Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax" - Philip Plait (2002)
Part IV. Artificial Intelligence
Chapter 18. Worlds in Derision: Velikovsky vs. Modern Science
n 1950, a remarkable book entitled Worlds in Collision was published. It was the culmination of a decade's work by a man who had a startling thought: what if the various disasters recorded in ancient texts were real, actual events?
The ancients experienced so many catastrophes that it almost sounds like something from a bad science fiction movie. Fire rained down from the sky, the Sun stood still during the day, floods, famines, vermin infestations-it seems like things were a bit more exciting back then. Of course, most people assume that these events were either exaggerated or were simply myths spawned from storytelling and a very human need to explain things that are beyond our understanding. But suppose we take these ancient writers at their word, and assume that these events really did happen. Can there be a simple, common cause? Could it have an astronomical basis?
Psychoanalyst Immanuel Velikovsky decided to tackle this issue. His answers to these seemingly simple questions would have massive repercussions throughout the scientific community, although perhaps not in the way he would have thought. By the time he finished Worlds in Collision and its sequel, Earth in Upheaval, he honestly felt that he had uncovered evidence that all previous scientific laws were wrong, and that we needed to seriously rethink the way the universe worked.
Many people avidly read Worlds in Collision, putting it on the bestseller list soon after it came out. It was a counterculture smash in the 1960s and '70s. His popularity is waning now, but Velikovsky still has many followers, many of whom fiercely defend his notions.
What are these notions? The basic premise espoused by Velikovsky is that the planet Venus was not formed at the same time as the other planets in our solar system. Instead, he concludes it was formed recently, only a few thousand years ago, around the year 1500 B.c. According to Velikovsky's analysis of the Bible and other ancient tomes, Venus was originally part of the planet Jupiter, which somehow split apart, ejecting Venus bodily as a huge comet. Over the ensuing several centuries, Venus careened around the solar system, encountering the Earth and Mars multiple times, affecting them profoundly. It was the gravity and electromagnetic effects of these near passes of Venus and Mars as well that caused all the catastrophes heaped upon our ancestors.
As you might guess, I disagree with Velikovsky. I'm not alone; nearly every accredited scientist on the planet disagrees with him as well. There's good reason for this: Velikovsky was wrong. Really, really wrong. The astronomical events he describes are not so much impossible as they are fantastically impossible-literally, they are fantasy.
To be fair, a lot of accepted scientific theories sound fantastic, too. Who can believe that the universe started as a tiny pinpoint that exploded, creating time and space, which then began to expand, forming the cosmos as we see it now?
What you have to remember is that the Big Bang was first proposed after many astronomical observations were made that could not be explained any other way. There has been a great deal of support for the Big Bang for decades now, and it's actually one of the most solid ideas in science. On the other hand, Velikovsky's ideas have little support from astronomical observations, and in fact many fairly well-established astronomical theories directly contradict his ideas. The difference between the Big Bang and Velikovsky's thesis is physical evidence. The former has lots, the latter has none.
Velikovsky's thesis certainly seems legitimate. It's built upon a tremendous amount of historical and archaeological research. The book has a vast number of quotes from all manner of historians, from contemporary analyses to those by the ancient Roman, Pliny the Elder. Experts in the field have many criticisms of Velikovsky's interpretations of these works, and it's quite possible that his research is historically inaccurate. To be honest, I have no expertise in this, and so I'll refrain from judging his ideas on their historical merit. However, I'll be happy to discuss them in an astronomical context.
Like most areas of pseudoscience such as astrology and creationism, it's possible to find fatal flaws in the theories without resorting to a detailed and painful analysis of every fact and figure. As a matter of fact, sometimes it pays not to nitpick; when you do, pseudoscience supporters will simply throw more facts and figures at you, hoping either to dazzle you with their database of knowledge or to confuse you beyond hope of reaching any rational conclusion. So, instead of going over his writings with a fine-toothed comb, it's a better idea to look at more general concepts-large, broad areas that contradict the basic premise. These are usually easier to explain and understand, anyway. If I mention a few details it's because I think they're important, as well as fun and interesting.
Velikovsky's main idea of Venus as tooling around the solar system and creating havoc is based on many ancient writings. Perhaps the most important biblical passage is in Joshua 10:12-13. During a massive battle with the Canaanites, Joshua knew he could win if only he had a little more time, but the day was drawing to a close. Getting desperate, he asked God to make the Sun stop its daily motion around the Earth, giving him the extra time he needed. The biblical passage reads, ". . . and the Sun stood still in the midst of heaven, and the Moon stayed, until the people had avenged themselves upon their enemy." Then, almost exactly 24 hours laterafter the battle was over-God restarted the heavens, setting the Sun and Moon in motion once more.
