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Originally Posted by nutant gene 71
Thinking by Anderson it might have something to do with Earth's rotation would be a natural place to start, but it may not be the end solution if something is happening in space, away from Earth's known 1 AU, especially if outside this "local terrain" the value of G were to be different. Still, this is merely anecdotal evidence, not yet real science. What is heartening is that the 'mainstream' is beginning to tackle this "Pioneer" type problem with some real questions, that perhaps we don't have gravity right 'out there' even if it looks right here. I believe Anderson et al had approached ESA in the past with the idea to launch a probe to specifically measure for gravity anomalies in the outer solar system. Here is one more possible reason why such a test, to empirically test for inertia related factors (or Newton's G per Equivalence) outside our known "local terrain" of 1 G, is a darn good idea, even if still ATM for now. ... Things change, as korjik pointed out earlier, where ATM one day becomes MS.
Thanks for the heads up 'madman'!  |
While it is an interesting article, do not read too much into it. It dosent say when and where these probes were accelerated, it dosent say how well the acceleration vectors correlate with either the probe position or probe velocity vectors.
there are two major problems. First:
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"I would be very surprised if we have discovered two independent spacecraft anomalies," Anderson told SPACE.com. "I suspect they are connected, but I really do not know."
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This is utterly irrelevant. There could be a different cause for
each if the anomalies ever measured. Not likely, but not that different in likelyhood to Anderson's statement.
Second:
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For instance, the NEAR mission approached Earth at about latitude 20 south and receded from the planet at about latitude 72 south. The spacecraft then seemed to fly 13 millimeters per second faster than expected. While this is just one-millionth of that probe's total velocity, the precision of the velocity measurements was 0.1 millimeters per second, carried out as they were using radio waves bounced off the craft. This suggests the anomaly seen is real — and one needing an explanation.
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This paragraph is very frustrating in its lack of coherent science. Did NEAR approach 13mm/s faster? Did it leave 13mm/s faster? How do the approach and exit latitudes matter? What was the delta-v of the pass?
The reason I brought this up is that it can make a big difference. If the 13mm/s is only seen when receeding from the Earth, then the tiny comparative change may be a higher order geoid term in Earth's gravitational field. If it is seen when NEAR is approaching Earth, if Earth is farther from the sun than NEAR when approaching, then the acceleration vector seems to be opposite to the Pioneer anomaly. We just cant tell with this article.
On the oither hand, this is pretty interesting. They should try to make sure they have extremely accurate position data for all probes from now on.