Look, the first message sent by humans to the universe is the real broadcast era

Arecibo's first active signal sent into space

(Illustration: On November 16, 1974, the Arecibo Observatory sent its first active signal to the universe. Image source: Wikipedia Commons.)

The first unintentional signal sent into space in 1974

On November 16, 1974, astronomers used the Arecibo telescope in Puerto Rico to conduct an unprecedented, maximum-powered active broadcast to the universe. Astronomers said that this was to get in touch with extraterrestrial life. There are many different opinions about this purpose. Those who support it believe that this will tell people that the earth is not the only planet in the Milky Way with intelligent life; at the same time, some people oppose it, saying that if there are really aliens in outer space, it would not be a good thing to attract their attention.

The information contained in this signal

Scientists have given this information a lot of thought, including Frank Drake, an astronomy professor at Cornell University, and Carl Sagan.

Finally, it condensed into a concise broadcast content. In general, it consists of a set of binary numbers. Among them are information about the basic elements of life and the structure of DNA. Not only that, it also includes the position of the earth in the solar system, and even a stick figure representing the image of a human being.

(Illustration: The Arecibo telescope in Puerto Rico used to transmit this message. Image source: Wikipedia Commons.)

How did Arecibo send this message?

It took Arecibo three minutes to send the 1,697-byte message, which is a snail's pace compared to today's computers! The SETI Institute said:

The broadcast is powerful because it uses Arecibo's megawatt-class transmitter and an accompanying 1,000-foot (305-meter) antenna, which is used to focus the transmitted energy and send the signal to a very small patch of sky. The transmission is equivalent to a 20-trillion-watt omnidirectional broadcast, and it can be observed by SETI anywhere, as long as the receiving antenna is the same as the transmitting antenna.

In fact, the 1974 signal was sent in the direction of the M13 cluster, a globular cluster orbiting the center of the Milky Way. Simply put, it was chosen because it contains a large number of stars that could be observed at the time and place of the transmission.

(Illustration: M13 Hercules globular cluster. Source: NASA)

Now, the signal is almost 50 light-years away from us.

What do you think? Should we announce our existence to the universe?

Related knowledge

The Milky Way is a galaxy that contains our solar system. Its name comes from how it looks from Earth - a hazy band of light in the night sky, made up of thousands of stars that cannot be distinguished by the naked eye. The English name for the Milky Way is Milky Way, which is a translation of the Latin "lactea" (milk), which comes from the Greek γαλακτικός κύκλος, meaning milky circle. From Earth, the Milky Way looks like a long band because we see its "silver disk" structure. In 1610, Galileo Galilei became the first person to use a telescope to distinguish individual stars from the band of light.

Until the early 1920s, most astronomers believed that the Milky Way contained all the stars in the universe. It was only after the 1920 Great Debate between Harlow Shapley and Heber Curtis that Edwin Hubble showed through his observations that the Milky Way was just one of many galaxies in the vast universe.

(Illustration: See the text in the picture. The picture on the right is labeled: disk-accretion disk, Sun's location-the location of the sun, bulge-the core ball of the Milky Way, halo-nuclear halo, light-years-light years. Image source: SlideServe)

BY: Deborah Byrdand

FY:Stella (Zhang Shuling)

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