Letters to the Editor Humans Letters from the April 28, 2007, issue of Science News By Science News April 23, 2007 at 12:51 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print Long ago gas Finding CO2 levels that are 2,500 times higher in 5,000-year-old fulgurites than in modern samples, scientists have speculated that the extra CO2 resulted from vaporization of organic material by lightning (“Stroke of Good Fortune: A wealth of data from petrified lightning,” SN: 2/17/07, p.