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.
2. Chicxulub. The Chicxulub crater is 112 miles wide, about the distance from Los Angeles to San Diego, and is now underneath the Yucatan peninsula in Mexico. According to scientists, the asteroid hit Earth 65 million years ago, thought to be a hint on what caused the mass extinction of the dinosaurs. (NASA). 3. Sudbury. The Sudbury Crater, in Ontario, Canada, is believed to been formed by a meteor blast over a billion years ago.