The expression "3 × 10^8" represents a number in scientific notation, which is a way to simplify very large or very small numbers. In this case, it means 3 multiplied by 10 raised to the power of 8. This results in the number 300,000,000, which is often used to describe the speed of light in a vacuum, approximately 299,792,458 meters per second. Using scientific notation makes it easier to work with such large numbers, especially in fields like physics and astronomy. For example, when discussing distances in space, like the distance from Earth to the Sun, using "3 × 10^8" helps convey the vastness of the universe without writing out all the zeros.