Earth is the fourth-smallest of the planets—though, in terms of the rocky planets, it's the largest—but it's the densest. Jupiter is the largest planet in the solar system, but it's Saturn—the solar system's second-largest planet—that takes the prize for least dense.
More than 20 percent of the world's oxygen is produced in the Amazon Rainforest. More than half of the world's estimated 10 million species of plants, animals, and insects live in the tropical rainforests.
Jimmie Luecke, a cattle farmer in Texas, created the world's biggest signature in the 1990s. Also, it is useful for analyzing NASA's satellite imagery.
Earth is the only place in the Solar System where water can be present in its three states: solid, liquid, and vapor.
In April 1970, the crew of NASA's Apollo 13 mission swung around the far side of the moon at an altitude of 158 miles (254 km), putting them 248,655 miles (400,171 km) away from Earth.