Because of copyright issues, aliens can't hear the Beatles

In the 1979 movie Star Trek: The Expanse, Voyager 6 was intercepted by aliens, transformed into a self-aware life form and returned to Earth. In reality, in 1977, NASA launched two Voyager probes - Voyager 1 and Voyager 2, which were like two drifting bottles thrown into the universe by humans.

After completing their main exploration missions in the Jupiter and Saturn systems, Voyager 1 and Voyager 2 immediately left the solar system and headed for the depths of the universe. According to NASA's estimates, it will take them 40,000 years to approach any other planetary system.

Voyager 1 | NASA / Wikimedia Commons

Send a postcard to an alien

In 1990, Voyager 1 looked back from 6 billion kilometers away from the Earth and took some photos. The slightly brighter pixels in the vast space of this "Pale Blue Dot" image are its home planet, the Earth.

At 2:00 am on September 13, 2014, Beijing time, NASA announced that Voyager 1 had confirmed to have flown out of the solar system and entered interstellar space. It was not until 2036, when its signal transmission function ran out of power and was forced to cut off the signal with the earth, that it truly began its lonely interstellar drift. The Voyagers had a unique mission on this trip: to take the "Voyager Golden Record" on them outside the solar system. Before that, there had been two "postcards to aliens" activities. Pioneer 10 and 11 each carried a patterned gold-plated aluminum plate designed by cosmologist Carl Sagan - the Pioneer Metal Plate. They set out on their journey to the universe in 1972 and 1973 respectively.

The Pioneer plates feature images of hydrogen atoms, the solar system, the position of the sun, and a naked human figure (an image that has drawn criticism). | Wikipedia

The updated second edition, the Voyager Golden Records, is not just a metal plate, but a record that can be read with more information than the first edition. However, due to official pressure from NASA, all the nude human sketches of the first edition could not be presented on the cover.

The Universe, Love, and Copyright Issues

So what exactly is on this record?

The front of the record contains greetings in 55 languages ​​(including our Cantonese, Wu, Minnan and Modern Standard Chinese), 12 minutes of various sounds from nature and human civilization, and 90 minutes of music from cultures around the world (Mr. Guan Pinghu's Guqin performance "Flowing Water" was selected to represent Chinese music). On the other side of the record, there are 115 images recorded in the form of analog signals and a brain wave.

The audio of this record was released to the public in 1978 under the name "Murmurs of Earth". Interested friends can search and listen to it by themselves.

Voyager Golden Record | NASA / Wikipedia

Carl Sagan's team also went through repeated coordination with many parties. During this period, they even encountered copyright issues, which resulted in the inability to include The Beatles - Here Comes The Sun (can't aliens listen to it for free? How stingy). In order to choose which former Soviet classic music to use, the team also sent a telegram to former Soviet scientists for their opinions.

That brainwave comes from science fiction writer Ann Druyan:

"There was a computer in the lab that converted my brain waves and heartbeats into sounds. For a whole hour, I began to think about the planet we live on and the various lives around us. I tried my best to think about the history of human society. I also thought about the violence and poverty that our entire human race is suffering from, and that there are still so many people on this planet who seem to be living in hell. Finally, I told myself what my love should be like and what kind of person I would marry."

Four years later, she married Carl Sagan, who invited her to record his brain waves.

Alien: This game is so brain-burning

Having said so much, if aliens really received this golden record, how would they decode it?

First, there is a piece of high-purity uranium 238 on the record cover, which allows the aliens to use radioactive dating to archaeologically calculate the time of launch.

Let us take a closer look at the pattern on the golden record.

Illustration of the cover of the Traveler Golden Record, translated by Xiaotong | Wikipedia

Wow, he sent a puzzle game directly to aliens.

When the aliens get the record, they can immediately use the pattern in the lower left corner to locate the position of the earth. This picture shows a pulse diagram, which can lock the position of the earth through triangulation and the distances of multiple neutron stars.

In order to facilitate the actual reading of the information on this record, they gave some other hints on the pattern on the cover of the golden record. The hype-fine transition of hydrogen atoms is depicted in the lower right corner of the record. Through a series of conversions, 0.7 nanoseconds can be obtained. This is the first step in decoding. Then the total length of the record, the required record player speed, etc. can be obtained one by one from the graphics in the upper left corner.

According to Carl Sagan: "There is a record player and needle ready for playback next to the record. Just follow the steps shown on the cover and you can hear the sound from the earth."

However, "playing sound" is only the first hurdle. If aliens can directly read the pattern information on the other side, then it can be confirmed that it is an advanced civilization.

The sound wave pattern in the white square, after being decoded, will appear as a circle in the blue circle | NASA / Wikipedia

The only thing that can be read on this record is sound, and there is no jpg format that the aliens can "see" directly. The so-called "115 pictures engraved on the back of the record" is actually the sound signal converted from the pictures. So when the aliens turn the record over to listen to the other side, further puzzles need to be solved.

It works similarly to an old television tube. When the aliens successfully decoded the pattern in the upper right corner of the record to match the circle below it, it was decoded successfully. The same method was used for the remaining 115 pictures on the record.

Is anyone there? I'm so lonely

Alien: "Why don't you just send me a USB drive instead of going through all that trouble?"

In fact, compared to today's lighter-sized 1TB SSD solid-state drives, the operating system of Voyager 1 more than 40 years ago only had 69KB of storage space. Yes, you read that right. 69KB is now only enough to store a low-resolution jpg image.

In the end, Carl Sagan chose the form of copper LP records, converted all the information into sound signals, and physically engraved them on the records. This not only allowed for enough information to be stored, but the material used could also be preserved longer in the space environment than ordinary vinyl records.

Photo of Jupiter taken by Voyager 1 | NASA / Wikipedia

In this way, two drifting bottles containing the same version of the Golden Record were thrown into the depths of the universe in different directions, carrying the resume of mankind on Earth to the depths of the vast universe, beyond the stars. Assuming that Voyager 1 does not collide with any object until 1 billion years later, even if mankind becomes extinct, the Golden Record will provide evidence of human existence to the aliens who captured it.

As I write this, according to the real-time display of NASA's Eyes, it is 14265.82 million miles away from the Earth, drifting away from the solar system at a speed of 37,928 miles per hour. The ultimate romance of mankind is moving towards the depths of the Milky Way.

Pioneer 10 and 11, Voyager 1 and 2, are traveling in the distant universe | NASA / Wikipedia