Today, we would interpret that-if we are particularly literalminded-to mean that the Earth's rotation stopped, so that it only appeared that the Sun and Moon were motionless in the sky. Somehow, a day later, it started its rotation again.
Velikovsky, quite literal-minded indeed, was researching this event and discovered reports of a meteor storm that supposedly happened just before the Earth's motion stopped. To him, the meteors indicated an astronomical cause for the biblical passage. This idea dovetailed neatly with other legends he found, such as those in ancient Greece. The goddess Minerva, associated at the time with the planet Venus, was born fully grown from the head of Zeus (associated with the planet Jupiter). Other cultures had vaguely similar claims of ties between Jupiter and Venus. Velikovsky suspected that these legends were actually based in fact. From there, he shaped his idea that the planet Venus was indeed literally ejected from the planet Jupiter, and subsequently encountered the Earth on multiple occasions.
It was the first such encounter with Venus that stopped the Earth's rotation. Somehow-Velikovsky is never really clear on this, but instead invokes vague claims of a previously unknown electromagnetic process-Venus was able to slow and stop the Earth's spin during an exceptionally close pass. Venus then moved off, but a day later came back for a second pass that started the Earth's rotation again. Venus itself was sent off in a long, elliptical orbit, only to pass by the Earth again some 52 years later. Over time, Venus settled down into its present orbit as the second planet from the Sun.
There are so many flaws with this idea that it's difficult to know where to start. For example, Velikovsky points to many passages in ancient texts that describe a great comet in the sky, the passing of which precedes many of these catastrophes. How to reconcile this with the planet Venus? Well, he says, Venus was ejected from Jupiter as a comet. It didn't become a planet proper until it found its way into a stable orbit around the Sun.
First, ejecting something with the mass of Venus would be very difficult to say the least. Velikovsky suggests that Venus fissioned off, flung outwards by Jupiter's rapid rotation in the same way that a dog shakes its body to spray off water after a bath. In reality, this won't work.
There are many lines of evidence showing the solar system to be billions of years old. Why would Jupiter wait until a few thousand years ago-a tiny, tiny fraction of its lifetime-to suddenly eject a planet-sized mass? The only way to shrug off this huge coincidence is to say that this is not a rare event, and that Jupiter has done it many times before. But where are these planets? If you assume all the planets formed this way, then you are left with the problem of how Jupiter formed. Since Jupiter would slow its own rotation every time this happened, it would have had to start with an impossibly high rotation rate.
Second, Venus and Jupiter have entirely different compositions. Jupiter is mostly hydrogen, the lightest element. It probably has denser elements in its core, but Venus should show at least some similarities to Jupiter. However, they're about as different as two planets can be. The chemical composition of Venus is very much like that of the Earth, so it seems unlikely that similar planets would have formed in such vastly different ways.
Third, Venus is a fair-sized planet. In fact, it has almost exactly the same mass and diameter as the Earth. Jupiter is orbited by a retinue of moons, four of which are so big that they would be planets in their own right if they didn't orbit their mighty host. These moons orbit Jupiter in nice, almost perfectly circular orbits, which is what one would expect after millions or billions of years of gravitational interaction with Jupiter and each other. (See chapter 7, "The Gravity of the Situation," for more about tidal evolution.)
Now imagine Venus plowing outward through this system. The orneriest bull in the most delicate of china shops would be nothing compared to the devastation wrought on the jovian system. The moons would get scattered, their orderly orbits perturbed by the rampaging planet on its way out bent into long ellipses. Some may even have been ejected from Jupiter completely to wander space as Venus reportedly did; yet there is no mention of these rogue moons in ancient texts.
We see no evidence of this at all in the system of moons around Jupiter. By all observations, the moons have been doing what they do now for the past billion or two years at least. If there have been any disturbances, they certainly have not occurred in the past few millennia.
