Disappearing Planets in the News: Cautionary Tale

With science, not to mention Science!, there’s finding stuff and then there’s finding stuff. For example, today we learn that a tiny hedgehog and a personal-size tapir lived in British Columbia millions of years ago. The researches discovered physical remains of the two creatures, although in the case of the hedgehog, they used CAT scans to construct a 3-D model of the jawbone while it was still embedded in rock – they didn’t think it could be safely removed. So, they had parts of the tapir skeleton in hand, and images of the tiny hedgehog jawbone that was too small to extract from the rock.

And that’s the kind of evidence we get for the existence of extinct animal species from paleontologists. From there, we usually descend rapidly into more or less baseless speculation about appearance (‘artist’s rendition’) or behavior (looks like a hedgehog; hedgehogs eat bugs; probably ate bugs) which is fine, as far as it goes, but we should always keep separate, in our minds, actual physical evidence from speculation, no matter how reasonable such speculation may seem.

Careful about those alien planets, especially if your fashion sense runs toward the more rosy end of the spectrum.

Today’s example: a few years ago, two ‘earth-like’ planets were ‘discovered’ orbiting a near-by star. Well, by discovered we mean: certain observed fluctuations in the star’s spectrum could be explained, under certain theories, by the presence of two rocky planets of certain masses orbiting a certain close distances. It’s all a bit messy: there’s a lot background noise when looking at spectra, and it’s all very far away, and we’ve got to filter out the mess without filtering out the data, and, even then, we have some theories and models that allow us to back into the existence of invisible planets, and to construct very broad models of what those planets might be like.

And there’s nothing wrong with this, in fact, it’s very proper and exciting. Only problem is when we switch from thinking ‘tantalizing evidence’ to thinking ‘almost certainly true’ to ‘established fact’ without actually establishing a fact.

So, today, we learn that those fluctuation in the stellar spectrum are more easily explained some other way – not as planets. The astronomers have refined their methods and theories, and concluded that when all the natural variations that could be expected from such a star were filtered out, the evidence for these two planets disappeared. So, oops.

But, the news is generally good: under the refined method, stronger evidence for the three other planets that are claimed to be orbiting that same star – outside the ‘Goldilocks zone’ so not as interesting to SETI fanboys – was obtained, strengthening the overall claims of this planet-hunting method. So, we lost a couple planets, but we gained a better approach to finding planets in the future.

Nonetheless – some snapshots would be nice, maybe of the surface. Until then, there’s always going to remain some uncertainty as an unavoidable feature of using surrogate measures in lieu of direct observation.


Author: Joseph Moore

Enough with the smarty-pants Dante quote. Just some opinionated blogger dude.

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