Monday, November 2, 2015

Have We Discovered a Dyson Sphere Under Construction?

Many of you have probably seen this article over at The Atlantic.  The basic story is that the Kepler mission, which is designed to look for planets orbiting other stars, has turned up something very strange.  And no one is exactly sure what it is.

The Kepler mission looks for planets by measuring the brightness of various stars in our galaxy. When a planet orbiting a star passes between the star and us, the star looks slightly dimmer.  It's basically a miniature solar eclipse, except that it's not our sun that's being eclipsed by the moon, but a distant star being eclipsed by its own orbiting planet. Astronomy is a messy business, so there are plenty of other things that can cause a star to get dimmer and then brighten up again. Some stars just do that on their own -- they're called variable stars. Sometimes there's a disk of dust orbiting a star -- that's very common. So astronomers have to go to great pains to be able to distinguish planets from these other types of objects.

And the problem is that this rather mysterious star, described in this paper doesn't really fit any of these scenarios.  Its light output varies in a strange way, but it's not consistent with a planetary system.  A disk of dust is ruled out by the lack of infrared light.  So a few people are starting to mutter darkly about the possibility of extraterrestrials....  To be fair, there's nothing at all about space aliens in the actual scientific paper, as you'll see if you look at it.  But scientists have long postulated that an advanced civilization would want to trap the energy coming from its star more efficiently. Freeman Dyson proposed that aliens might build a spherical shell around their star -- a Dyson sphere.

The most famous use of this idea in science fiction is not a sphere at all -- it's a gigantic orbiting ring --- Larry Niven's Ringworld, from the novel of the same name.

So have astronomers discovered a Dyson sphere under construction, or some other evidence of alien builders? I doubt it. The universe is full of strange phenomena, and each time we discover a new one, theorists are quick to come up with an explanation.  For instance, when pulsars were first discovered, it seemed possible that aliens were producing these very regular radio bursts. But now we think that they are really just rapidly rotating neutron stars.

Having said that, I do know that scientists are now proposing to look for anomalous radio emissions from this star. So it's starting to feel like we're in the middle of a bad science fiction movie about alien invaders. And what role do you and I play?  We're the extras in the movie.  And you know what happens to the extras in all alien invasion movies....

9 comments:

Peter Denton said...
This comment has been removed by the author.
Peter Denton said...

Something I remember from when Freeman Dyson visited was that he is usually the first to point out that Dyson sphere's first came from Olaf Stapledon's Star Maker more than twenty years before Dyson wrote on the same concept from a more scientific point.

Robert Scherrer said...

Ironically, it's the thing Freeman Dyson is most famous for.

Kathy said...

I'm not yet quite at the point that I will dismiss any science story in the popular media without looking at it, but I do keep two quotations firmly in mind:

1) "The Universe isn't stranger than we imagine, it's stranger than we can imagine." J.B.S. Haldane

2) "The most exciting exclamation pertaining to scientific discovery is not 'Eureka!' but rather 'Now, that's funny.' " Isaac Asimov

Robert Scherrer said...

The Asimov quote is a particularly accurate description of how scientific progress usually comes about.

Anonymous said...

I'm working on a paper about Christopher Clavius, an astronomer from the generation before Galileo, and his philosophy of science, and I'd like to use the Asimov quote (I'm a fan of his as well). Could someone point me to the source? The mighty Google only brings up this blog in a search.


Chris Kirk Speaks

Robert Scherrer said...

Which Asimov quote?

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