Velikovsky spends quite some time in Worlds in Collision trying to show that Venus was ejected by Jupiter. He is wrong; such an event simply could not happen. It can be shown mathematically that the amount of energy needed to eject Venus would have literally vaporized the planet! In other words, whatever type of event Velikovsky envisioned to shoot Venus out of Jupiter actually would have turned Venus into a very hot, incandescent gas, exploding outwards like, well, an explosion. It certainly would not have formed a solid body able to roam the solar system. This seriously weakens his argument about Venus wandering the solar system, unless you believe in truly immense forces having incredibly benign effects. It would be like dropping an anvil on an egg and winding up with two perfectly split egg shells, one with the white inside and the other with the yolk. When forces are that huge, they rarely clean up after themselves so neatly. In reality, the egg would be a goopy mess, just as Venus would be by whatever forces Velikovsky was imagining.
Still, let's grant that some mysterious unknown force set Venus in motion. So, ignoring the genesis of Venus, is it still possible that it somehow passed so close to the Earth that it caused widespread disaster here?
In a word: no.
From his readings Velikovsky concludes that Venus passed close enough to the Earth to stop its rotation, moved off, then came back a few hours later and started the Earth moving again. However, he is very vague about the exact mechanism for this. He theorizes that perhaps the Earth didn't really slow and stop, but instead it flipped over on its axis, making the north pole become the south pole and vice versa.
Indeed, he spends dozens of pages giving evidence that the Earth didn't always spin with the north pole in the position it is now. He starts a chapter about this as follows: "Our planet rotates from west to east. Has it always done so?" He quotes ancient texts as saying that the Earth has flipped not just once, but many times.
His basis for this is pretty shaky. One passage he quotes talks about two drawings of constellations found in an Egyptian tomb. In one drawing, the constellations are represented correctly, and in the other they are reversed east-to-west, as if the Earth were spinning the wrong way. How else to account for this but to assume the Earth indeed was spinning east to west?
Actually, there are two ways. One is that the Earth is a big ball. To someone standing in the southern hemisphere, the constellations will look upside down compared to the view of someone standing in the northern hemisphere. The curvature of the Earth does this, making one person look like he is "standing on his head" relative to another. That would explain the upside-down constellations pretty well; perhaps a traveler was describing what he saw Down Under.
There is another explanation as well. Many ancients thought stars were holes in a great crystal sphere, letting the light of heaven shine through. The gods lived on the other side and therefore saw the constellations backward relative to us. Many star maps show this so-called "gods' view" of the sky. In the main corridor of Grand Central Terminal in New York City, the stars are painted on the ceiling this way. Perhaps that Egyptian drawing was showing our view of the sky versus the gods' view.
I find either of these explanations a bit more palatable than calling for the Earth to flip over.
And again, even if we do grant that the Earth flipped over, Velikovsky would have us believe that another pass of Venus 24 hours later flipped the Earth back the way it was, and spinning at the same rate. To put it very mildly, this is pretty unlikely.
There are still two more massive, basic, truly fatal flaws to Velikovsky's Venus theory: one is that we still exist, and the other is that the Moon is still around.
Velikovsky goes to great pains, over hundreds of pages in his book, to relate the various disasters that befell mankind as Venus loomed hugely in the sky. All of these events call for Venus to get pretty close to the Earth. At one point, to explain such things as manna falling from heaven and the Egyptian plague of vermin, he states that Venus gets so close that its atmosphere flows into the Earth's own air.
This premise, that manna and insects came from Venus to the Earth, is suspect at best. We now know that the surface of Venus has an incredibly high temperature, over 900° Celsius (1,600° Fahrenheit), hot enough to melt lead. It's difficult to imagine what kind of bug could survive such withering heat. It's also hard to see how manna-a life-sustaining compound-could form on Venus. After all, the atmosphere of Venus is mostly carbon dioxide and sulfuric acid. If a few billion tons of these substances gets dumped into the air here on Earth, the effect would hardly be conducive to life. Quite the opposite.
There are other physical effects of a Venusian near miss. Despite its differences, Venus does have some similarities to the Earth. They have almost exactly the same mass and diameter. That means they have about the same gravity. For the air of Venus to flow onto the Earth, there would need to be about an equal pull from both planets on the air, with a little bit more of a pull from the Earth. Even being outrageously generous, their nearly equal gravity means that Venus would have to be closer than 1,000 kilometers (600 miles) from the surface of the Earth.
Imagine! A planet the size of the Earth passing just 1,000 kilometers overhead would be just about the most terrifying event I can imagine. Venus would literally fill the sky, blocking out the Sun and stars. Even at interplanetary velocities it would be vastly huge in the sky for days or weeks, and would be brighter than hundreds of full Moons.
Yet, no mention of this incredible spectacle is made in ancient texts.
