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.
Nature of Light. Light is a wave, but the traveling disturbance is and electric and magnetic field, not a pressure variation like a sound wave. Sound has to travel through matter, but light does not have to travel through a medium. Therefore light can travel through a vacuum. Light waves also carry energy with them; that is how sunlight warms us up when we absorb it. In a vacuum, light travels with a speed of about 3Â´108 m/s, or 300,000,000m/s, i.e. very fast.