“Only nascent civilizations will transmit messages without compression, since compressionless transmission is such a bad use of bandwidth. Compressed transmissions, though, have the problem that they approach randomness. That means that the only thing SETI can recognize will be either intentional communications or else the communication of very early civilizations, pre-compression. The situation featured in Contact, where a civilization notices the ‘momentary’ event of our world broadcasting uncompressed must be extremely rare.