than atomic nuclei about 10^-15meters =RKs* that Ks*=10^-26 which implies kS*=10^-10 and also RkS*= 10^(-10+11) so the dipoles on the Sun are 10 meters in length or the amount of charge in each dipole is more than e=^-19 etc. We assume, following the Wilson Bartlett relation between angular momentum and gravity, that dipoles in protons and neutrons on planets that produce their attraction to the sun is due to the orbital speed of the planets and so a part of the planet, like the spacecraft, when moving apart from the planet at a different speed will have its dipoles change and so its attractive mass will change. see http://www.bestweb.net/~sansbury |
#2
|
|||
|
|||
![]()
On Sun, 23 Nov 2003 18:01:41 -0500, "ralph sansbury"
wrote: The Anomalous Acceleration of Pioneer 10 toward the sun of about 10^-8cm/sec^2 at various distances r from the sun can be associated with the fact that the velocity of the spacecraft is greater than the orbital velocity the spacecraft would have in a circular orbit at the same distance. A rationale for this coincidence is given below. The speed of the craft,now 12km/sec according to Pioneer home page was about 36.67km/sec as it passed Jupiter while 29km per sec relative to the sun when it was on earth orbiting the sun. If the spacecraft was in orbit around the sun at a distance r from the sun it would have an orbital velocity of v from GM/r^2=v^2/r So its orbital velocity at a distance r can be compared to its actual velocity v*_r compared to v_r. The hypothesis is proposed that the mass of objects is proportional to the total number of protons and neutrons in the object and to the transverse speed of the object wrt its attractive center eg the center of the earth for objects on the earth or in orbit around the earth, and the sun, for planets and other objects like the spacecraft beyond the earth's orbit. The Pioneer 10 spacecraft is moving almost completely radially away from the sun such that the sine of the angle between its trajectory and a radial line to the sun is very small eg .001. The spacecraft is also free to rotate. According to this hypothesis there would be change in the attraction of the spacecraft to the sun proportional to the difference between (GM/r)^1/2 and v*_r. If r=10^12 then ((6.67)(10^-11)(1.99)(10^30)/(10^12))^1/2=3.66(10^3.5)=11.57km/se c about and the speed of the craft was probably more. The attractive mass of an object on the earth directed to the center of the earth is assumed to be due to electrostatic dipole inside protons and neutrons of length 10^-18 meters so that (6.67)(10^-11) times [(1.67)(10^-27)]^2 = (9)(10^9)(es)^2 if s=(.9)(10-18) is the gravitational force between two protons one meter apart represented as the force between two electrostatic dipoles one meter part and colinearly and attractively oriented. And so the gravitational force between the sun and the earth could be written as the force between radially oriented dipoles: GmM/R^2 = 9(10^9)mM[6.02)(10^26)]^2 times kK times s*S* times (2.56) times 10-38 divided by R^2 where the dipoles are es* and eS* and e=1.6(10^-19)Coul.;this implies kKs*S*= (.0079)10^(-61-11+38) = 10^-36 approximatelySince the Sun is .75H+.25He so that 1.75kg of Sun contains 6.02 times 10^26 molecules each of which contains on average 1.75 protons+neutrons so 1kg of the gaseous Sun contains 6.02 times 10^26 protons+neutrons in a volume that is larger of course than that of 1 kg of a solid planet; but 1kg of any planet or the Sun contains the same number of protons+neutrons. There are about 2(10^30) kg in the Sun. Hence the Sun contains 6.02 times 10^26 times M or 12 times 10^56 and the Earth contains 6.02 times 10^26 times m or 3.59 times 10^51 unit dipoles in the Earth. The total dipoles a 1.2(10^57)k(s)RS* and 3.59(10^51)K(S)Rs*. Hence . Now RkS* and RKs* are the magnitudes of the dipoles associated with the Sun and planet respectively where R varies from around 1.5(10^11)meters 10^10 to 10^13 meters. But we also know that the Earth's dipoles cannot be much larger than atomic nuclei about 10^-15meters =RKs* that Ks*=10^-26 which implies kS*=10^-10 and also RkS*= 10^(-10+11) so the dipoles on the Sun are 10 meters in length or the amount of charge in each dipole is more than e=^-19 etc. We assume, following the Wilson Bartlett relation between angular momentum and gravity, that dipoles in protons and neutrons on planets that produce their attraction to the sun is due to the orbital speed of the planets and so a part of the planet, like the spacecraft, when moving apart from the planet at a different speed will have its dipoles change and so its attractive mass will change. see http://www.bestweb.net/~sansbury Apparently, the accepted explanation for the anomalous acceleration of Pioneers 10 and 11 is that they're experiencing a larger gas and dust density in the Kyper belt than was expected. |
#3
|
|||
|
|||
