Date: October 28th, 2012

Title: Encore: The Moon of Venus

Podcaster: Ben Lillie

Organization: The Story Collider, storycollider.org

This podcast originally aired onAugust 23rd, 2010
http://365daysofastronomy.org/2010/08/23/august-23rd-the-moon-of-venus/

Description: Two tales of science done right and done wrong, starring Nicola Tesla and Giovanni Cassini.

Bio: Ben Lillie is a physicist who left the ivory tower for the wilds of New York’s theater district. How now writes and produces shows about science. He is a Moth StorySLAM winner, and hosts the monthly science storytelling show, The Story Collider, where guest are invited to share true, personal stories of the times in their lives when science has been important, inspiring, or simply absurd. He likes to say that life is different now, largely because it is. He has also earned 27 badges as a member of the Order of the Science Scouts of Exemplary Repute and Above Average Physique, which is 24 more than than the number of badges he earned as a Cub Scout.

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Transcript:

I’ve been reading his collected letters of Nicola Tesla (because I do things like that), and one in particular caught my eye. Tesla, for those who don’t know, was a brilliant inventor, he created the alternating current generator — which made possible our entire electrical infrastructure, invented the radio, and many other things. In 1908, he wrote a lot of letters to the editors of The World (a newspaper) explaining his predictions for the following year. Here they are:

1) That people will realize that the electromagnetic force does not diminish with distance. That is, that the inverse square law is fine.

2) That radium does not exist, and radioactivity is electromagnetic and emitted by all things.

3) That airplanes will be replaced by the much more efficient and workable dirigibles.

4) That the propeller will be replaced by a new mode of ship propultion.

It’s funny how one person, who was so often brilliant, could also be so wrong.

I found a nice contrast to this in a neat book I stumbled on. It’s called Myths and Marvels of Astronomy, by Richard Anthony Proctor. It was written in 1896, over a hundred years ago. It has sections on the wonders of astronomy, but also the misuse, and the later sections are eerily familiar. The first one is on Astrology, and some of the passages could have come from many of the blogs, “Divination by the stars holds no higher position than palmistry, fortune-telling by cards, or the indications of the future which foolish persons find in dreams, tea-dregs, salt-spilling, and other absurdities.”

But the story that I found most interesting was the discussion of Cassini, the great astronomer who discovered the first four moons of Saturn, and the great red spot on Jupiter. The book recounts how Cassini also discovered Nieth, the moon of Venus in 1672, and how that discovery was confirmed by repeated observation over the next century.

And as I said, this story is a nice contrast to Tesla’s wildly wrong ideas. Cassini observed it twice, once in 1672, and again in 1686. It was seen again in the mid 1700s by a range of astronomers. There were other astronomers, including the great William Herschel, who couldn’t find the moon, and doubted it’s existence.

But it’s existence was confirmed spectacularly in 1761 when two astronomers, one skeptical of the discovery and one who hadn’t heard of it, both observed the moon, and another specifically looked for it during a transit of Venus across the Sun. Several observed it to be a crescent, in the same phase as Venus, which is exactly how a moon should look.

This is a wonderfully textbook example of scientific discovery. Someone sees something, there’s a question of whether it’s true, and then there are repeated tests and confirmations. Tesla just guessed — because he liked dirigibles more than airplanes — and lo and behold, he was wrong.

Now, if you’re wondering why you’ve never heard of the moon of Venus before, that’s because it does not, in fact, exist, which makes the discovery even more remarkable.

By the mid 1800s many more observers were failing to find the moon, and it was becoming clear that it wasn’t there. No one is exactly sure what happened, and why so many people thought they saw it. It’s probably that it was a collection of factors, from lens aberrations in the telescopes they were using at the time, to accidental conjunctions with background stars, to them wanting to see it, since the great Cassini himself had discovered it.

It’s also worth remembering that all of this was in the context of the discovery of the moons of Jupiter and Saturn, as well as the discovery of Neptune, Uranus, various comets, asteroids, and the growing realization that the solar system was a rich and messy place. It was perfectly reasonable that Venus would also have a moon.

I’m not sure what the lesson is here. That even the greatest scientists can be wrong? I think; I hope, we knew that. That even if we follow all the “rules” we sometimes get the wrong answer? But, at some level, that’s what science is. Being wrong and then checking and fixing until we’re not wrong. And then checking again.

In that same book, Myths and Marvels of Astronomy, Richard Proctor goes on to say that “It has been gravely suggested… that Venus has a surface of metallic brilliancy, with a vitreous atmosphere,– which can only be understood to signify a glass case.” He goes on to say that he doesn’t think it likely that that is correct (and of course, it isn’t), but I think that’s wonderful that he put it in. In the middle of a discussion of how great astronomers were deceived, he inserts a paragraph about a current wild speculation, that could well turn out to be false.

I said I thought this story was a great contrast to Tesla, and I do. Not because they got the answer right, but that they got it wrong for the right reasons. That said, I do wish he’d been right about the dirigibles.

End of podcast:

365 Days of Astronomy
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