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Christopher GraneyDecember 26, 202012 min read

From the Vatican Observatory: Commentary on ‘Cosmos: Possible Worlds’

This article, written by Christopher M. Graney, was originally posted by the Vatican Observatory’s blog, Sacred Space Astronomy, under the title “Cosmos: Possible Worlds,” 4-6: Screaming from the Bleachers. It is part of a series of commentary on the TV program, Cosmos: Possible Worlds. All past and future posts on the series can be found here.

Neil deGrasse Tyson’s Cosmos: Possible Worlds is on TV this fall. It is great to see a popular show about science and scientists—a popular show that is educational. I am a big Cosmos fan. But of course, the show could always be better! Maybe a lot better.

Episodes 4 (“The Cosmic Connectome”) and 5 (“Vavilov”) were about the brain, and about genetics and agricultural science, respectively. On these topics I have little expertise.  Nevertheless, I found troublingly narrow the discussion in Episode 5 of Soviet scientists who during the siege of Leningrad in the Second World War preserved the seed bank at Nikolai Ivanovich Vavilov’s plant industry institute. The show praised how these scientists preserved “several tons of edible material” even as 800,000 people starved to death in Leningrad—including the scientists themselves. Tyson ends the episode with the following:

“So why didn’t the botanists at the Institute eat a single grain of rice? Why didn’t they distribute the seeds and nuts and potatoes to the people of Leningrad who were dying of starvation every day for more than two years?

“Did you eat today? If the answer is yes, then you probably ate something that descended from the seeds that the botanists died to protect. They gave their lives for us. If only our future was as real and precious to us as it was to them.”

There was something not right, something kind of “creepy” (to borrow a favorite term of my students) about how the show breezed through that. Hey, those botanists didn’t just give their lives—they gave other people’s lives, too. To be sure, even several tons of seeds, nuts, and potatoes would not have prevented the starvation of 800,000 people; ten tons divided among 800,000 comes to a fraction of an ounce per person. Nevertheless, those scientists preserved foodstuffs amid starvation. I suspect that not everyone who was in Leningrad during the siege would have shared Cosmos’ generous view of these scientists.

This story brought to my mind a recent book called Why Fish Don’t Exist, by Lulu Miller. Miller explores the problematic side of what scientists will do in the name of science alone—what results when the voice of science tells us that people are really no different than ants, and there is no voice to say otherwise. Miller discusses one specific example of such results—eugenics, a prime example of science at its creepiest (and note, Miller is an atheist who essentially accepts that there indeed is no difference between ants and people, and so the book can be very dark and is not family fare). Cosmos might have benefited from having a voice like Miller’s to counterbalance that certain tone of science boosterism that appears in the telling of the Leningrad story. That might help keep the show out of the “creepy” zone.

Episode 6, “The Man of a Trillion Worlds,” does not have a “creepy” factor, but it does have other problems. Tyson tells the story of Gerard Kuiper, and how, in Kuiper’s youth, a century ago:

“Astronomers thought that the cosmos consisted of only a handful of planets, those of our own solar system. The great multitude of other stars were just barren points of light that had never given birth to worlds. We on Earth could still feel special. Our star system, the scientists told us, was the rarest of all, one blessed by worlds and moons.”

Tyson goes on to tell about Kuiper’s study of binary stars—two stars orbiting one another, something that astronomers had observed many times—and how this study led Kuiper to consider how the solar system formed:

“Kuiper asked himself, was our world, our moon and all the planets of our solar system nothing more than a failed binary star system? And if that’s how our solar system was created, had the same thing happened around other stars throughout the cosmos?... He was the first to envision the universe we now live in. Not a barren vastness meagerly dotted by childless stars, but one overflowing with possible worlds, countless planets and moons. In 1949, Kuiper astonished the world by declaring that our solar system was not so special after all, that every other star had its own family of worlds… But science wasn’t ready for that universe…”

But the fact is, by Kuiper’s time astronomers had been speculating about a “plurality of worlds” for centuries. There are oodles of examples of illustrations from past centuries of the sun and its planets being but one among countless stellar systems.

