Toothed whales range in size from dolphins, porpoises, and orcas to sperm whales (at almost 60 feet long and 45 tons). There are about 65 species of toothed whales in the world.
Toothed whales are hunters, unlike the baleen whales that filter food through the baleen plates in their mouths. Also, toothed whales have one blowhole, while baleen whales have two.
Black holes are places where ordinary gravity has become so extreme that it overwhelms all other forces in the universe. Once inside, nothing can escape a black hole's gravity — not even light.
How can we find something that's essentially invisible? And how close is the closest black hole? Take this voyage to a black hole to get those answers and more.
It would run 1,179 miles from Canada to Nebraska, but the proposed Keystone XL pipeline also sits in the middle of a big debate. Those in favor of building it claim its many benefits, but environmentalists opposing it cry foul.
Examine the facts about jobs, spills, climate change, and gasoline prices about this controversial project.
Winter's cold can make life difficult for many animals. Think about it: You wouldn't want to have to find your dinner under a foot of snow.
Some animals migrate to warmer regions, but others do something different. They hibernate. They find a snug place, stock up on food, and take a very long nap.