As strange as that assertion may seem to humans accustomed to traveling a mere 70 miles per hour on the highway, it makes a lot of sense on a cosmic scale. Consider this: If the observable Universe was reduced to the size of planet Earth, traversing the Milky Way Galaxy would be roughly equivalent to walking three houses down the block to visit your neighbor. And yet, traveling at the cosmic speed limit of our smaller, Earth-size universe, that short jaunt would take 100,000 years!
This example showcases just how tediously slow exploring the galaxy would be for a ship traveling at the speed of light. Such a journey would span more than a hundred human generations!
Even if you don’t consider humanity’s self-centered wish for interstellar light-speed travel and instead think about photons dashing across our solar system, the speed of light still seems positively sluggish. As astrophysicist Brian Koberlein calculated, it takes 45 minutes for light from the Sun to reach Jupiter, and five hours for it to reach Pluto.