The journal Science apparently ran a whole series on Mercury and the data sent back from the MESSENGER spacecraft. A few days ago I posted MESSENGER Is Back, on the subject of a DpSU arguing on the basis of one of those papers that “Mercury’s Surface Looks young.” MESSENGER and Mercury have turned up once before during the short time this blog has been running, so that made that post effectively Mercury II, and this III.
Wednesday’s DpSU is based on the very next paper in Science, and is called Mercury’s Fading Magnetic Field Fits Creation Model. Surprisingly, they do actually have a model – it’s just rather questionable that it fits the data.
A quick background to this is given in Mr Thomas’ article like so:
In 1974 and 1975, the Mariner 10 spacecraft measured Mercury’s magnetic field strength with its onboard magnetometer and sent the data to earth. The astronomers analyzing the data at the time found that the average field strength was 4.8 x 1022 gauss cm3, which “is about 1% that of the Earth.”
A decade later, creation physicist D. Russell Humphreys published a magnetic field model based on clues from the Bible. He reasoned that earth and the planets all shared a watery beginning, in accord with Genesis 1 and 2 Peter 3:5. He calculated what the magnetic field strength would have been at the creation by using a mass of aligned water molecules equal to the masses of each planet.
Anyway, his little model predicted that the decline in Mercury’s magnetic field between then and now would have been four percent. Mr Thomas is claiming that this ‘fits’ the recorded measurements, which gave an approximately twenty-seven percent decline over the same period. The criteria for accurate predictions in the creationist world is apparently rather low.
This confirms that Mercury’s magnetic field is rapidly diminishing, which in turn confirms that the field must only be thousands of years old—just as the creation model predicts.
Actually, no – rather, it tells us that this simplistic modelling of the earth’s field over such a time is, well, simplistic. You can’t draw conclusions directly from it about the age of anything. Indeed, if the predicted drop is nearly seven times smaller than the observation, wouldn’t that move the date for creation closer to now?
There is more to Humphreys’ planetary magnetic field ideas than this, and indeed to creationism on the subject generally. A rather good, specifically Earth related, summary can be found here, while a significantly longer one is at the Talk.Origins archives. I’ll just mention one further aspect, not mentioned in Mr Thomas’ article.
Humphreys also claims to have predicted the magnetic field of Neptune and Uranus. Here’s Tim Tompson of Talk.Origins on this subject:
Humphreys’ predictions for Uranus [20, page 146] and Neptune [20, page 147] both state that the dipole strength should be “on the order of 1024 J/T”. He connects these predictions to his theory by selecting a value for k = 0.25 in both cases, computing a dipole strength at creation, and then estimating a characteristic decay time assuming a core conductivity similar to the terrestrial planets. This brings on the estimate of 1024 J/T, but remember that the dipole at creation is an entirely free parameter. A peek at Humphreys’ table II [20, page 147] shows that the dipole for Jupiter is 1.6 × 1027, for Saturn 4.3 × 1025, and for Earth 7.9 × 1022. From these values alone, with reference to no theory at all, one can immediately see that the dipole values for Uranus and Neptune must be larger that Earth’s 1022 and smaller than Saturn’s 1025, so that anything in the 1023 to 1024 range is an obvious guess anyway. All Humphreys has to do is come up with a dipole at creation that is about the same as Saturn’s is now, and the result is going to be very nearly right. We now know the dipole values for Uranus [3.7 × 1024 J/T] and Neptune [2.1 × 1024 J/T], which do indeed agree with Humphreys’ order of magnitude predictions. But to hail this as a confirmation of his theory is not very rewarding. Indeed, it is my position that Humphreys’ theory cannot be confirmed, since it predicts at once every possible observed field, and is therefore useless for predicting anything.
k, here, is a constant in Humphreys’ equasions that can have a value of between 0 and 1, and effects the initial strength of a planet’s magnetic field back when God created it, apparently by lining up that portion of all atoms spins with each other. Part of the point is that you can move it to wherever you like to get quite a range of possible results, and you could easily have guessed a range that spanned, after all, two orders of magnatude, which would be most likely correct.
In short, I would not put too much stock in Humphreys’ predictions…
As I have forgotten to mention for nearly a year now (it’s the 5th of August 2012 as I write) there is a much more serious problem here. The real story is that the MESSENGER probe managed to record much a more accurate value for the strength of Mercury’s magnetic field than the previous craft by virtue of orbiting the planet rather than passing it by. This new value is much lower than previously thought, but nobody is seriously suggesting that the magnetic field of Mercury has decreased in magnitude in the interim.