The Arecibo Message: Humanity’s Greeting to the Cosmos

To this day, one of humanity’s most loaded questions remains unanswered: are we alone in this universe? Though we have yet to detect the presence of any extraterrestrial civilizations, that has not stopped humanity from attempting to make contact with whatever else might be out there.

Globular Cluster Messier 13. Image Source: Wikipedia

The most famous attempt to communicate humanity’s existence to the cosmos was a 3-minute binary transmission made in 1974 from Puerto Rico, a United States territory in the Caribbean. The broadcast was made using a planetary radar transmitter on the Arecibo radio telescope, and it was directed towards a globular cluster called Messier 13 (M13). The cluster contains about a third of a million stars, and the message’s senders hoped that an interstellar civilization ready to accept our transmission might be among these many star systems. However, M13 is near the edge of the Milky Way and lies at a whopping distance of about 25,000 light years. This means that it will take around 25,000 years for our message to actually reach the cluster, never mind the time it might take for us to actually receive a reply.

The Arecibo message encoded. Image Source: SETI Institute

The Arecibo message was the most powerful transmission ever purposefully beamed into space; it was equivalent in strength to a 20 trillion watt broadcast in all directions. The message includes 1679 bits that are meant to be arranged into a rectangular grid of 73 rows and 23 columns. These numbers were chosen because they are both prime, and presumbably, the extraterrestrials would recognize the significance. Once the aliens deciphered the message, they would have discovered the above image (though it carried no color information). Among other things, the picture represents DNA structure, a human stick figure, our solar system, the Arecibo radio dish, and eight biochemicals that define life on Earth.

Though the chances of receiving a reply to the Arecibo message are very slim, the project allowed us to more fully understand the complexities of communicating across time, space, and cultures.

Historical Astronomers in Context: Nicholas Copernicus

Image from Biography

Nicholas Copernicus (February 19, 1473 – May 24, 1543) was a Polish scientist who mathematically calculated the details of a heliocentric, or sun-centered, solar system.  He uncovered relationships that permitted him to calculate each planet’s orbital period and the distance from each planet to the sun in terms of the astronomical unit (AU), or the Earth-Sun distance.  Copernicus also proposed that the Earth rotates on an axis, and this axis changes in direction very gradually to cause the precession of the equinoxes.

While Copernicus was making his discoveries, a lot was happening in the world. From 1508 to 1512, Michelangelo was painting the ceiling of the Sistine Chapel with several colorful and complex scenes from biblical scripture.  On October 31, 1517, Martin Luther posted his “95 Theses” to denounce corrupt practices of the Catholic Church. This document sparked the Protestant Reformation. Italian Leonardo da Vinci (April 15, 1452 – May 2, 1519) was an artist, inventor, engineer, scientist, and architect whose work exemplified the humanist ideal of the Renaissance.

Having previously studied the cosmic calendar, it is already clear to me that on the grand scale of things, human civilization and scientific advancement has only comprised a short blip in the vast history of the universe.  Copernicus was alive during the Renaissance, and it is very fascinating to see how other aspects of civilization were progressing alongside important astronomical discoveries. Around the same time that Copernicus was challenging the geocentric model, Martin Luther was denouncing the established church, and artists like Michelangelo and Leonardo da Vinci were creating masterpieces.  It certainly was a time of great innovation and change.