Worse, the tides from Venus on the Earth would be huge, kilometers high. The earthquakes would have been more than terrible; they would have destroyed everything, and I mean everything. It would make the sweatiest vision of biblical apocalypse look like a warm spring day. That close a pass by something like Venus would have sterilized the surface of the Earth, killing every living thing on it. Had it happened, Velikovsky wouldn't have been around to write his book. To his credit, Velikovsky assumes that there would have been earthquakes and the like, but he underestimates the effect of such a near passage by a factor of millions.
Even granting that humanity somehow survived this apocalypse, there is still a problem. The Moon orbits the Earth at a distance of 400,000 kilometers. If Venus were to get so close to the Earth that it could actually exchange atmospheric contents, it would have to get closer to us than the Moon. If that had happened, the Moon's orbit would be drastically changed. Usually when you take three objects, two of them massive and one less so, and let them interact gravitationally, the least massive one is ejected from the system completely. In other words, under almost every circumstance, had Venus come that close to the Earth, the Moon would have literally been flung into interplanetary space. At the very least its orbit would have been profoundly changed, made tremendously elliptical.
The orbit of the Moon is elliptical, but nowhere near as stretched out as it would have been after a close encounter with Venus. The very fact that the Moon-and we, too-are here at all shows that Velikovsky was wrong.
There's still one more thing. The Hebrew calendar, still going strong after nearly 5,800 years, is based on cycles of the Moon. Any passage by Venus would have changed the length of time it takes the Moon to orbit the Earth. Yet, if we look to the Hebrew calendar, we see that it hasn't changed for nearly six millennia. The events described by Velikovsky took place 3,500 years ago, thousands of years after the Hebrews started their calendar. This means that the Moon's orbit has not changed measurably since long before the biblical disasters took place.
Remember, Velikovsky used ancient texts to support his beliefs. Yet, here we see that one of the most basic of all ancient tools, the calendar, directly and completely refutes his hypothesis. Had Venus done any of the things Velikovsky claimed, the Moon's orbit would have changed.
Finally, according to Velikovsky, after Venus was done palpating and poking the Earth, it finally calmed down and settled into its present orbit. Remember, if this happened it's far more likely that Venus' orbit would be a highly eccentric ellipse rather than a circle. Yet Venus has the most circular orbit of all the planets, matched only by Neptune. If we accept that Venus actually went through all these Velikovskian gyrations, we would at least expect it to have some mild eccentricity, yet Venus' orbit is difficult to distinguish from a perfect circle.
Later in his book, Velikovsky tried to explain how all the orbits of the moons and planets could have become more circular. He proposed that there is an electromagnetic force that emanates from the planets and the Sun, and indeed it is this force that flipped the Earth over and created all the problems. However, today we see absolutely no evidence whatsoever that such a force exists in anywhere near the strength needed to do a fraction of what he claims. If such a force ever existed, it stopped working shortly after the events described in the Book of Exodus. Also, if such a force existed, why are some planets' and moons' orbits not perfect circles, or even close to them? We see some objects on highly elliptical orbits; comets are a good example. Why didn't this force affect them?
So, Velikovsky would have us believe that all these biblical disasters occurred due to some mysterious force, unknown in nature, that came to the planets, did its nefarious deeds-but only on some objects, ignoring others-and then evaporated again. It left not a trace on the planets, either, as the solar system looks exactly like it had evolved naturally over billions of years.
This is not science. In fact, it would be just as legitimate to invoke the Hand of God. In other words, there is hardly a need for Velikovsky to go to such great lengths to try to get science to corroborate his beliefs. His use of a force unknown to science negates the entire purpose of writing the book in the first place, which was to find a scientific grounding for ancient texts.
So if Velikovsky was so utterly and obviously wrong, why do so many people still follow his work and think he was right?
This question is more philosophical than practical. However, part of the answer lies in the way the scientific community treated Velikovsky when he published his book.
Initially, in 1950, when the Macmillan publishing house was preparing the manuscript for publication, the scientific community caught a whiff of it. In particular, a Harvard astronomer named Harlow Shapley wrote several vitriolic letters to the editors at Macmillan saying-correctly, mind you-that Velikovsky's ideas were wrong, and that Macmillan was doing everyone a big disservice by publishing them. At the time Macmillan was a very large publisher of scientific textbooks, and Shapley said that the publisher's reputation would be damaged by selling Worlds in Collision. From what I have read, there were intimations, although not direct threats, that Shapley would use his considerable reputation to pressure other scientists to boycott Macmillan's books.