![]()
In message , Igor
writes On Sun, 23 Nov 2003 18:01:41 -0500, "ralph sansbury" wrote: The Anomalous Acceleration of Pioneer 10 toward the sun of about 10^-8cm/sec^2 at various distances r from the sun can be associated with the fact that the velocity of the spacecraft is greater than the orbital velocity the spacecraft would have in a circular orbit at the same distance. A rationale for this coincidence is given below. Apparently, the accepted explanation for the anomalous acceleration of Pioneers 10 and 11 is that they're experiencing a larger gas and dust density in the Kyper belt than was expected. Interesting. Do you have a reference for that? I'd be surprised, because the acceleration has been almost constant since about 15AU (inside the orbit of Uranus) and if anything there is _less_ dust than expected in the Kuiper belt.. Personally, I think it's looking more and more likely that Ned Wright is correct and they hadn't modelled thermal emission from the RTGs correctly. I haven't seen any evidence of an anomaly on Cassini. -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
#4
|
|||
|
|||
![]()
On Mon, 24 Nov 2003 00:03:07 +0000, Jonathan Silverlight
wrote: In message , Igor writes On Sun, 23 Nov 2003 18:01:41 -0500, "ralph sansbury" wrote: The Anomalous Acceleration of Pioneer 10 toward the sun of about 10^-8cm/sec^2 at various distances r from the sun can be associated with the fact that the velocity of the spacecraft is greater than the orbital velocity the spacecraft would have in a circular orbit at the same distance. A rationale for this coincidence is given below. Apparently, the accepted explanation for the anomalous acceleration of Pioneers 10 and 11 is that they're experiencing a larger gas and dust density in the Kyper belt than was expected. Interesting. Do you have a reference for that? I'd be surprised, because the acceleration has been almost constant since about 15AU (inside the orbit of Uranus) and if anything there is _less_ dust than expected in the Kuiper belt.. Personally, I think it's looking more and more likely that Ned Wright is correct and they hadn't modelled thermal emission from the RTGs correctly. I haven't seen any evidence of an anomaly on Cassini. Check out this link: http://www.newtonphysics.on.ca/Anoma...eleration.html |
#5
|
|||
|
|||
![]()
In message , Igor
writes On Mon, 24 Nov 2003 00:03:07 +0000, Jonathan Silverlight wrote: In message , Igor writes Apparently, the accepted explanation for the anomalous acceleration of Pioneers 10 and 11 is that they're experiencing a larger gas and dust density in the Kyper belt than was expected. Interesting. Do you have a reference for that? I'd be surprised, because the acceleration has been almost constant since about 15AU (inside the orbit of Uranus) and if anything there is _less_ dust than expected in the Kuiper belt.. Personally, I think it's looking more and more likely that Ned Wright is correct and they hadn't modelled thermal emission from the RTGs correctly. I haven't seen any evidence of an anomaly on Cassini. Check out this link: http://www.newtonphysics.on.ca/Anoma...eleration.html Very interesting! It's somehow satisfying that the explanation is conventional, not due to some boring property of the spacecraft, and gives new information. Presumably the reason Cassini hasn't seen an acceleration is that it's more than 20 x as massive. One thing does occur to me. Paul Marmet rather fancifully suggests that the Pioneers will gather dust as they move. It seems to me that the dust particles will actually be moving at very high speed relative to the spacecraft and will vaporise. More to the point, that means they will impart their kinetic energy to the spacecraft, which scales as V^2, not V. -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
#6
|
|||
|
|||
![]()
In article ,
Igor writes: Check out this link: http://www.newtonphysics.on.ca/Anoma...eleration.html It's an interesting idea. While I didn't check the calculations in detail, the method looks correct, and it certainly appears to produce an upper limit for the density of the Kuiper Belt of 1.4E-19 g cm^-3. What I wonder is how reasonable that density is. It seems awfully high to me. At a "normal" gas to dust ratio of 100, that's about 8E6 hydrogen atoms per cubic centimeter. I suppose one could argue that the gas is depleted, or maybe this density is reasonable. Anybody able to comment? One clear mistake in the web page is the assertion that the IRAS data show the Kuiper Belt. Dust in the KB is far too cold to have been seen by IRAS. The IRAS data sample the Zodiacal cloud roughly 1 AU from the Sun. (Of course the data average over a range of distances.) That's why the data are depicted as blue in the figu they represent the 12 micron observations. COBE produced much better data on the Zodiacal cloud, leading to detailed models. However, not even the COBE data detect dust at the KB distance from the Sun. The expected temperature is roughly 75 K at 30 AU. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
