#21
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Hurt wrote: Sorry, clicked post accidentally. No probs, easily done. I have replaced some previously snipped context: Well George, the Pioneers are almost centered symmetrically above the ecliptic plane, so an object somewhere below the plane might be plausible. No, the majority of the anomaly would then be directed out of the plane. The anomalous acceleration is in the plane towards the Sun. They don't give any precise vector; they use words like away, towards, and radial towards the Sun. Page 18: ... "Over the years the data continually indicated that the largest systematic error in the acceleration residuals is a constant bias of a_P ~ 8+/-3)*10^-8 cm/s^2, directed toward the Sun (to within the beam-width of the Pioneers' antennae [73])." And...? That was the ~ (approximate) LARGEST error. That doesn't change the uncertainty of the magnitude variation. Once again: "No magnitude variation of aP with distance was found, within a sensitivity of s0 = 2×10-8 cm/s2 over a range of 40 to 60 AU." Perhaps I should have added some emphasis, the relevant part wasn't the uncertainty in magnitude but the statement regarding the direction. You said "They don't give any precise vector" but they do in fact say that the direction is within the beamwidth, or +/- 1.8 degrees of the line from the craft to the Sun. Think of what you were suggesting: ecliptic: ----P----------E--S--------- The dashes show the plane, P is Pioneer, E is Earth and S is the Sun. Your putative extra star would be somewhere off in this direction: | | V but the anomalous acceleration is in the plane to within 2 degrees. Note [73] indicates the beamwidth is 3.6 degrees. As What note [73] indicates is that they could not tell whether the force direction was towards the Sun or if the force direction was towards the Earth. Or somewhere else! A beamwidth of 3.6 degrees, at the probe, spreads a whole lot over a distance of over 60 AU. It is still a cone less than 4 degrees wide no matter how far away. PDF page 51: [73] We only measure Earth-spacecraft Doppler frequency and, as we will discuss in Sec. VIIIA, the down link antenna yields a conical beam of width 3.6 degrees at half-maximum power. Therefore, between Pioneer 10's past and present (May 2001) distances of 20 to 78 AU, the Earth-spacecraft line and Sun-spacecraft line are so close that one can not resolve whether the force direction is towards the Sun or if the force direction is towards the Earth. If we could have used a longer arc fit that started earlier and hence closer, we might have able to separate the Sun direction from the Earth direction. I said, there's a lot of information in the paper if you are serious, but that means reading the endnotes. Unfortunately I don't have enough useful time to read everything; and still, I'm doing pretty good. You are actually, there's lots of bits of information scattered through the document and even more in the dozens that came subsequently. I've been going through these of and on for 5 years and I haven't extracted it all. Page 34, commenting on the possibility of a correlation with the RTG radioactive decay: "Finally, we want to comment on the significance of radioactive decay for this mechanism. Even acknowledging the Interval jumps due to gas leaks (see below), we reported a one-day batch- sequential value (before systematics) for a_P, averaged over the entire 11.5 year interval, of a_P = (7.77+/-0.16)*10^-8 cm/s^2. From radioactive decay, the value of a_P should have decreased by 0.75 of these units over 11.5 years. This is 5 times the above variance, which is very large with batch sequential." Unless you're trying to tell me something indirectly I don't see what this has to do with our conversation. Maybe you're trying to baffle the masses? No, you were commenting that the uncertainty in the mean magnitude was about +/- 2 in these units from one part of the paper and I was pointing out that in another part you can find a figure of +/-0.16, an order of magnitude better. A numbger of data processing methods were used with different sample batches and so on, so you have to be careful about the details. "Hurt", gravity produces the same acceleration independent of mass. Read up on Galileo. Did I say anything about acceleration? I can qualify my statement. "... something that barely budges a small spacecraft won't [measurably OR significantly OR noticeably] move a planet." That is still wrong, it should be. ".. something that barely budges a small spacecraft will barely budge a planet by exactly the same amount." What is the angular acceleration of a planet, say Earth. Not to mention its instantaneous linear tangential acceleration. IT'S HUGE. Both very small, if the Earth were in a circular orbit both would be exactly zero. The _radial_ acceleration is larger, but why don't you calculate it as a simple excercise to get a feel for the numbers. Take that vector and add it to ~ 8*10^ -8 (that's a minus 8) cm/s^2 and you basically get that vector. I don't know if we could even measure such a small change over many years. Easily. They checked to see if a gravitational effect was a possible cause and the orbits of the planets would have shown changes that would be detectable in a few years. I can't remember the exact numbers Can you point out the section that says this please. Not immediately or I would have done so, I suspect it isn't in the main paper but a subsequent one so I'd have to trawl through to find it. George |
#22
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Perhaps I should have added some emphasis, the relevant part wasn't the uncertainty in magnitude but the statement regarding the direction. You said "They don't give any precise vector" but they do in fact say that the direction is within the beamwidth, or +/- 1.8 degrees of the line from the craft to the Sun. Think of what you were suggesting: ecliptic: ----P----------E--S--------- The dashes show the plane, P is Pioneer, E is Earth and S is the Sun. Your putative extra star would be somewhere off in this direction: | | V but the anomalous acceleration is in the plane to within 2 degrees. As soon as the vodka from the past few days wears off I'll try to give that paper another look. But this is a good discussion. What is the angular acceleration of a planet, say Earth. Not to mention its instantaneous linear tangential velocity. IT'S HUGE. Both very small, if the Earth were in a circular orbit both would be exactly zero. The _radial_ acceleration is larger, but why don't you calculate it as a simple excercise to get a feel for the numbers. I'm surprised no one nailed me on that gaff. Yeah I was about to try running those numbers before my time ran out. I'm using a limited use public computer. Hey Google, how about a spell checker for the news groups. Take that vector and add it to ~ 8*10^ -8 (that's a minus 8) cm/s^2 and you basically get that vector. I don't know if we could even measure such a small change over many years. Easily. Are just the tidal forces enough to mask such a small quantity? |
