While meteorites are the oldest datable objects in the solar system, they are remnants, not of a constructive, but of a destructive process. There are no demonstrably pristine bodies drifting round the solar system, and meteorites cannot be used to measure its age. The age of the solar system, including the Earth, must be significantly greater than the meteorites. As Scott et al. (2007) admit, the ‘record of planetesimal and protoplanet accretion recorded in meteorites is not consistent with planetary accretion and disk evolution models’.
The relative and absolute ages of meteorites are determined by radioisotope dating, whereby the proportion of a radioactive element (normally 26Al) to its decay product (normally 26Mg) allows the investigator to calculate how long it took for one to decay into the other. The oldest such dates mark the point at which the cooling of the matrix sealed the system, preventing the isotopes from exchanging with their surroundings. Without such isolation, radioisotope dating would give a false result.
Isotopic closure does not therefore represent year zero. There was an unknown period of existence prior to that point. Chondrules, for example, were previously part of a planet that had undergone high-temperature heating. In the course of heating up, the planet’s interior might have undergone a degree of differentiation, whereby heavy minerals and elements separated out and sank towards the centre, and prior to that there might have been a period when the planet was cooler. In the absence of older radioisotope dates there is no telling how long that period was. ‘Growing evidence exists that chondritic meteorites represent the products of a complex, multi-stage history of accretion, parent body modification, disruption and re-accretion’ (Sokol et al. 2007).
In order to arrive at an absolute date, intervals based on short-lived radioisotopes have to be linked to a chronology based on long-lived isotopes. Short-lived isotopes can provide only a floating chronology, terminating with the extinction of the parent isotope, and that chronology will be valid only if the distribution of the parent and daughter isotopes through the whole solar system was initially homogeneous. Otherwise meteorites from different bodies will yield different ages even if their age is the same. The whole nebula hypothesis depends on the assumption of homogeneity. But it may not in fact be correct (Kunihiro et al. 2004, Brennecka et al. 2009). Chondrules show a span of ages as long as the longevity of 26Al itself, and can yield different ages even within the same meteorite. Iron-poor chondrules, for instance, tend to yield slightly older dates than iron-rich chondrules. Some CAIs show no evidence of live 26Al at all at the time of formation. On the other hand, one would not expect homogeneity if isotopes were synthesised as a function of increasing heat and pressure through the interior of a planet. At this point in time radioisotope dates, it appears, can reliably give only an approximate indication of relative chronology.
It is also doubtful whether radioisotope dating can provide an absolute chronology. Creation theory postulates that rates of radioactivity have exponentially decreased over time. No fragment has survived from the original world, because radioactivity and thermonuclear fusion melted the interiors of the rocky planets, blanketing their surfaces with magma. Earth was not exempted, although in its case the heat of the upwelling magma was mitigated by a large body of water beneath the former land. Mercury shed the greater part of its mantle (insofar as it had differentiated into core and mantle, differentiation may have continued after shedding). Planets larger than Earth and the original Mercury exploded entirely.
- First, the ‘storage problem’. CAI particles are thought to be the first condensates from a primeval nebula. But in that case, how is it that these particles failed to accrete with other accreting material in the protoplanetary disc for up to 3 million years? How did they survive at all when gas drag should have caused them to spiral into the Sun within a few tens of thousands of years (Bizzarro et al. 2004, Rudraswami & Goswami 2007)?
- The different compositions of CAIs and chondrules suggest that they formed in different parts of the solar nebula – CAIs close to the Sun, chondrules further out. It is not clear, however, how CAIs and chondrules could have remained in separate regions for up to 3 million years, nor how CAIs could have drifted in the opposite direction to gas drag in order to mix with chrondrules beyond Mars.
- CAIs and chondrules were mostly just millimetres in size. Gas drag should have caused them to spiral into the Sun within a few tens of thousands of years. The dating evidence that they lingered in the disc for 2-3 million years is inconsistent with the lifespan of small particles in the early solar system (Bizzarro et al. 2004, Rudraswami & Goswami 2007). Even more problematic is the inference that CAIs formed close to the Sun and then drifted in the opposite direction, beyond Mars.
- As we have seen, many investigators are agreed that chondrules originated in impacts: sudden, brief, catastrophic events. The main difficulty with this view is that chondrules sharing the same origin seem to have gone on forming for over a million years (e.g. Rudraswami et al. 2008).
- Differentiated meteorites come from parent bodies that were once molten. Radioisotope dating, however, often gives ages too late for the heat energy to have come from the decay of short-lived isotopes. These would have been largely exhausted and the heat from them would have radiated away (Baker et al. 2005). Indeed, even if the asteroids had accreted immediately after the synthesis of 26Al, the heat generated would would have been insufficient to melt them. The maximum temperature reached would have been around 940 K, far below both the 1260 K threshold at which iron starts to melt and the 1600 K threshold at which silicates begin to segregate (Kunihiro et al. 2004).
These problems and inconsistencies are evidence that rates of radioactivity were dramatically higher at the time, causing radioisotope dates to be correspondingly exaggerated.
The presence of short-lived radionuclides, calcium-aluminium-rich condensates and silicate-rich melt droplets in the oldest meteorites is no coincidence. Ad-hoc surmises about supernovas, about the solar system having originated from a dust-rich nebula, about condensates and melt droplets lingering in separate parts of the nebula for millions of years and then coming together fall short of the mark. Everything in the chondrites is of a piece. Asteroids, comets and moons tell the same story, one that goes back to a brief episode in history when the whole solar system was given over to destruction. Nothing is as it was when it was created.
Scientists send probes into outer space because, although they have creation-excluding preconceptions about what they will find, they need to have them verified. Frequently, they are not verified. Recent recognition that asteroids do not form an orderly compositional gradient across the main belt resulted in ‘major changes in the interpretation of the history of the Solar System’. Analysis of the comet Wild 2’s composition resulted in a ‘complete revision of our understanding of early-stage processes in the solar nebula’. A complete ‘revision’. Such rethinks will never involve a questioning of the solar nebula itself. That is taboo. In the same way as there is freedom of religion in Islamic countries so long as the religion is Islam, so there is freedom of scientific inquiry in Western countries so long as the account of origins is a scientific one – that is, one that promotes the dogma that the universe created itself.
The existence of asteroids and their particular compositions affect our understanding of how the world originated. It may not be irrelevant to note that the Bible, considered by some to encapsulate an understanding that comes from the Creator himself, though most people dismiss the idea, knew about their existence long before 20th-century astronomers became aware of them. Isaiah (8th century BC) says there is coming a day of vengeance against the nations, at which time all the host of heaven shall fall like leaves falling to the ground (Isa 34). Haggai (6th century BC) says that God will once more shake the heavens and the earth (Hag 2:6, 21, Heb 12:26). John (disciple of Jesus) saw a vision in which the Moon became like blood (glowing from asteroid impacts?) and stars fell to the Earth like figs shaken from the tree by a strong wind (Rev 6:12f). At the first trumpet blast the Earth was pelted with ‘hail and fire’, burning up a third of the planet’s vegetation (Rev 8). At the second, a great burning mountain fell into the sea. At the third, another asteroid hit the Earth, poisoning a third of its waters, and at the fifth, yet another. Peter says that Earth and all man’s works in it will be destroyed (II Pet 3:10).
The asteroids in question will not be those between Mars and Jupiter but those much nearer the Earth, waiting for the cosmic equivalent of a strong wind – perhaps a coronal mass ejection – to blow them our way. Let the earth hear, and all that fills it (Isa 34:1).