Saturday, March 10, 2007


Conservapedia is a new invention of some conservatives as a balance to Wikipedia. A little background for those unfamiliar with the latest web technologies. Wikipedia is an online interactive encyclopedia. People all over the world can sign up for an account and submit entries. So if you look something up on Wikipedia it was very likely written by some expert in the field or someone very knowledgable of the field. It is therefore an excellent starting point for any number of research projects. According to many conservatives it, like reality, has a strong liberal bias, hence the creation of Conservapedia. Conservapedia has gotten a lot of derisive commentary, particularly on science and math blogs, as it's entries tend to lack something of the rigorous standards such folks expect. Indeed, nearly all the entries I've seen are simply awful. I was leaving it to others to comment on this monstrosity but I just has to go look for myself and check out something that is hardly a major controversy and about which I know something, the Hubble Space Telescope. Here is the entire entry:

The Hubble Telescope was an American space probe that explored distant space beginning in 1990.

It included one of the biggest engineering mistakes ever when its telescopic lens was mistakenly placed backwards on top of other lens, thereby reducing the clarity of the images. In a space mission, astronauts were able to add a corrective lens to it which restored it to its intended performance.

The telescope is named after astronomer Edwin Hubble whose observations of galaxies led him to the discovery that the universe is expanding.
That's it. Now in the first place the Hubble is still operating and NASA plans another servicing mission next year. The use of the past tense is a bit premature. The mirror was not put in backward, that error would have been quite uncorrectable. Rather the mirror was installed just fine, but was manufactured to be a few microns (that is thousandths of a millimeter) off of design at the edges of the 2.4 meter disk. That error, small though it may sound, was far more than the manufacturing process should have allowed and was sufficient to greatly reduce the quality of the images. I'm not sure what the author is talking about and whether the actual explaination makes NASA look better or worse, but his entry is just wrong. Also, to categorize this as "one of the biggest engineering mistakes ever" is a bit absurd. It is a matter of opinion, so I can't prove it wrong, but really I think I can come up with about a hundred engineering mistakes that were much worse than this. The final paragraph is fine.

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