Tuesday, October 25, 2011
Fastest man-made thing on Earth
The X-15 is the fastest manned aircraft in the world which can reach Mach 6.72 or 5,115 mph.
light is now known to travel at 299,792,458 metres per second (light particles called photons)
The circumference of the Earth at the equator is 25,000 miles. The Earth rotates in about 24 hours. Therefore, if you were to hang above the surface of the Earth at the equator without moving, you would see 25,000 miles pass by in 24 hours, at a speed of 25000/24 or just over 1000 miles per hour.