"Swimming" in space-time On the main forums page, there is a link in the "Scientific American" section to an article http://www.scientificamerican.com/article.cfm?id=surprises-from-general-relativity". I've had a look at the article and I don't even begin to believe it. Even if you forgive the illustrative device of macroscopically-curved space, the idea that one could wriggle around in a way which escapes conservation laws seems extremely far-fetched. Even his simplified example of "swimming" on an ordinary sphere seems to be in obvious violation of conservation laws. I checked the article date and it's not April 1. Does anyone think this could REALLY be correct? (I'd go so far as to say that if GR really did work like that, I'd count it as evidence of a problem in GR).