Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: SF Chinese (ID:kexuejiaodian), author: SF

On September 12, at the scene of a hearing in the Mexican Congress, two mysterious ancient corpses with a history of thousands of years were displayed. Unexpectedly, Mexican officials announced the discovery of aliens, and Mexico became the first country in the world to recognize the existence of aliens. Although many people do not agree that this is a real alien, our yearning and imagination for aliens have never been lost by repeated failures and blows. However, if we change our way of thinking, maybe the aliens are also struggling to find us!

/ tr. by Colin Stewart (Colin Stuart)

Translation | Li Tiantian

Editor | Zhao Jiaming

The original article is published in Science focus, No. 10, 2023.

Imagine if you are an alien living on a distant planet, like us, eager to let others know about your existence. So, what measures should you take to let others find you? New research shows that alien civilizations may use current supernova explosions to send signals.

Why would alien civilizations choose supernova explosions to send signals? Supernova explosion is the most dazzling astronomical event in the universe that we know so far. When a star comes to the end of its life, it explodes. At that time, it will emit the equivalent of 10 billion suns, releasing as much energy as the sun has released in the past 10 billion years.

As a result, every supernova explosion attracts the close attention of many astronomers, and it is so dazzling in the dark universe.

In May 2023, Japanese astronomer Koichi Sakamoto discovered SN 2023ixf. The arrow in the picture refers to this supernova. (photo source: NASA)

In May, astronomers discovered that SN 2023ixf, a supernova in the pinwheel galaxy, also known as M101, exploded. James Davenport (James Davenport), an assistant professor at the University of Washington, said: "SN 2023ixf is the closest supernova that humans have discovered to Earth in the past 10 years." Although M101 is 2100 million light-years away, the brightness of the supernova explosion can be seen even by astronomers using unprofessional telescopes.

As a result, Davenport's team came up with a hypothesis to explain why alien civilizations send messages through supernova explosions. Because supernova explosions are so dazzling in space, alien civilizations will combine signals with the light emitted by supernovae to send us specific messages. Scientists call this strategy "signal companionship". "if aliens do this, it's like they're shouting'We're here'in a very conspicuous way," Davenport said. "

In addition, since alien civilizations can consciously want others to find them, they will also realize that civilizations from other planets, such as Earth, are probably looking in the direction of a supernova. This will also greatly increase their chances of being discovered.

How to search for signals sent by alien civilizations through supernova explosions? Before we answer this question, we need to figure out where to search for these signals in the vast universe. For specific supernovae, scientists have designated an oval region in the Milky way as the search area, the "SETI ellipsoid" (SETI is the acronym for the search for Extraterrestrial Civilization Project). Aliens must be closer to the supernova than we are so that they can first see the light emitted by the supernova and have time to be ready to transmit the signal.

Through supernova explosions, stars can scatter most or even all of their matter outward at a speed of nearly 1/10 light, and radiate shock waves to the surrounding interstellar matter, forming a shell-like structure of expanding gas and dust. This is how the Crab Nebula formed. (photo source: NASA)

Right now, scientists are most interested in extraterrestrial civilizations at the edge of the SETI ellipsoid. Because we have missed the accompanying signals from the planets inside the ellipsoid, and alien civilizations on the edge of the ellipsoid may have seen supernovae, but their accompanying signals have not yet reached Earth.

The theory is perfect, but the reality is bleak? So the question comes again: the "SETI ellipsoid" is defined for specific supernovae. Which supernovae should we delineate these observation areas? Which planets in the region do we need to pay attention to? In fact, it was not until recently that scientists were able to determine which planets were in the right place to send accompanying signals. The Gaia probe provides us with precise location information for many planets. So far, scientists have found that about 100 of them are in the right position.

However, the scientists' observations have not yielded much because they do not know how long it will take for the accompanying signal to reach Earth after a supernova explosion.

Davenport guessed: "Alien civilizations may have to apply to the relevant agencies of their planet for permission to send." As a result, the accompanying signal may be delayed to reach Earth by several weeks. Based on this uncertainty, astronomers choose to observe these exploding supernovae over and over again, rather than just observing for a few minutes and claiming nothing.

What are the chances of finding alien civilization signals? Over time, the light and accompanying signals from supernova explosions will spread to farther areas in space, and alien civilizations on planets farther away from supernovae may observe supernova explosions to send their accompanying signals. As a result, the "SETI ellipsoid" set by scientists is constantly changing. The planet located at the edge of the ellipsoid has naturally become the most interesting target for scientists. In the next few years, scientists may be able to observe suitable planets at the edge of the ellipsoid.

It could take thousands of years for us to detect signals from alien civilizations, Davenport said. But that's not a problem-a thousand years sounds long, but humans have been doing a lot of things for thousands of years. For example, the University of Bologna, the oldest university in Europe, has been nurturing students for thousands of years since 1088.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.