#23
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"Hurt" wrote in message ps.com... Perhaps I should have added some emphasis, the relevant part wasn't the uncertainty in magnitude but the statement regarding the direction. You said "They don't give any precise vector" but they do in fact say that the direction is within the beamwidth, or +/- 1.8 degrees of the line from the craft to the Sun. Think of what you were suggesting: ecliptic: ----P----------E--S--------- The dashes show the plane, P is Pioneer, E is Earth and S is the Sun. Your putative extra star would be somewhere off in this direction: | | V but the anomalous acceleration is in the plane to within 2 degrees. As soon as the vodka from the past few days wears off I'll try to give that paper another look. But this is a good discussion. OK. Try to work out what the effect would be bearing in mind your extra objects would influence not only the craft but the Sun and planets too, it is only the difference in accelerations that becomes measurable. The key factor is how any anomaly varies with the distance of the craft from the Sun. What is the angular acceleration of a planet, say Earth. Not to mention its instantaneous linear tangential velocity. IT'S HUGE. Both very small, if the Earth were in a circular orbit both would be exactly zero. The _radial_ acceleration is larger, but why don't you calculate it as a simple excercise to get a feel for the numbers. I'm surprised no one nailed me on that gaff. Yeah I was about to try running those numbers before my time ran out. I'm using a limited use public computer. Hey Google, how about a spell checker for the news groups. I suggest using a calculator and piece of paper before getting to the computer. The old ways still work ;-) Take that vector and add it to ~ 8*10^ -8 (that's a minus 8) cm/s^2 and you basically get that vector. I don't know if we could even measure such a small change over many years. Easily. Are just the tidal forces enough to mask such a small quantity? What "tidal forces"? It may be small but integrate over a couple of centuries of reasonable records of planetary motions and it mounts up, and since it is directly added to everything else, it can't be masked. George |
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OK. Try to work out what the effect would be bearing BTW, I'll workout when I get a membership to the Y or Gold's. |
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On 5 Jul 2006 18:12:40 -0700, "Hurt"
Gave us: OK. Try to work out what the effect would be bearing BTW, I'll workout when I get a membership to the Y or Gold's. Jeez... do you say ANYTHING that isn't utterly retarded? NO, ASSWIPE, there is no grand conspiracy to keep scientific facts from the masses. |
#26
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NO, ASSWIPE, there is no grand conspiracy to keep scientific facts from the masses. Are there still people who actually believe that. |
#27
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In uk.sci.astronomy Hurt wrote:
NO, ASSWIPE, there is no grand conspiracy to keep scientific facts from the masses. Are there still people who actually believe that. That there's no grand conspiracy? Yeah, sure. In fact we've formed our own Secret Club. It meets on Tuesdays. FoFP |
#28
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On 6/7/06 16:43, in article , "M Holmes" wrote: In uk.sci.astronomy Hurt wrote: NO, ASSWIPE, there is no grand conspiracy to keep scientific facts from the masses. Are there still people who actually believe that. That there's no grand conspiracy? Yeah, sure. In fact we've formed our own Secret Club. It meets on Tuesdays. FoFP Shhhh don't let on. You'll tell him the secret knock next..... -- Relf's Law? -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ "Bull**** repeated to the limit of infinity asymptotically approaches the odour of roses." -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Jaffa cakes. Sweet delicious orange jaffa goodness, and an abject lesson Why parroting information from the web will not teach you cosmology. -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Official emperor of sci.physics, head mumbler of the "Cult of INSANE SCIENCE". Pay no attention to my butt poking forward, it is expanding. -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TomGee proves his physics education is beyond measure... "I don't know that much math." - 2 April 2006 "I don't claim to know what I'm talking about" - 10 May 2006 "There is no such thing as relativistic momentum" - July 2006 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ "Puddle**** tou are on my kill file. Good bye" - Vert admits he cannot calculate \gamma for a photon and admits defeat - 2nd July 2006 PWNED -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
#29
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That there's no grand conspiracy? Yeah, sure. In fact we've formed our own Secret Club. It meets on Tuesdays. Your secret club? I thought my club was the official grand conspiracy club; and we meet on Fridays. Well usually Fridays except when Floyd is busy, then it's on Saturday. |
#30
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In uk.sci.astronomy Hurt wrote:
That there's no grand conspiracy? Yeah, sure. In fact we've formed our own Secret Club. It meets on Tuesdays. Your secret club? I thought my club was the official grand conspiracy club It is. We're the Secret Club that doesn't believe in you. and we meet on Fridays. Well usually Fridays except when Floyd is busy, then it's on Saturday. Floyd??? Hey, he's in our Club too. FoFP |
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