It is true that in the early 20th century the “plurality” idea was challenged. At that time the formation of Jupiter seemed to be a problem—Jupiter carries the bulk of the angular momentum in the solar system and no one could figure out a way to explain that momentum, if the solar system all formed together. So, in 1906, Forest Moulton, an astronomer, and Thomas Chamberlin, a geologist, theorized that the planets were the result of a near-collision between the sun and another star. The near-collision pulled out a stream of matter from the sun that eventually formed into the planets. Since stars are so far apart, that sort of near-collision would be incredibly rare. Therefore, our solar system would be incredibly rare. I have a book called Useful Science for High School (by Weed, Rexford, and Carroll), published in 1935, and on page 667 it says, “Astronomers have shown that it is probable that very, very few of the stars have planets.”

But the idea in common circulation was that stars have lots of planets. Consider Mark Twain’s Captain Stormfield’s Visit to Heaven, published right about the time the “near-collision” theory was being proposed. In it the Captain discovers a universe so busy with other worlds that almost no one in it knows anything about Earth. Earth turns out to be considered an utter backwater of a world. 

Twain wrote in a letter of 1909 about the inconsistency of the Genesis account, given that it describes God as taking several days to create the Earth, whereas “it took him only one day to make twenty million suns and eighty million planets!” Alfred Russell Wallace, who, along with Charles Darwin, developed the theory of evolution of life forms based on natural selection, published a work in 1904 against the idea of intelligent life on other worlds (owing to the improbability of evolution producing another version of human beings, he said) in which he groused about those who—

“...cannot accept my view that the unknown planets that may exist around other suns are also without intelligent inhabitants. They give no reason for this view other than the enormous number of suns that appear to be as favourably situated as our own, and the probability that many of them have planets as suitable as our earth for the development of human life.”

Wallace goes on to mention how these people think it ludicrous to suppose that intelligent life “has not been developed many times over in many of the worlds which they assume may exist”.

The idea of a plurality of worlds even was adopted by religious groups. Ellen G. White, a leader in the Seventh Day Adventist Church, wrote in 1913 of Earth as being the only planet to experience a Fall, and about how—

"It was the marvel of all the universe that Christ should humble himself to save fallen man. That he who had passed from star to star, from world to world, superintending all, by his providence supplying the needs of every order of being in his vast creation,—that he should consent to leave his glory and take upon himself human nature, was a mystery which the sinless intelligences of other worlds desired to understand."

And the idea of very, very few planets never broadly caught on. Consider Superman, the “strange visitor from another planet [Krypton].” He appeared just about the time my 1935 textbook was saying that very, very few of the stars have planets. Just a decade after Kuiper supposedly astonished the world, the whole SETI enterprise got started. In 1959, Giuseppe Cocconi and Philip Morrison published a paper in the journal Nature, “Searching for Interstellar Communications,” about using radio telescopes to listen for transmissions from planets orbiting other stars—and in 1960 Frank Drake made the first attempt to do just that.

The man from the doomed planet Krypton first appeared in Action Comics #1 in 1938.

In light of all this, does the idea in Cosmos—that Kuiper was the “first to envision the universe we now live in”; and that in 1949 he “astonished the world” by putting forth the idea that every other star had its own family of worlds; and that somehow science was not ready for this—make any sense? I was surprised to see this stuff, so contrary to the historical record, featured so prominently in an episode. I was struck by this in the same way as I was struck by Mario Livio’s recent Galileo book that was so problematic. Do these guys who invoke the history of astronomy in speaking to large popular audiences ever actually study the history? Or do they just run with tried and true old tropes?

