Jupiter, there is no way it could have accumulated such impacts there. The clear conclusion from the craters of Venus is, therefore, that Venus has for billions of years been an object exposed to interplanetary collisions-in direct contradiction to the fundamental premise of Velikovsky’s hypothesis.
The Venus craters are significantly eroded. Some of the rocks on the surface of the planet, as revealed by the Venera 9 and 10 photography, are quite young; others are severely eroded. I have described elsewhere possible mechanisms for erosion on the Venus surface-including chemical weathering and slow deformation at high temperatures (Sagan, 1976). However, these findings have no bearing whatever on the Velikovskian hypotheses: recent volcanic activity on Venus need no more be attributed to a close passage to the Sun or to Venus’ being in some vague sense a “young” planet than recent volcanic activity on Earth.
In 1967 Velikovsky wrote: “Obviously, if the planet is billions of years old, it could not have preserved its original heat; also, any radioactive process that can produce such heat must be of a very rapid decay [
If, as Velikovsky believes, Venus were completely molten only a few thousand years ago-from planetary collisions or any other cause-no more than a thin outer crust, at most ~ 100 meters thick, could since have been produced by conductive cooling. But the radar observations reveal enormous linear mountain ranges, ringed basins, and a great rift valley, with dimensions of hundreds to thousands of kilometers. It is very unlikely that such extensive tectonic or impact features could be stably supported over a liquid interior by such a thin and fragile crust.
PROBLEM X. THE CIRCULARIZATION OF THE ORBIT OF VENUS AND NONGRAVITATIONAL FORCES IN THE SOLAR SYSTEM
THE IDEA that Venus could have been converted, in a few thousand years, from an object in a highly elongated or eccentric orbit to its present orbit, which is-except for Neptune-the most nearly perfect circular orbit of all the planets, is at odds with what we know about the three-body problem [8] in celestial mechanics. However, it must be admitted that this is not a completely solved problem, and that, while the odds are large, they are not absolutely overwhelming against Velikovsky’s hypothesis on this score. Furthermore, when Velikovsky invokes electrical or magnetic forces, with no effort to calculate their magnitude or describe in detail their effects, we are hard pressed to assess his ideas. However, simple arguments from the required magnetic energy density to circularize a comet show that the field strengths implied are unreasonably high (Appendix 4)-they are counterindicated by studies of rock magnetization.
We can also approach the problem empirically. Straightforward Newtonian mechanics is able to predict with remarkable accuracy the trajectories of spacecraft-so that, for example, the Viking orbiters were placed within 100 kilometers of their designated orbit; Venera 8 was placed precisely on the sunlit side of the equatorial terminator of Venus; and Voyager 1 was placed in exactly the correct entry corridor in the vicinity of Jupiter to be directed close to Saturn. No mysterious electrical or magnetic influences were encountered. Newtonian mechanics is adequate to predict, with great precision, for example, the exact moment when the Galilean satellites of Jupiter will eclipse each other.
Comets, it is true, have somewhat less predictable orbits, but this is almost certainly because there is a boiling off of frozen ices as these objects approach the Sun, and a small rocket effect. The cometary incarnation of Venus, if it existed, might also have had such icy vaporization, but there is no way in which the rocket effect would have preferentially brought that comet into close passages with the Earth or Mars. Halley’s comet, which has probably been observed for two thousand years, remains on a highly eccentric orbit and has not been observed to show the slightest tendency toward circularization; yet it is almost as old as Velikovsky’s “comet.” It is extraordinarily unlikely that Velikovsky’s comet, had it ever existed, became the planet Venus.
SOME OTHER PROBLEMS
THE PRECEDING ten points are the major scientific flaws in Velikovsky’s argument, as nearly as I can determine. I have discussed earlier some of the difficulties with his approach to ancient writings. Let me here list a few of the miscellaneous other problems I have encountered in reading
On page 280 the Martian moons Phobos and Deimos are imagined to have “snatched some of Mars’ atmosphere” and to thereby appear very bright. But it is immediately clear that the escape velocity on these objects-perhaps 20 miles per hour-is so small as to make them incapable of retaining even temporarily any atmosphere; close-up Viking photographs show no atmosphere and no frost patches; and they are among the darkest objects in the solar system.
Beginning on page 281, there is a comparison of the Biblical Book of Joel and a set of Vedic hymns describing “maruts.” Velikovsky believes that the “maruts” were a host of meteorites that preceded and followed Mars during its close approach to Earth, which he also believes is described in Joel. Velikovsky says (page 286): “Joel did not copy from the Vedas nor the Vedas from Joel.” Yet, on page 288, Velikovsky finds it “gratifying” to discover that the words “Mars” and “marut” are cognates. But how, if the stories in Joel and the Vedas are independent, could the two words possibly be cognates?
On page 307 we find Isaiah making an accurate prediction of the time of the return of Mars for another collision with Earth “based on experience during previous perturbations.” If so, Isaiah must have been able to solve the full three-body problem with electrical and magnetic forces thrown in, and it is a pity that this knowledge was not also passed down to us in the Old Testament.
On pages 366 and 367 we find an argument that Venus, Mars and Earth, in their interactions, must have exchanged atmospheres. If massive quantities of terrestrial molecular oxygen (20 percent of our atmosphere) were transferred to Mars and Venus 3,500 years ago, they should be there still in massive amounts. The time scale for turnover of O2 in the Earth’s atmosphere is 2,000 years, and that is by a biological process. In the absence of abundant biological respiration, any O2 on Mars and Venus 3,500 years ago should still be there. Yet we know quite definitely from spectroscopy that O2 is at best a tiny constituent of the already extremely thin Martian atmosphere (and is likewise scarce on Venus). Mariner 10 found evidence of oxygen in the atmosphere of Venus-but tiny quantities of atomic oxygen in the upper atmosphere, not massive quantities of molecular oxygen in the lower atmosphere.
The dearth of O2 on Venus also renders untenable Velikovsky’s belief in petroleum fires in the lower Venus atmosphere-neither the fuel nor the oxidant is present in appreciable amounts. These fires, Velikovsky believed, would produce water, which would be photodissociated, yielding O. Thus Velikovsky requires significant deep atmospheric O2 to account for upper atmospheric O. In fact, the O found is understood very well in terms of the photochemical breakdown of the principal atmospheric constituent, CO2, into CO and O. These distinctions seem to have been lost on some of Velikovsky’s supporters, who seized on the Mariner 10 findings as a vindication of
Since there is negligible oxygen and water vapor in the Martian atmosphere, Velikovsky argues, some other constituent of the Martian atmosphere must be derived from the Earth. The argument, unfortunately, is a
