Week 11: The Arecibo Message

On Thursday, our lecture covered astrobiology. While a lot of this field focuses on life as a more general phenomenon, the exciting part of astrobiology for most people is almost definitely the idea of finding intelligent life off of the Earth. However, since the only example of intelligent life that we have is ourselves (and even that can be questionable sometimes), we don't know anything about the culture, capabilities, or even biology of potential life elsewhere in our universe, and it can be difficult to be confident in our definition of intelligent life.

Given our lack of knowledge regarding what we might share with other civilizations, scientists wanted to come up with the most simple and universal way of demonstrating humanity's intelligence. Thus, in 1974, the Arecibo message was born. This message contained what Dr. Frank Drake (of the Drake equation, which we discussed in lecture) and Dr. Carl Sagan deemed the most important information about and known by humans, including the numbers 1-10, the chemical formulas of the nucleotides, Earth's location within our solar system, and the population of Earth. Once the information was assembled, the message was transmitted via an extremely powerful radio broadcast in the direction of a star cluster called M13.

A graphic representation of the Arecibo Message. Its dimensions were chosen as 73x23, because prime numbers would lead to minimum confusion when reconstructing the information. 

M13 was chosen because it has a large number of stars, is relatively big, and is relatively close. However, "close" in this case means about 25,000 light years away--which means that it won't be another 24,958 years or so before the Arecibo message reaches M13, and another 25,000 years or so after that before we could possibly get a response. While very little of the information encoded in the message has changed since 1974 (only the Earth's population and the fact that we have demoted Pluto from planethood), a lot can change in 50,000 years--the disappearance of the Neanderthal and all of recorded history are just two small examples of things that have happened in the last 50,000 years, for instance. It's unlikely that the Arecibo Radio Telescope, from which the signal was broadcast and which is represented in the message, will still be around in 50 millennia.

Our understanding of the universe will have changed a lot by then too. Just given how much physics has advanced since 1974 and the accelerating trajectory that that advance has taken, it's possible that at some point before 50,000 years have elapsed, we'll look back on this transmission with embarrassment. "Why did we think it was important to show that we knew how to count to 10? Any respectable civilization would have understood and included the unified field theory instead," we will lament, with the same emotions one feels upon looking at pictures of him- or herself from middle school.

In any case, the Arecibo message is less of an exercise in practical extraterrestrial communication than it is in thinking about what's important and how we can communicate with cultures unimaginably different from ours. That being said, if we haven't made contact with aliens by 51,974, it'll be a suspenseful year for anyone who remembers this transmission.




Sources 
https://en.wikipedia.org/wiki/Arecibo_message
http://phenomena.nationalgeographic.com/files/2014/11/AreciboMessage-e1417162442960.jpg
http://www.seti.org/seti-institute/project/details/arecibo-message
https://en.wikipedia.org/wiki/Messier_13
https://en.wikipedia.org/wiki/Neanderthal
http://outline-of-history.mindvessel.net/80-the-neanderthal-man-an-extinct-race/81-the-world-50000-years-ago.html