Continuous positive airway pressure (CPAP) machines are used to maintain an open airway in patients diagnosed with obstructive sleep apnea. The machine functions by blowing pressurized air into the airway via mask at a setting determined by sleep study and prescribed by a physician.
Only around 180 impact craters have ever been discovered on Earth and around 30 per cent of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded.
The largest crater on the moon is on the side we cannot see, and is named the South Pole - Aitken Basin. It is 2240km in width, and 13 kms deep. This is also the largest known crater in our solar system. The largest crater visible to us is the Bailly crater, which is 26 000 square miles in size.