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.
Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
Vredefort crater, or dome, is the largest verified impact crater on earth, and can be found around the town of Vredefort in the Free State Province of South Africa. The asteroid that hit Vredefort is estimated to be the largest to hit earth in the last 4 billion years, and was over 15km (9.3mi) in diameter. The resulting crater is just over 300km (186.4mi) in diameter, and its huge size has earned it a title as a world heritage site.