Carl Sagan seems to have been the first person to pursue the idea seriously, and as a result of his projects a total of five messages, including two duplicates, have been sent into space to this end. These are as follows:
1 & 2. The Pioneer Plaques. These were launched with the Pioneer 10 and 11 probes in 1972 and 1973. They include a drawing of a naked adult female and male in front of a diagram of the probe itself to indicate scale, a diagram of the Solar System with a schematic representation of the trajectory taken by the spacecraft, a star-shaped map of the distances to fourteen pulsars in the Milky Way for redundancy purposes, with their periods, and a picture of a hydrogen molecule to indicate the use of the "hydrogen line" of approximately 21 centimetres wavelength, which is used as a base unit for the other measurements on the plaque. All numbers are in binary using a vertical line for a one and a horizontal one for a zero. The Pioneer probes are currently heading in the directions of Taurus and Aquila.
3. The Arecibo Telescope Message. This is a message sent via the radio telescope dish to a globular cluster M13 about 25 000 light years away. It includes the numbers from one to ten, the elements present in DNA, the formulae of the compounds making it up, the population of the planet at the time, the number of bases in DNA, a graphic representing the double helix, a human figure and a picture of the Arecibo dish itself with the size underneath it. The Arecibo telescope has since been used to send a genome sequence for a photosynthesis protein.
4 & 5. The Voyager Golden Record. This is a conventional gramophone record made of metal with recordings in sound and images of greetings in various languages, music and photographs of scenes from this planet. It has an engraving reading "To the makers of music - all worlds, all times" on the playout groove. It was common to scratch messages on the master discs of records at the time, but this almost got the record banned for some reason. There are instructions similar to the Pioneer Plaque on the sleeve of the record. The Voyager probes will both be relatively near two different red dwarves in the vicinity of the Sun in about 40 000 years, not because of their speed but because the stars concerned are both moving towards this solar system quite fast.
Finally, in 2008, a Ukranian radio telescope sent the contents of Bebo for one day to the star system Gliese 581, where it should arrive in about 2029.
Tags: messages, aliens, extraterrestrials, ET, alien, extraterrestrial, carl sagan, voyager golden record, pioneer plaque, CETI, SETI, space, voyager, pioneer, binary, hydrogen line, arecibo, arecibo telescope, bebo, communication, signal, pulsars, pulsar, space travel, galaxy, sagan, gliese, ross, wolf,
This is quite possibly the worst thumbnail i've ever made.
I should probably say something about the pregnancy vlog, and the whole project in fact. I ended up not making one last week and i think the reason is twofold. Firstly, i feel inhibited doing it with other people in the house. Secondly, every week it gets harder to do.
Right: that's it. Tomorrow's video will probably be on one of the regrets of the dying.