Much in Episode 6 is good—about Carl Sagan and the benefits that result when scientists talk across disciplines and talk to the public—but there is a lot of trope, mostly regarding the idea that life on other worlds may be common. The show features lots of computer-animated footage based on Sagan’s knack for speculatively envisioning life in places that are not like Earth, like the atmosphere of Jupiter (where, in his mind, there might be city-sized cloud-floating jellyfish creatures). There could be life in those Jovian clouds, you know!

But the science that Tyson discusses at one moment goes against these tropes he uses at another. For example, Tyson tells how Sagan’s mentor Harold Urey—

“...wanted to know how life could have originated from lifeless matter. Working with another student of his, Stanley Miller, Urey designed an experiment to simulate the chemical conditions of the atmosphere on the early Earth. They wanted to see whether those basic chemicals could have led to amino acids, the building blocks of life. Could lightning have provided the spark that awakened matter into life?”

Since ancient times people have believed in “spontaneous generation” of life from lifeless matter. But science has shown all spontaneous generation theories to be wrong. The Urey-Miller experiment did not show how to awaken matter into life, and neither has any other experiment since. Getting life from non-life has so far been impossible, even on Earth where we know life happens. What scientific reason do we have for thinking life occurs in the inhospitable clouds of Jupiter?

Another example of the science Tyson discusses going against the tropes the show uses is his reporting on how—

“We’ve only been hunting for new worlds for a few decades, but we’ve already discovered many thousands of them.  We think some of them are hospitable to life and at least a dozen of them are earth-like.”

If we take “many thousands” to be at least four thousand, that is roughly one earth-like planet for every 300 planets discovered. Now, what does Tyson mean by “earth-like”? We can’t see these planets to know details about them; what we can do is determine their sizes and their distances from their stars. Tyson does not define “earth-like,” but he probably means “at the right distance from a star to possibly have liquid water, and of similar size to Earth.”

By these criteria our solar system has at least one “earth-like” planet, of course (Earth itself), but it may have as many as three (Venus, Earth, Mars). Thus, our solar system certainly has one earth-like planet for every 8 planets, and perhaps one for every 3 planets. Earth-like planets in our solar system are far more common than they are among the extra-solar systems we have discovered. As Mars and Venus show, a planet can be a lot like Earth, and still be nothing like Earth. Those dozen “earth-like” planets could be incredibly hostile to life.

Thus we are discovering a universe in which our solar system, and our planet, seem to be atypical places. After all, we are finding that even our sun is not so typical as we might once have thought, given that, as Tyson reports, “as many as 80% of all the stars in the cosmos may be red dwarfs”—stars much smaller, cooler, dimmer, and longer-lasting than our sun.

So the trope in Episode 6 is that of the bold scientist who is the first to envision the universe we now live in, who astonishes the world by putting forth an idea that others are not ready for, an idea that shows that we are not special, and so on and so forth. But that trope is not what science is telling us. Maybe someday we will find that the universe really is filled with a plurality of worlds like ours, but right now there is no evidence for the thousands upon thousands of “solar systems” featured at the conclusion of Episode 6:

“1,000 solar systems may be forming every single second.

That’s 1,000 new solar systems right there.

1,000 new solar systems.

1,000 new solar systems.

1,000 new solar systems.

1,000 new solar systems…”

New planetary systems, maybe, but new solar systems, that is, places like ours? Unlikely. Besides, the formation of a planetary system takes longer than all of human history multiplied many times over. The idea that in some given second, a new planetary system forms, or a thousand form, makes no sense. Why must Cosmos do this stuff?  Is not the science we know, and its history, cool enough as they are? Come on, Cosmos!

And so, O reader of Sacred Space Astronomy, you have my comments on the latest episodes of Cosmos: Possible Worlds. Keep in mind all my gripes are like the commentary of the die-hard fan who is up in the bleachers, screaming at the coach and the players of his favorite team for turning the ball over three times in a row, but who will be back for the next game, win or lose, probably screaming at the team again, rooting for them to actually play up to their potential.

Click here for all posts on “Cosmos: Possible Worlds”.

Cover Image: Bruce F Press, CC BY 3.0, via Wikimedia Commons

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