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.
Olympus Mons, the largest volcano on Mars, is so big that it can be seen with many common backyard telescopes. The largest active volcano on Earth is Mauna Loa in Hawaii, which has erupted off and on for the past 700,000 years. But it is about 2,000 square miles in size, a tiny fraction of Tamu Massif.