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The Loss of Centrality
In this interval of blessed tranquility between the titanic struggle to choose the next president of the “world’s greatest nation” (same guy as last time), and the world-shaking choice of the next leader of the “Middle Kingdom” (Xi Jinping, but it’s still officially secret for a few more days), a delicious moment of sheer silliness. The British Broadcasting Corporation has banned a science program because it might trigger an interstellar invasion.
They would not normally ban a program made by Brian Cox. He is a jewel in the BBC’s crown: a particle physicist with rock-star appeal – he played in two semi-professional bands, and in the right light he looks like a younger Steven Tyler – who can also communicate with ordinary human beings. They just forbade him to make the episode of “Stargazing Live” in which he planned to send a message to the aliens.
Cox wanted to point the Jodrell Bank radio telescope at a recently discovered planet circling another star, in the hope of making contact with an alien civilization. The BBC executives refused to let him do it, on the grounds that since no one knew what might happen, it could be in breach of “health and safety” guidelines.
Cox, a serious scientist, knew exactly what would happen: nothing. Even if there are hostile aliens out there, space is so vast that light from the nearest star, traveling at 300,000 kilometers per second (186,000 miles/sec.), takes four years to reach us. He was just doing his bit in the centuries-long scientific campaign to convince people that they are not at the centre of everything.
The BBC “suits”, who do think that they are at the center of everything, weren’t having any of that. If there are aliens out there, and they find out we are here, their first reaction will probably be to come here and eat our children. And then the BBC will get blamed for it. Sorry, Brian. Drop the radio telescope and step away from it slowly.
The suits richly deserve the derision that has come their way, but if there really is life elsewhere, and even perhaps intelligent life, then we aren’t at the center of anything any more. We are, as Douglas Adams once put it in The Hitch-Hiker’s Guide to the Galaxy, “far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy.”
We used to believe that the whole universe literally revolved around us. Then came Copernicus. But we went on believing that we are very special. We look like other animals, but we are so special that we don’t cease to exist when we die. We give the universe meaning just by being alive
A bit at the time, however, science has been destroying all of our traditional ideas about our own centrality. And here comes another blow.
In a universe with trillions of stars, it was always less presumptuous to assume that we are not unique than to insist that we are. But just twenty years ago there was no evidence to show that other stars actually do have planets, let alone that some of those planets harbor life.
We now know of the existence of some 800 “exoplanets”, and the number is doubling every year or so. Most of these planets are gas giants like Jupiter or Saturn, not at all like Earth, simply because the giants are easier to detect. But what we have really been looking for is planets like our own. We KNOW that life thrives here.
The astronomers at the European Southern Observatory in Chile have now found such a planet. It is called HD 40307g, and it orbits a small orange-colored sun 42 light-years from here. The planet is rocky, like Earth, and it orbits its star at a distance where the temperature allows water to exist as a liquid. It is certainly a candidate for life.
In the past decade we have learned that most stars have planets, and that they typically have lots of them. HD 40307 has six planets orbiting at different distances, at least one of which (HD40307g) is in the “Goldilocks” zone.
There are between 200 billion and 400 billion stars in our home galaxy, the Milky Way, and probably at least as many planets. If only one in a hundred of those planets harbors life, which is likely to be an underestimate, then there are two billion living planets. We are not unique and special. We are as common as dirt.
Douglas Adams also wrote: “If life is going to exist in a Universe of this size, then the one thing it cannot afford to have is a sense of proportion.” But we are gradually acquiring exactly that, and it doesn’t really hurt. It is possible to be aware of your own cosmic insignificance and still love your children. Even though they are without significance too.