News in space - Part 1
Almost 100 years ago, mankind began to proclaim its existence in space.
With the invention of the radio over 100 years ago, people began to communicate via radio signals. However, these radio waves did not remain exclusively on Earth, but still penetrate the depths of space at around the speed of light to this day. As a result, the signals now form a sphere around the earth with a diameter of 200 light years. They have thus already reached around 1,000 stars and their potential planets, and a study from 2021 even shows that 75 star systems have received these radio signals and could easily find our Earth using the so-called transit method. (1)
This unintended signal sphere is filled with the most diverse radio waves that we humans have sent since then. Some of them, however, are very much intentional and were created for research purposes.
In the 1960s, the modern SETI - Search of ExtraTerrestial Intelligence - project was launched, in the course of which the search for traces of living beings outside the Earth was actively pursued and is still being pursued today.
"Only by doing the best we can with the very best that an era offers, do we find the way to do better in the future."
Frank Drake, SETI-Initiator, Astrophysiker, 1979
The Arecibo Embassy was also created in the process. It is named after the former Arecibo radio telescope in Puerto Rico, which is also known from various films, including James Bond's "Goldeneye" and "Contact".
The message (see image below) was sent on November 16, 1974. It contains (in the graphic from right to left) the basics of our mathematics, various information about our DNA and its structure, the average size of a human being, the size of the human population at the time (4 billion), a schematic representation of the solar system with Earth marked as the third planet and an image of the Arecibo telescope. (2)
The destination of the message is Messier 13, a globular cluster in the direction of the constellation Hercules, as there is a high density of stars there and therefore potentially many recipients. (3) However, the Hercules star cluster is 25,000 light years away from us, so humanity will have to wait around 50,000 years for a possible response from living beings in it.
In addition to radiation signals such as the Arecibo message, physical messages were also sent out into space on space probes.
More on this in part 2 of the series "Messages in space".
Sources
(1) L. Kaltenegger & J.K. Faherty, (2021): Past, present and future stars that can see Earth as a transiting exoplanet | Nature
(2) Arecibo Message by Frank Drake et al, Arecibo Observatory (Cornell University)
(3) M13 Hercules Globular Cluster by ZTF, Giuseppe Donatiello
Author
Dorothea Holzschuh
Teamleader Planetarium