One image can change the world. In 1969, the sight of Ohio’s savagely polluted Cuyahoga river catching fire helped galvanize an environmental movement. Filmmaker Josh Fox, creator of “Gasland” (7 p.m., HBO) hopes scenes of flaming faucets will do the same thing.

A native of Milanville, Pa., located above the gas-rich shale deposits, Fox was offered more than $100,000 to drill on his property. He was intrigued until he began hearing tales of poisoned wells in the towns where drilling had already taken place.

Armed with a camera and curiosity, he discovered stories of poisoned wells in areas where gas companies had been drilling by hydraulic fracturing. Known as “fracking,” the practice uses a cocktail of chemicals to blast open shale located miles beneath the surface.

The most startling images come when he visits homes in Colorado where folks light a match to a running tap and set off an explosion in their kitchen sinks. He also documents poisoned creeks where gas bubbles to the surface. Light a match to those streams, and they explode, too.

In several instances, he meets with gas-company spokespeople who assure him that the process is safe. But when he offers them a glass of tap water, they refuse. And in many places, drillers have agreed to provide homeowners with an alternative water source, while refusing to admit that they have poisoned any wells.

“Gasland” could not be more timely as the crisis in the Gulf of Mexico shows what happens when the federal government allows energy companies to run amok.

• The eighth season of “History Detectives” (8 p.m., PBS, check local listings) begins with three space-related mysteries.

Tonight’s other highlights

• A fetching widow stands trial on “Lie to Me” (7 p.m., Fox).

• “Behind the Music” (7 p.m., VH1) profiles Courtney Love.

• Amy leaves John on “The Secret Life of the American Teenager” (8 p.m., Family).

• Poisoned dogs lead to bigger fish on “Good Guys” (8 p.m., Fox).

• A visiting helicopter brings more mysteries on “Persons Unknown” (9 p.m., NBC).

• A changed Grace returns to Oklahoma City on the series finale of “Saving Grace” (9 p.m., TNT).