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I ran across an old BBC article titled Juno: The spacecraft putting sling theory to the test — Why a probe passing our planet on its way to Jupiter might end a decades-old mystery, and reveal something completely new about gravity.

The Flyby anomaly is characterized as a very tiny difference between the measured change in velocity of a spacecraft after executing a flyby maneuver, and the calculated change, based on an exhaustively thorough modeling of all of the components to the gravitational field as well as all other non-gravitational forces have been modeled.

The question Is the Flyby Anomaly still a thing? shows a nice table, and I've included it here as well. For Juno, the entry only shows ~0 with an uncertainty listed as not available.

That there is a zero suggests that Juno did provide some information, but since the uncertainty is not available, it's hard to judge this significance.

What is the nature of this zero? Did Juno help as suggested by the BBC that it might, or were there problems leading to unanticipated uncertainties?


Below: From The Flyby Anomaly: An Investigation into Potential Causes. Note the anomalous difference $\Delta$ is much larger than the estimated error $\sigma$ for flyby's before about 2005.

enter image description here

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  • $\begingroup$ About the "Note the anomalous difference $\Delta$ is much larger than the estimated error $\sigma$ for flyby's before about 2005." thing, I wonder if 2005 is when "they" noticed were starting to wonder if we are living in a simulation, so "they" added some more computing power to the universe? (humor) $\endgroup$ – uhoh Feb 14 '18 at 7:41
  • $\begingroup$ Why do you think it's notable that "the anomalous difference Δ is much larger than the estimated error σ"? That is $\sigma\Delta v$, i.e. the error on the anomaly, not the error estimated for the calculation of $v_\infty$, which would be $\sigma v_\infty$. $\endgroup$ – asdfex Mar 15 at 11:18
  • $\begingroup$ @asdfex I haven't looked at the paper in three years, so you'd have to use past tense in your comment (e.g. "why did you think three years ago that...") I'll give it a fresh read... $\endgroup$ – uhoh Mar 15 at 15:04
  • $\begingroup$ @asdfex you've omitted the rest and operative part of my sentence, which is "...for flyby's before about 2005." The key point that I'm noting is that anomalous behavior goes away after 2005 and that's guaranteed by my criteria. I haven't said that it is significant before 2005, just that it isn't after that. Please try to quote entire sentences and not just fragments thereof when combing for challenges. Thanks! $\endgroup$ – uhoh Mar 16 at 1:16
  • $\begingroup$ That's not the point. You're pointing something out as "notable" that is perfectly normal for any kind of measurement with a reasonable precision. $\endgroup$ – asdfex Mar 16 at 8:42

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