The Science Behind It All

How far, how fast?

Radio waves travel at the speed of light. So your messages beamed into space will have travelled 186,000 miles after the first second of being transmitted. Within two seconds a message will have passed by the orbit of the Moon. It's been said that nothing travels faster than bad news. Well, radio waves are one of the few things that do!

electro magnetic spectrum

Radio Astronomers use radio telescopes to determine the nature of objects in the Universe that cannot be determined by viewing light from those objects alone. Using these signals, astronomers are able to receive and analyze signals from sources that are billions of light years from Earth. That means that some of the signals received were first emmitted into space billions of years ago, before the Earth was even formed!

Note the illustration of the electromagnetic spectrum above. Much of it is absorbed or filtered out by the Earth's atmosphere. But the lower end of the radio wave spectrum has a clear shot down to Earth and conversely, signals generated at those frequencies make it out into space with relatively little degredation. That's the sweet spot chosen by SpaceSpeak to beam messages into the cosmos.

Though a radio signal decreases in intensity as it spreads outward with time, there is practically no theoretical limit to how long a radio signal can travel. Your messages will continue to travel through space long after Earth is consumed by her dying Sun. Now that's how to leave your mark on the Universe!


Scientists have been scouring radio signals for signs of life on other planets for years. The Search for ExtraTerrestrial Intelligence (SETI) analyzes huge quantities of data obtained from radio telescopes around the world looking for signs of a radio signal created by an advanced civilization.

If Humans thought to do this then surely some scrappy species a few hundred light-years away could do the same. In their search for extraterrestrial intelligence they might just come across your message. Make it count!