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Is the Solar System's Cratering Really Meteoritic?
Author: Greg Alexander
Date: 3rd March 2004.
It is now accepted as a scientific fact that the cratering which is so evident throughout much of the Solar System was the result of cataclysmic meteoritic bombardment. However according to the author of the present article this is not beyond dispute and there are a number of objections that can be raised against this theory.
Firstly we are informed that it is sometimes the case that debris from these impacts can travel from one heavenly body to another (such as for example with the meteorites from Mars which have landed on Earth). But why is this same material not also found in orbit around the parent bodies they originated from?
In the case of Mars the quoted escape velocity is around 5 km/sec, so any debris leaving its gravitational field would have to be travelling at at least this speed. Closer to home the escape velocity of our own Moon is 2.38 km/sec, alot less than that for Mars being of far smaller dimensions. The Moon of course does not have an atmosphere so there is no obstacle in this respect. According to the accepted mathematics the escape velocity is always greater than the orbital velocity by a factor of √2, so in the case of the Moon the orbital velocity (depending upon the altitude) would always be less than 1.68 km/sec.
But how would any debris from a meteoritic impact then find its way from the point of impact into orbit? Would the material for example not either leave the Moon altogether or simply fall back down again having travelled part way round the lunar globe? Of course for a vast majority of the material this would indeed be the case but it is still statistically probable that some of the material would obtain a circular orbit for the following reasons:
For a satellite to achieve a circular orbit it needs an orbital velocity ‘v’ at an altitude ‘x’. On the other hand in the case of a projectile leaving the lunar surface at an oblique angle, both a horizontal and a vertical vector would apply. The vertical vector takes the object up and away from the lunar surface whereas the horizontal vector causes it to travel along the lines of latitude and longitude of the lunar surface. Of course continually pulling the object back down again, and hence working against the vertical vector, is the Moon’s gravitational pull. This causes the vertical velocity vector to gradually decrease with time until eventually it reaches zero. But if this occurs at the exact point in time when the object is at an altitude of ‘x’ and when the horizontal velocity vector (which has remained unchanged for all this time) is the same as the required orbital velocity ‘v’, then surely the object would have achieved a circular orbit?
Of course it is often the case that ballistic trajectories are considered as being elliptical in nature with both sides of the ellipse intersecting the planets surface but strictly speaking this only applies in the case of a ‘flat Earth’.
The net result therefore is that statistically speaking only a small fraction of the material thrown out by the impact would actually achieve a circular orbit but in addition there is also the possibility of an elliptical orbit (as distinct from the ballistic trajectory described above). With the numerous explosive impacts which are said to have occurred on the Moon such as the larger ones which are said to have formed the ‘Seas’, surely there should be a whole host of such material in orbit around the Moon to this day? However neither robotic nor manned missions to the Moon have ever revealed any of this and neither has any Earth based telescopic observation. Of course if such material did exist it could have proved a significant obstacle to the Apollo missions.
So where is this debris which theory so clearly predicts should be in orbit around the various planets and moons of the Solar System? Would its absence not indicate that the craters were perhaps not caused by impacts from meteorites at all but by some other process? Moreover there is plenty of other evidence which would indicate that they were not, and the surface of the Moon offers a very good example in this respect. If the lunar craters are studied in detail it is possible to observe that many have a pronounced polygonal shaping to them. This would tend to suggest that their walls had somehow set in this shape from an original liquid state. Also the impact theory can’t sufficiently explain why many of the craters have smooth sided, raised rims to them as well as central mountain peaks.
Further evidence casting doubt on the meteoritic origin of the cratering is the fact that the Moon’s ‘dark side’ is so apparently lacking in Seas. If the latter were the result of monumental impacts early on in the lunar history, why did they only impact with the one side and not the other? Considering this heavenly body rotates once every 27.3 days surely they should be evenly distributed as a result? We could also ask why such impacts only occurred very early on in the Moon’s history and not during later periods as well as larger meteoritic bodies are statistically no more likely to strike the Moon than the smaller ones are?
Indeed the mathematics would also apparently underline the fact that the craters are not meteoritic in origin. If it can be shown that the equation of classical physics defining the energy of motion is incorrect and should actually be replaced by the existing equation for momentum (see my webpage in the link listed below, “Are ‘the Laws of Physics’ Wrong?”), this would surely suggest that the meteorites would not explode upon impact anyway. Of course this inevitably would alter the overall appearance of the impact craters and possibly in the following manner: They would tend to be far smaller, would not be perfectly round and would also be partly filled with the material which had created them.
This observation would also change the status of the Earth’s own Meteor Crater at Barringer, Arizona. Ariel photographs of the formation have always appeared slightly suspect anyway as they reveal that the crater has a pronounced square shaping to it. Even though opinion has now become set in favour of a meteoritic origin, in the past volcanism has also been suggested.
It was the case that at one time two rival theories were in contention as to the origin of the craters on the Moon. The first stated that they were volcanic and the second that they were meteoritic. However the former theory was finally discarded after the Apollo missions which apparently proved once and for all that they were caused by meteorites. Indeed the volcanic theory seems slightly laughable today because volcanoes, or at least as they appear on the Earth, usually take the form of tall cones in which a crater is only found at the very summit. The only really earthly equivalent of a lunar crater is perhaps the caldera crater which is basically a volcano which has exploded. Is it possible that the lunar craters are caldera craters? A further theory however that was also in circulation, and indeed first suggested by Robert Hooke, was that when the Moon’s surface was still molten, gases percolated through it leaving rounded scars. Indeed this is the favoured suggestion of the present author.
If it is the case therefore that the cratering, which is so evident throughout much of the Solar System, was not actually caused by meteorites at all but by some other geological process, this must surely put astronomers in quite a difficult position indeed. For example how are we to explain the cratering on the surfaces of the asteroids? As the latter are considered to be made of metamorphic rock, internal causation has to be ruled out as their surfaces never actually melted. A similar difficulty would exist for the icy moons of the outer planets. Since extensive cratering is often present on their ice laden crusts, many of which resemble those found on our own Moon, how are we to explain their origin from internal causation?
Indeed the smaller craters encountered on the Moon by the Apollo astronauts would appear slightly challenging as well. As bowl shaped hollows in the lunar dust (or regolith), it again would not be possible to explain their origin from geological processes and one wonders whether the meteoritic craters in their new form would actually look like this either. (Indeed smaller craters of a similar form also appear on the surface of Mars). Moreover considering that the meteorites perhaps don’t explode upon impact anyway, would this not result in the fact that the vast majority of the loose material present on the surface of the Moon (including both the dust and the rock) would actually be asteroidal in origin and would not therefore actually count as ‘Moon rock’ at all?
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