Ben Shelton ranked a career-high 10th in the ATP Tour world rankings released Monday, giving the United States three men in the top 10 for the first time in nearly two decades.

In commercial ATP monitoring kits, instructions suggest taking swabs on surfaces of known quality to establish baseline levels of bioluminescence 12, 13.

But life also generates its own light—and not just the bioluminescence of glowworms and lamp-headed anglerfish or the radiation produced by heat.