This was a serious problem for the publisher. When Velikovsky's book came out it rocketed onto the bestseller list, no doubt aided by the controversy. It was a huge money maker. Macmillan, however, also made a lot of money from textbooks. In one of the worst publishing decisions ever, bowing to the pressure, they transferred the rights to Worlds in Collision and its sequels to Doubleday, which suddenly found themselves printing a book they couldn't keep on the shelves. This only added to the book's mystique, aiding its sales.
With sales booming, the scientific pressure against Velikovsky continued. His book became a favorite among college students, especially in the 1960s when intellectual rebellion was fashionable. The situation became so bad, as far as "establishment" scientists went, that the American Association for the Advancement of Science sponsored a semipublic debate in 1974 between Velikovsky and his detractors in an attempt to discredit the book once and for all. One of the leading scientists in the debate was Carl Sagan, who by then was something of a media darling, a professional skeptic, and well-known by the general public.
I did not attend this debate, as I was only nine years old at the time. However, I have read many accounts of this infamous meeting on the web and in books. Which side won, Velikovsky's rebels or mainstream science? In my opinion, neither. I'd say they both lost. Velikovsky made several rambling speeches that neither supported nor detracted from his cause, and his supporters came across more as religious zealots than anything else. On the side of science, there was much posturing and posing. Sagan-for whom I have tremendous respect both as a scientist and as someone who popularized teaching astronomy to the public-did a terrible job debunking Velikovsky's ideas. He made straw-man arguments, and attacked only small details of Velikovsky's claims.
The book Scientists Confront Velikovsky [Cornell University Press, 1977] transcribes the talks given by scientists at the meeting. As it happens, Velikovsky's talk is not in the book. Sagan was given an extra 50 percent more space to rebut Velikovsky's arguments using arguments not in Sagan's original paper, but Velikovsky was not given any room to counter Sagan's rebuttals. Because of this word-length dispute, Velikovsky withdrew his paper from the book. In the book, Sagan gives his arguments against Velikovsky and expands upon them even further in his own (otherwise excellent) book, Broca's Brain. Again, Sagan's arguments are not all that great. For example, he gives the energy criteria necessary for Jupiter to eject Venus but then ignores Jupiter's own rotation, which is crucial for the analysis. On his web site about the affair, fellow scientist and author Jerry Pournelle calls Sagan's performance "shameful."
Sagan's and Shapley's reactions were not uncommon in any way among scientists. Many of them loathed the very idea of Velikovsky writing this book and the fact that he was getting rich from it too. But the extreme amount of bile and bitterness only helped make Velikovsky a martyr. To this day he is practically revered by his followers.
Thomas Jefferson once wrote, "I know no safe depositary [sic] of the ultimate powers of the society but the people themselves; and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education." Perhaps, if Shapley and his fellow scientists had heeded Jefferson, Worlds in Collision would be just another silly pseudoscientific book collecting dust next to ones about UFO aliens curing pimples using homeopathic crystals. Instead, even after half a century, it can be found on bookshelves today.
There's an ironic footnote to this episode in the history of science. Certainly, scientists of the day dismissed Velikovsky because his assertions clearly flew in the face of everything known about physics and astronomy, then and still today. They also ridiculed him because, at the time, it was thought that the planets were fairly static. Things didn't change much. Any change that occurred was gradual, slow, glacial. Nothing happened suddenly. This type of thinking is called uniformitarianism.
However, this tide was turning. As observations of the planets improved, including our own, we started to learn that things didn't always happen at a stately rate. The Moon is covered with craters; it was once thought that these were volcanic, but around the same time as Worlds in Collision was published, scientists were starting to speculate that at least some lunar craters were formed from meteor impacts. Venus' surface bears evidence that some massive event resurfaced the whole planet some hundreds of millions of years ago, and it looks like there have been many mass extinctions caused by individual catastrophic events here on Earth.
Today we understand that both uniformitarianism and catastrophism describe the history of our solar system. Things mostly go along slowly, then are suddenly punctuated by rapid events.
Velikovsky supporters claim that he was simply ahead of his time, and his theories of catastrophism were denied their due. This is silly; just because he used the idea that catastrophes happened doesn't mean that any of the things he described were right. But it is rather funny that scientists of the day were wrong in many of their assertions of uniformitarianism as well.
Still, that's the difference between science and pseudoscience: scientists learn from their mistakes and abandon theories that don't pan out. Velikovsky was wrong, as were the scientists at the time. But science-real science-has moved on. Maybe we can all learn something from this.