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.
We know that the Earth has been hit by some very large asteroids that have barely registered as life destroyers. Impacts on the scale of the dinosaur killer are rare. The Manicouagan crater in Canada-one of the largest impact craters on the planet-was created in a destructive impact about 215 million years ago.