Thunderstorms with lightning do happen more often when air temps are warm, but it's possible to see lightning in cold weather, too - even during a snowstorm.
The U.S. has the resources to meet an increasing global need for rare earth elements - elements used in high-tech products and technologies for alternative energy - according to Keith Long.
Only about 3,200 tigers remain in the wild. John Seidensticker predict that, without international intervention, wild tigers will go extinct by the year 2022.
A research team (Stephen Giovannoni) has discovered life deeper in the Earth's crust than ever before, a mile below the ocean floor in the North Atlantic.