The common name for the outer layer of the Earth's atmosphere is the "exosphere." This layer is the uppermost part of the atmosphere, extending from about 600 kilometers (373 miles) above the Earth's surface to around 10,000 kilometers (6,200 miles). The exosphere is characterized by extremely low densities of particles and very thin air, making it almost a vacuum. It is where satellites orbit the Earth and where the atmosphere transitions into outer space. Due to its height, the exosphere contains satellites and space debris, and it plays a vital role in telecommunications and global positioning systems.