Rosa Parks sparks Civil Rights Movement. On this day in 1955, Rosa Parks, an African-American, was arrested and charged with violating a Montgomery, Ala., ordinance that required her to relinquish her bus seat to a white passenger. Her act of defiance sparked a yearlong bus boycott in the segregated city.
View full size image. The speed of light in a vacuum is 186,282 miles per second (299,792 kilometers per second), and in theory nothing can travel faster than light. In miles per hour, light speed is, well, a lot: about 670,616,629 mph. If you could travel at the speed of light, you could go around the Earth 7.5 times in one second.
Trouble is, traveling close to the speed of light brings about other effects, too. In Natural Science, Edelstein and Edelstein point out that hydrogen in any craft cable of traveling at the speed of light would also prevent it from traveling at the speed of light.