Mercury’s magnetic message is not yet clear
Published: 16 February 2008 (GMT+10)
A known anti-creationist, Richard M of the USA, wrote to dispute whether Russ Humphreys really had made a genuinely falsifiable prediction in his recent article Magnetic message from Mercury. And in a supplementary feedback, V.T. of Romania comments favourably on Science, Creation and Evolutionism, CMI’s rebuttal to the NAS booklet Science, creation and evolutionism.
I am still trying to digest the article ‘Magnetic message from Mercury’, by D. Russell Humphreys, as published on your website on February 4, 2008. I remain puzzled by the remark on the last paragraph: ‘ “ … the mean dipole has the same intensity to within a few percent and has the same slight tilt … ” This is consistent with my [1984?] prediction.’1 As I understand your prediction, you expected the magnetic field to have decreased since 1975. If NASA had announced such a finding, you would have called it ‘consistent with my prediction.’ And when NASA noted that there had been no statistical change, this too was consistent with your prediction. How strong a prediction is it when both results are claimed as consistent?
The prediction itself is strong, but we may have to wait until the end of 2011, or perhaps much longer, for observations to be strong enough to test it. The observational reports from the Messenger mission analyzers are presently too vague to confirm or deny the decrease my theory predicts. This graph shows the problem:
The blue vertical line on the left shows the results from the Mariner 10 mission to Mercury in 1975, as analyzed by N. F. Ness of the NASA-Goddard Space Flight Center. The top and bottom horizontal bars on the blue line are the error limits in Ness’s 1979 report,2 showing the limitations the data put on his estimate of Mercury’s magnetic dipole moment (its magnetic strength).
The vertical green line shows the range of my prediction of the dipole moment by 2011, ‘4 to 6 percent weaker than the field in 1975.’ 3 The upper dashed black line shows a 4% decrease (by 2011) from the upper bound of Neff’s estimate. The lower dashed black line shows a 6% decrease from the lower bound of his estimate. The solid black line connects the midpoints of Neff’s estimate and my prediction.
Now comes the hard part … reading the tea leaves of the most numerical thing the Messenger team has said so far (February 9, 2008) about the magnetic field the first 2008 flyby recorded:
‘ … the mean dipole has the same intensity to within a few percent [of the 1975 measurements] …’4
What does ‘a few percent’ mean? If I’d said it, I would mean more than two percent and up to four or five percent. And which direction is the measurement, above the old one or below it? And finally, are they relating the current measurement to the center of Neff’s estimate, or to one of the bounds? The red-yellow bar shows my outside guess as to the range of what the Messenger team meant. The top of the bar is 5% above Neff’s upper bound, and the bottom of the bar is 5% below Neff’s lower bound. You can make your own guess as to what ‘a few’ means and put it somewhere within the red-yellow bar.
The main point is that the red-yellow bar overlaps a considerable portion of the vertical space between the dotted lines. Therefore the 2008 observations are consistent with my prediction, meaning they fail to reject it. However, they don’t validate it either. Even when we get complete magnetic data from the first flyby, they may not be accurate enough. That is why I wrote, ‘The 2008 results, coming only from several brief flybys, probably won’t be accurate enough to detect a decrease clearly.’ I hope that after a year of orbiting in 2011 and detailed analysis afterward that we can say something more definite. If not, we’ll have to send another spaceprobe to Mercury in another few dozen years! Now, you may ask, what did I mean by ‘few’?
Striving for clarity,
D. Russell Humphreys
Institute for Creation Research
Rebuttal to NAS appreciated
Vasile T of Romania wrote:
I have read the CMI’s response to NAS on the brochure Science, creation and evolutionism, and I must say Dr Sarfati excels again. Such a clarity of arguments, straight defense and attack, clear identification of opponent’s weaknesses and errors and through defense of the biblical creation is rare for me to read in a single piece of article.
I am glad Dr Sarfati joined a biblical creation apologetics ministry to use his God-given gift of intellect and brain-power for the advance of His Kingdom and the scattering of unhealthy evangelical positions on Genesis. He could have a high academic career or maybe, but instead he chose to defend Christianity in one of its least protected areas.
Ed. note: We also have a PDF version available, with live links and illustrations, if anyone wants to post it on their own site, to make it available to their web visitors for either viewing or downloading. There is no cost or other obligation; we believe that getting this booklet ‘out there’ in this way is a vital way of cooperating in combating what Dr Sarfati calls this latest NAS evolutionary ‘agitprop’.
- Humphreys, D.R. 1984. The Creation of planetary magnetic fields. Creation Research Society Quarterly 21(3):140–149. Return to text.
- Ness, N.F., 1979, The magnetic field of Mercury, Physics of the Earth and Planetary Interiors, 20(2–4):209–217. Use Ness’s more accurate result in the second-to-last paragraph of the abstract and his error bars (presumably 1-sigma) of (± 18) γ. Ness’ nomenclature: 1 γ = 10-5 gauss; R M = 2439 km (bottom of p. 215); 1 gauss cm3; = 10-3 A m2. Return to text.
- Humphreys, D.R., July/August 2004. Mercury’s Messenger, Creation Matters 9(4):1,9. Return to text.
- Science results and new images from messenger’s first mercury flyby, Messenger news conference, 30 January 2008. Return to text.