Here’s an interesting question—at what distance can the human eye detect a candle flame?
Put this conundrum to Google and the first answer says it is possible to see a candle flickering up to 48 kilometers (30 miles) away, considerably further than the horizon. Can that be true?
Today, Kevin Krisciunas and Don Carona at Texas A&M University in College Station put this question to the test. And the answer is considerably less than the web would have us believe.
Image: http://www.technologyreview.com
