It takes approximately 4.37 years for light to travel from Alpha Centauri to Earth.

Here's why:

* Distance: Alpha Centauri is the closest star system to our solar system, located about 4.37 light-years away.

* Light-year: A light-year is the distance light travels in one year.

* Speed of light: Light travels at a speed of approximately 299,792,458 meters per second (186,282 miles per second).

Therefore, light from Alpha Centauri takes 4.37 years to reach Earth, traveling at the speed of light.