Messages sent by aliens from space could destroy life as we know it on Earth if we're not careful about how we read them, scientists have warned.
A new paper explores how we might read and understand a message that came to us from space. And it finds that it would be impossible to know that a message was dangerous before we opened it.
In fact, the messages are so dangerous that it would be safest to simply discard them without ever reading them, scientists have warned.
It's unlikely that any alien civilisation we came into contact with would be harmful, researchers Michael Hippke and John G. Learned write in a new study posted on arXiv.org. But since it's impossible to know what the message would say before we read it, the safest scenario would be to avoid doing so entirely.
"After all, it is cheaper for ETI to send a malicious message to eradicate humans compared to sending battleships," the researchers write.
Some have suggested that such a message would have to be "decontaminated" before we actually read it, to ensure that the danger was understood and removed before people came to read it. But the paper – titled "Interstellar communication. IX. Message decontamination is impossible" – suggests that it would be practically impossible to remove that danger.
There are simple ways that a message from space could threaten our world. It could suggest that the aliens are about to destroy our sun, and likely cause chaos even if the message wasn't true, or it could slowly erode things as we know them, as has been suggested the Bible did to the Roman Empire.
But other technologies offer even more technological ways of destroying the world. It could come in the form of a computer virus that infected networks on Earth when it was decrypted, or an artificial intelligence that would then be able to take over our computing systems.
Researchers suggest that it could be possible to build a "prison", that would constrain the message so that it could safely contained. If it came in the form of an AI that learned our language and then answered questions, for instance, it could be run in a secure box on the moon that could only be used by a set number of important people.
But very quickly that AI would find a way to get into the world, they note. It could offer us a cure for cancer, for instance, that relied on nanobots – it's probable that we'd build those nanobots, even if we didn't understand them, and they'd quickly become powerful agents on the Earth even if the computer is securely locked up in space.
In the end, the scientists conclude that we should probably open such a message. The risk is relatively small and the reward is potentially huge, since such a message could give us a way into networks with aliens that could offer us unimagined new knowledge and resources.
As well as helping guide how we should respond to any message received on Earth, the conclusions should help decide what messages we send out, the paper warns.
"We should certainly not transmit any code. Instead, a plain text encyclopedia, images, music etc. in a simple format are adequate," they write. "No advanced computer should be required to decrypt our message."
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