Interplanetary dust — a combination of debris from ancient asteroid collisions, active comets, and interstellar dust — is pervasive throughout the solar system. Roughly 220,000 pounds (100,000 kilograms) of space dust fall onto Earth every day. And in interplanetary space, streams of cosmic dust can travel together at speeds of up to 44 miles per second (70 kilometers per second).
The researchers found that as these streams of dust graze Earth, they collide with organic particles found in the upper atmosphere. These small particles, which are trapped about 93 miles (150 km) or higher in Earth’s atmosphere, are then knocked out with enough force to escape Earth’s gravity altogether. Once the particles are free from the bounds of Earth, the powerful dust flows can pick up and carry the microscopic hitchhikers off through interplanetary space.