#7
|
|||
|
|||
![]() Jonathan Silverlight writes: In message , Igor writes Check out this link: http://www.newtonphysics.on.ca/Anoma...eleration.html Very interesting! It's somehow satisfying that the explanation is conventional, not due to some boring property of the spacecraft, and gives new information. Presumably the reason Cassini hasn't seen an acceleration is that it's more than 20 x as massive. One thing does occur to me. Paul Marmet rather fancifully suggests that the Pioneers will gather dust as they move. It seems to me that the dust particles will actually be moving at very high speed relative to the spacecraft and will vaporise. More to the point, that means they will impart their kinetic energy to the spacecraft, which scales as V^2, not Marmet's explanation is unconvincing. It depends entirely on the density of dust in the outer solar system, which according to Marmet: This amount of dust in the outer region of the solar system appears quite reasonable remembering that the daily amount of dust falling on Earth is reported as many tons of dust grains per day. which is a completely fallacious argument. The number of "tons" of dust falling on the earth has nothing to do with the dust conditions in the outer solar system, because (a) one must normalize the captured "tons" by the cross sectional area of the earth; and (b) the conditions are different in the outer solar system. In particular, the dust density drops of precipitously beyond Jupiter. It is straightforward to show that the net acceleration due to dust is: a_dust = -2 (A/M) n V^2 m where A/M is the area to mass ratio of the body, n is the dust density, V is the body velocity, and m is the mean dust mass. This conservatively assumes elastic scattering. It is likely that the dust will be captured, in which case a_dust will be half the value quoted above. Dust properties in the outer solar system have been measured, in some cases by quantitative dust instruments on Pioneers 10 and 11 themselves (Landgraf et al 2002; Gurnett et al 1997). The there is a continuous density distribution. According to the above equation, the acceleration is heavily weighted to large dust particles, but these are extremely rare. The net densities are of order 2 x 10^{-17} cm^{-3}, with dust masses ~0.1 ug, leaving the net acceleration due to dust to be safely less than a few times 10^{-12} cm s^{-2}, far less than the quoted anomalous acceleration. Craig References D. A. Gurnett, J. A. Ansher, W. S. Kurth, and L. J. Granroth 1997, Geophys. Res. Lett., 24, 3125 M. Landgraf, J.-C. Liou, H. A. Zook, and E. Gr\"un 2002, Astrophys. J., 123, 2857 -- -------------------------------------------------------------------------- Craig B. Markwardt, Ph.D. EMAIL: Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response -------------------------------------------------------------------------- |
#8
|
|||
|
|||
![]()
In message , Craig Markwardt
writes Jonathan Silverlight writes: In message , Igor writes Check out this link: http://www.newtonphysics.on.ca/Anoma...eleration.html Very interesting! It's somehow satisfying that the explanation is conventional, not due to some boring property of the spacecraft, and gives new information. Presumably the reason Cassini hasn't seen an acceleration is that it's more than 20 x as massive. One thing does occur to me. Paul Marmet rather fancifully suggests that the Pioneers will gather dust as they move. It seems to me that the dust particles will actually be moving at very high speed relative to the spacecraft and will vaporise. More to the point, that means they will impart their kinetic energy to the spacecraft, which scales as V^2, not Marmet's explanation is unconvincing. It depends entirely on the density of dust in the outer solar system, which according to Marmet: This amount of dust in the outer region of the solar system appears quite reasonable remembering that the daily amount of dust falling on Earth is reported as many tons of dust grains per day. which is a completely fallacious argument. The number of "tons" of dust falling on the earth has nothing to do with the dust conditions in the outer solar system, because (a) one must normalize the captured "tons" by the cross sectional area of the earth; and (b) the conditions are different in the outer solar system. In particular, the dust density drops of precipitously beyond Jupiter. It is straightforward to show that the net acceleration due to dust is: a_dust = -2 (A/M) n V^2 m where A/M is the area to mass ratio of the body, n is the dust density, V is the body velocity, and m is the mean dust mass. This conservatively assumes elastic scattering. It is likely that the dust will be captured, in which case a_dust will be half the value quoted above. I don't understand how the dust can be captured. Isn't it likely to be hitting with a relative velocity of the order of Pioneer's own speed (12 km/sec)? But is the question still open, or is anisotropic thermal emission still the best candidate to explain the Pioneer effect? Marmet doesn't mention the conventional explanations. -- Rabbit arithmetic - 1 plus 1 equals 10 Remove spam and invalid from address to reply. |
