Saturday, March 14, 2009

Happy birthday, Giovanni Schiaparelli: Observer of Canali on Mars

Happy birthday, Giovanni Schiaparelli.

He's the Italian astronomer who observed channels on Mars in 1877. Being Italian, he wrote that he had observed channels: "canali" in the Italian language. Someone translated Schiaparelli's notes into English, and decided that "canals" was what "canali" means.

Percival Lowell, American Astronomer, read Schiaparelli's notes, as (mis-) translated, and saw canals on Mars. Lots of them.

Pretty soon, just about everybody with a telescope was seeing canals on Mars, which proves that there must be Martians to build the canals. Or that there were, until very recently.

Edgar Rice Burroughs wrote quite a few books about Barsoom - but I'm getting off topic.

Don't be too hard on Lowell and company: An engineering megaproject of the day, the Suez Canal, had been completed 1869. People were thinking "canals," pretty much the way we're thinking "hybrid" and "digital" today.

One more thing: Yes, Giovanni Schiaparelli was color blind. Which may not have had much to do with his seeing channels that weren't there.

Mars, seen from Earth, particularly if you're using an 8.75-inch telescope (0.2 meters), is a small, shaky, roundish thing with indistinct markings.

Before astronomers could send robot observatories into space, they had to look at the universe through Earth's atmosphere: which is very good at keeping us alive, but far from optically perfect.

So in the good old days, astronomers might wait for moments of good seeing, and sketch what they saw.

We've learned quite a bit about the human brain's visual system lately: we're really good at pulling patterns out of visual data that has a great deal of noise. Sometimes, the patterns are actually there. Sometimes, as was the case with Mars, they're not.

Credit and Copyright: Tom Ruen, Eugene Antoniadi, Lowell Hess, Roy A. Gallant, HST, NASA

Or, rather, aren't quite there. When maps of Mars, based on eyeball-on-Earth observations, are compared to maps based on photos and other data from survey ships, there's a pretty good match between the major "Schiaparelli" features, and patterns of dark and light material on Mars. What's missing are the neat, straight, lines that our brains used to 'connect the dots.'

Credit and Copyright: Tom Ruen, Eugene Antoniadi, Lowell Hess, Roy A. Gallant, HST, NASA

More about Giovanni Schiaparelli, Mars, and all that:
Mars Maps and Resources:


(ABSABS: The SAO/NASA Astrophysics Data System. "The SAO/NASA Astrophysics Data System (ADS) is a Digital Library portal for researchers in Astronomy and Physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 7.5 million records: Astronomy and Astrophysics, Physics, and arXiv e-prints. The main body of data in the ADS consists of bibliographic records, which are searchable through highly customizable query forms, and full-text scans of much of the astronomical literature which can be browsed or searched via our full-text search interface. Integrated in its databases, the ADS provides access and pointers to a wealth of external resources, including electronic articles, data catalogs and archives. We currently have links to over 8.1 million records maintained by our collaborators."

Cool, huh?

Other posts, about "Mars, Mostly."

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