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.
The hotter an object gets, the more photons it gives out. Light travels as a wave. But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuumâa completely airless space. (Sound, on the other hand, must travel through a solid, a liquid, or a gas.) Nothing travels faster than light energy. It speeds through the vacuum of space at 186,400 miles (300,000 km) per second.