How to talk to aliens (without being killed)

Phone home: Drew Barrymore meets an alien in Steven Spielberg’s ET the Extra-Terrestrial.

A new in-depth article has shed light on the scientists trying to contact aliens. But what if extraterrestrials are unfriendly? Should we really be drawing attention to ourselves?

At this current moment, scientists think there are at least 100 billion planets in the Milky Way, probably more. Of these, tens of billions are in a “habitable zone”.

And that is just one galaxy. The universe contains billions more just like it.

Surely, say astronomers, Earth cannot be alone in supporting life? Intelligent life, capable of science and technology? Capable, perhaps, of contacting other planets?

That is the question that inspired the Search for Extraterrestrial Intelligence institute (SETI), which has been combing the sky for alien signals since the 1990s. Now one of its scientists, Douglas Vakoch, has created a new organisation called METI: messaging extraterrestrial intelligence. He plans to start sending out Earth’s own signals next year.

Yesterday, The New York Times Magazine published an in-depth interview with Vakoch, and many other scientists puzzling over what to say to ET.

For Frank Drake, the question is not hypothetical. He already sent out a radio message in 1974, aimed at a cluster of stars called M13. This depicted the numbers one to ten; the atomic numbers of five key elements for life; the formula for DNA; and three drawings — of the double-helix structure, a person, and the satellite which transmitted the message.

However, even if this is received and understood, it will be a long time before we get a response. M13 is 25,100 light years away from Earth.

Not so for the messages Vakoch plans to send, which will be aimed at newly discovered planets surrounding much closer stars — like Gliese 411, just eight light years away.

Not everyone is happy about the mission. If aliens do understand the message, it is likely that they are more technologically advanced than we are. How can we know that they will not want to hurt us?

“A worldwide scientific, political and humanitarian discussion must occur before any message is sent,” said a group of scientists (including Elon Musk) in 2015.

Hello, worlds!

It is unbelievably reckless to broadcast our existence without knowing who is listening, say METI’s critics — especially without properly discussing it first. We could be inviting our own destruction to our door. Or, as Stephen Hawking put it: “The outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”

That is unlikely, say fans of the idea. Firstly, television and radio programmes have been broadcasting our existence for decades anyway. Secondly, a civilisation advanced enough to intercept the message must have peaceful instincts (because it has not destroyed itself yet). Finally: isn’t it better to be curious and open to the universe, rather than hiding in fear of an attack?

You Decide

  1. Do you want to belong to a species that avoids risk, or one that gambles on saying “Hello”?
  2. If you met an alien tomorrow, what would you say to it?


  1. As a class, design a message to send to potential aliens. Does it involve sound, images, words or all three?
  2. Write a science fiction short story in which Earth receives a radio message from an intelligent species. What would happen next?

Some People Say...

“The Universe is a pretty big place. If it’s just us, seems like an awful waste of space.”

Carl Sagan

What do you think?

Q & A

What do we know?
A handful of other radio messages have been sent since Drake’s first contact attempt in 1974, but so far none have received a response. Physical messages have also been sent on board NASA spacecrafts. Two Pioneer probes had plaques explaining humans and Earth’s location, while two Voyager probes had golden records with sounds and images from Earth.
What do we not know?
Whether alien life really exists, let alone whether it is intelligent. If it did exist, we have no idea what form it would take; the species could have evolved in a completely different way to life on Earth, or invented technology we could not yet comprehend. This is why our messages include maths and physics, in the hope that these are universal concepts that intelligent life will recognise.

Word Watch

100 billion
It is difficult to measure how many stars are in the galaxy, because we cannot see it from the outside. But there are at least 100 billion, so scientists think there are probably at least as many planets. Of these, “tens of billions” are probably habitable.
Radio message
This consisted of 1,679 rhythmic pulses. Why? Because 1,679 is the product of two prime numbers, 73 and 23. If you arranged the pulses into a 73 x 23 grid, Drake’s diagram would be revealed.
On a clear dark night in the Northern Hemisphere, you can just about spot this cluster of 300,000 stars in the Hercules constellation.
Five key elements
Hydrogen, Carbon, Nitrogen, Oxygen and Phosphorous, to be exact.
The twisted structure of two strands of DNA molecules.
Gliese 411
Earlier this year, astronomers said they had detected a large, rocky “super-earth” orbiting this star about 50 trillion miles away. Despite this impossible-sounding distance, it is one of the closest stars to Earth.


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