Exploring the Moon's Silent Craters

High above the Earth, a small robotic rover rolls slowly across the gray, powdery dust of the Moon. Its rugged metal wheels turn steadily, leaving tracks as it approaches the rim of a deep crater. Many lunar craters are large bowl-shaped pits formed when space rocks crashed into the surface. Some are billions of years old. By studying these ancient holes, scientists can learn what the Moon is made of and uncover clues about the history of our solar system.

Driving across the Moon is very different from driving on Earth. One of the biggest differences is the complete silence. On Earth, sound moves through the air as invisible waves of vibrating particles. When a car drives by or rocks crunch underfoot, those vibrations travel to our ears. The Moon, however, has almost no atmosphere. Because there is virtually no air to carry sound waves, sound cannot travel through the open space above the surface as it does through air on Earth. Even when the rover's heavy wheels grind against sharp stones, no sound can be heard across the empty landscape.

Instead of listening, the rover relies on specialized equipment to do its work. High-definition cameras on a tall mast scan the ground ahead, helping mission controllers on Earth steer the machine away from dangerous boulders and steep drops. Solar panels on top of the rover soak up sunlight to power its internal computer and rechargeable batteries.

When the rover reaches the edge of a crater, it pauses to investigate. A long robotic arm unfolds and lowers a sensor onto a jagged lunar rock. The sensor shines a beam of light to identify the minerals inside the stone, while a close-up camera snaps detailed pictures. After collecting its data, the rover beams the information across space to scientists on Earth, continuing its quiet exploration of another world.