According to a new study published in the preprinted arXiv[1], astronomers developed a binary encoding of information that considered using the Chinese Celestial Eye (FAST) to broadcast the precise position of the Earth and human information to the alien world. Why, then, do astronomers ignore Hawking's warnings and take the initiative to attract the attention of alien civilizations? What if an alien civilization did find humans?
Astronomy progressed, astronomers came to realize that the faint stars in the night sky were mostly huge, hot stars, like the sun. Through astronomical telescopes, astronomers have also observed more stars that are invisible to the naked eye. According to modern astronomy, there are more than 100 billion stars in our milky way alone.
Those stars, like the Sun, are also surrounded by planets, and the number of extrasolar planets that have been discovered so far has reached 5,000, and the number of unknown exoplanets is estimated to be far more than 100 billion. Since there are so many alien worlds, people can't help but wonder, will there be an alien civilization there? Are humans alone in the milky way?
Since the alien civilization has not yet come to Earth, and human beings have not received the signals sent by the alien civilization, astronomers have begun to try to actively inform the universe of the existence of humans and the earth, hoping to get a reply.
In 1972 and 1973, NASA launched Pioneer 10 and 11, two unmanned probes fast enough that they could break free of the gravitational constraints of the solar system and eventually fly out of the solar system. The two probes each carried a gold-plated aluminum plate engraved with basic human information about The Earth's position in the Milky Way.
In 1977, NASA launched Trip 2 and No. 1, which can also fly out of the solar system, and each brought a gilded record, which carried more abundant human information, including various human greetings and sounds, music, and various sounds of nature.
But the two Voyagers and the two Pioneers, which fly at a speed of only a dozen kilometers per second and take tens of thousands of years to fly out of the solar system, are unrealistic to expect them to be discovered by extraterrestrial civilizations in a short period of time. Astronomers then send information out of the sky through radio telescopes with radio waves, which can travel through the universe at the speed of light.
In 1974, astronomers edited the binary message to send information to globular cluster M13 via the Arecibo radio telescope, once the largest radio telescope of a single aperture. M13 is located in the direction of the constellation of Vulcilia and contains hundreds of thousands of stars, where there may be an alien civilization.
48 years later, the original Arecibo information has long left the solar system and has advanced 48 light-years in space. However, M13 is about 22,000 light-years from Earth, and are far from reaching their destination, where the Arecibo message is expected to reach in about 22,000 years.
In the new study, astronomers improved arecibo's information by designing a message called the Milky Way Beacon (BITG). This new information is more detailed and advanced than it was in the past.
The study was first authored by Jonathan Jiang, an astrologer at NASA's Jet Propulsion Laboratory (JPL), and the research was also conducted by the SETI Institute, cambridge university and Beijing Normal University.
In the Milky Way Beacon, astronomers give the time when humans sent this message. In the universe, only one time scale is universal, and that is the origin time of the universe, which is currently believed to have originated from the Big Bang 13.8 billion years ago.
The Milky Way beacon also includes solar system coordinates. In the Milky Way, there is no known unified coordinate system. In order to give the position of the Earth in the Milky Way, it is possible to mark the distance and orientation of the Earth relative to special celestial bodies such as globular clusters and pulsars.
In addition to temporal and spatial information, the Galactic Beacon also contains the double helix structure of human DNA, human physics and technological achievements, etc. The message ends with a digitized image of the human body and invites an alien civilization that received the message to reply to humanity.
Astronomers believe that we can send Milky Way beacons to the universe using the Chinese Sky Eye and SETI's Allen Telescope array. Astronomers figured out the best time to send this year was October 4, because the astronomers chose a concentric ring 13,000 light-years from the center of the Milky Way, when the Earth was facing the silver center at night.
While astronomers greeted alien worlds with kindness, others expressed concern, most notably the late cosmologist Stephen Hawking. During his lifetime, Hawking repeatedly warned humans not to try to get in touch with alien civilizations.
If an alien civilization can receive these signals, it would not be much of a problem to just respond. But if an alien civilization can follow the signal to find Earth and humans, then an alien civilization with a much higher level of technology than humans is likely to pose a huge threat to the existence of human civilization, just as the Indians met Columbus.
While higher alien civilizations may be friendly, or they may not look down on Earth's resources at all, we'd better not take the risk. At least until humanity develops to the point where interstellar flight can be, we should try to remain as quiet as possible in the universe.
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[1] Jonathan H. Jiang, Hanjie Li, Matthew Chong, et al. A Beacon in the Galaxy: Updated Arecibo Message for Potential FAST and SETI Projects, arXiv, 2022, DOI: 10.48550/arXiv.2203.04288.