#9
|
|||
|
|||
![]() Jonathan Silverlight writes: I don't understand how the dust can be captured. Isn't it likely to be hitting with a relative velocity of the order of Pioneer's own speed (12 km/sec)? To be honest, I'm not sure. That's why I assumed the worst case of elastic collisions, which maximize the momentum transfer to the spacecraft. Since the dust particles are fluffy bodies, it is likely that they will not elastically scatter, and so the momentum transfer will be less. But is the question still open, or is anisotropic thermal emission still the best candidate to explain the Pioneer effect? Marmet doesn't mention the conventional explanations. I've looked into this a little more. From my analysis, there is some evidence for a change in the acceleration over time. This is almost enough to be consistent with the decrease in the amount of power consumption in the Pioneer 10 equipment compartment. I think it is quite possible there could be anisotropic emission from this compartment, or via some other, similar means, which accounts for the acceleration. Craig -- -------------------------------------------------------------------------- Craig B. Markwardt, Ph.D. EMAIL: Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response -------------------------------------------------------------------------- |
#10
|
|||
|
|||
![]()
Craig Markwardt replied to Jonathan Silverlight:
But is the question still open, or is anisotropic thermal emission still the best candidate to explain the Pioneer effect? Marmet doesn't mention the conventional explanations. I've looked into this a little more. From my analysis, there is some evidence for a change in the acceleration over time. This is almost enough to be consistent with the decrease in the amount of power consumption in the Pioneer 10 equipment compartment. I think it is quite possible there could be anisotropic emission from this compartment, or via some other, similar means, which accounts for the acceleration. Craig, I posted this on February 22, 2002, here in sci.astro, in reply to Bruce Sterling Woodcock: Presently some 2000W of RTG heat must be dissipated, so it would seem that would be enough. But the problem is the RTGs are located at the ends of the booms, and they only see the antenna "edge on", subtending an angle of about 1.5% of 4 steradians. That means at most 30W of power could be impacting it. Moreover, every RTG is not a spherical black body, but rather has fins that are "edge on" to the antenna, which means only 2.5% of the surface area of the RTG is actually facing the antenna. The RTG mechanism doesn't provide enough power to explain the anomalous acceleration. Looking at photographs of the spacecraft leads me to wonder whether the analysis you quote is correct. First off, you said "an angle of about 1.5% of 4 steradians". That was probably intended to be "4 pi steradians", meaning the total sphere. By eyeball estimate, I'd say that the antenna and other parts of the spacecraft sunward of the RTGs subtend a solid angle of about 5% of a sphere, rather than 1.5%. I estimate that 20% of the RTGs are visible to the sunward parts of the spacecraft, rather than 2.5%. Those are pretty big differences. Perhaps my estimates are that far off, or perhaps someone fouled up the analysis. Take a look at some photos of Pioneer, and see if you don't agree that the figures you give seem way too low. Maybe it still isn't enough to cause the anomaly. But it looks like a very good possibility. Bruce replied, in part: The RTG's have fins on them that are "edge-on" to the antenna. The actual surface area that faces the antenna is much smaller because of it. And I replied to Bruce: Yes, I can see that. It is why I estimate that only 20% of the RTG surface area is visible to the back side of the antenna dish and other parts of the spacecraft sunward of the RTGs, rather than the approximately 45% that would be visible if they were plain cylinders. Any comments? -- Jeff, in Minneapolis Subtract 1 from my e-mail address above for my real address. .. |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Pioneer Saturn (aka Pioneer 11) Encounter Trajectory - Question. | Ian R | History | 4 | December 4th 03 10:26 PM |
Pioneer 10 Update - December 3, 2003 | Ron Baalke | History | 0 | December 3rd 03 04:49 PM |
"Pioneer anomalous acceleration" and Cassini | Jonathan Silverlight | Astronomy Misc | 49 | November 18th 03 07:37 PM |