Attempts to contact aliens date back 150 years
The desire to contact intelligent life on other planets is much older than the UFO craze and the SETI movement. Several 19th century scientists contemplated how we might communicate with possible Martians and Venusians.
These early proposals - which predate by 150 years the first extraterrestrial message that was sent in 1974 - were based on visual signals, as the invention of radio was still decades away.
In fact, as history shows, ideas for interplanetary communication have largely been driven by whatever the current technology allowed - be it lamps, radios or lasers.
"You go with what you know," said Steven Dick, NASA Chief Historian.
Over two thousand years ago, the ancient Greeks argued over the existence of life on other planets, but the idea really took off after the Copernican revolution.
"Once it was realized that all the planets go around the sun, it was not hard to imagine that the other planets could be like Earth," Dick said.
Galileo, Kepler and others considered the inhabitability of the planets, while being careful not to upset Church authority.
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These early proposals - which predate by 150 years the first extraterrestrial message that was sent in 1974 - were based on visual signals, as the invention of radio was still decades away.
In fact, as history shows, ideas for interplanetary communication have largely been driven by whatever the current technology allowed - be it lamps, radios or lasers.
"You go with what you know," said Steven Dick, NASA Chief Historian.
Over two thousand years ago, the ancient Greeks argued over the existence of life on other planets, but the idea really took off after the Copernican revolution.
"Once it was realized that all the planets go around the sun, it was not hard to imagine that the other planets could be like Earth," Dick said.
Galileo, Kepler and others considered the inhabitability of the planets, while being careful not to upset Church authority.