Optimists point out that we have another weapon in our space arsenal—the radio messages we’ve been transmitting from Earth for many years. Though we can’t get far enough physically to penetrate even the fringe of space, at least we can communicate with any intelligent life that might be out there. After all, radio waves travel at the speed of light—186,000 miles per second, nearly 670,000,000 miles per hour—twice as far in 60 minutes as the Pioneer craft go in a year. That’s fast!