Careful with Those Fractions

(Eugene Volokh)

A very interesting Wall Street Journal piece on the supposedly speed-limit-busting neutrinos included this sentence:

Physicists fired a beam of neutrinos (exotic, ghost-like particles that can penetrate even the densest of materials) from Switzerland to Italy, over a distance of 454 miles. Much to their amazement, after analyzing 15,000 neutrinos, they found that they traveled faster than the speed of light — one 60-billionth of a second faster, to be precise. In a billionth of a second, a beam of light travels about one foot. So a difference of 60 feet was quite astonishing.

But as Ed Whelan (National Review Online) points out, a distance of 60 feet would be traversed by light in 60 billionths of a second, not in one 60-billionth. (This story confirms this, and the author of the newspaper article confirmed it, too.) The neutrinos arrived 60 billionths of a second faster, rather than traveling one 60-billionth of a second faster. Just a reminder to be careful about what one reads, whether about math, physics, law, or anything else, and whether in newspapers or on this blog.