Scientists warn public on alien communication

Phone home: Fictional hero E.T. builds an alien communication device from household objects.

If aliens call, what should we say? Scientists are turning to the public to ask how — and if — we should reply to intelligent extraterrestrial life. It could alter the course of history.

For decades, the most powerful telescopes on Earth have listened to the vast cosmos for signs of life. So far, scientists have heard nothing but silence.

But, as our technology improves, the search is accelerating. Now, scientists have stopped to think: if we do receive a message from complex alien life, how should we respond? Should we reply at all?

To find out, the UK Seti Research Network (UKSRN) has launched the largest-ever survey of public attitudes towards alien contact, including questions about who should have the authority to respond, and what the message should contain.

For ideas, we can look to humanity’s past efforts to talk to aliens. In 1974, a group of scientists sent the Arecibo message to a cluster of stars called M13. The radio message contained a graphic of our solar system and a human figure. But don’t expect a reply soon: M13 is 25,000 light years away.

Next year, another organisation, METI International, plans to beam signals with the atomic numbers of different elements in the periodic table. But the UKSRN thinks it could be dangerous for a technologically young civilisation like ours to broadcast our existence across the universe.

Any alien race able to reach Earth, Stephen Hawking argued in 2016, would be drastically more advanced than humanity. And it’s unlikely they would come all this way just to say hello.

“Meeting an advanced civilisation could be like Native Americans encountering Columbus. That didn’t turn out so well,” the physicist warned.

A year before that, a group of scientists — including SpaceX founder Elon Musk — insisted that “a worldwide scientific, political and humanitarian discussion must occur before any message is sent”.

Or is this a waste of time? Are we, in fact, alone? Last month, the Breakthrough Listen project revealed it had found nothing after eavesdropping on more than 1,000 solar systems within 160 light years of Earth.

But, due to the sheer size of our galaxy, astronomers say that even if there were tens of quintillions of intelligent civilisations evenly distributed around the Milky Way, the project would still have heard nothing. We haven’t yet scratched the surface.

Reach for the stars?

How should we respond to an alien message? Perhaps not at all. It could be from a race of nomadic aliens — their home destroyed — scouring the galaxy for a habitable planet to colonise. A civilisation that advanced might see us as a pest infestation.

But we have been beaming high-frequency radio and TV into space for 100 years. If aliens are looking, they can find us. So, why not send a democratic, positive message to the stars from all of humanity? It is an historic opportunity.

You Decide

  1. Are we alone in the universe?
  2. Is it dangerous to try to contact aliens?


  1. Draw a picture of what you think an alien could look like. Give it a name in its own alien language.
  2. Write a message to an intelligent alien civilisation. What would you tell them about humanity and Earth? What do you want to know about them? Write at least three paragraphs.

Some People Say...

“I think the surest sign that there is intelligent life out there in the universe is that none of it has tried to contact us.”

Bill Watterson, US cartoonist and author of Calvin and Hobbes comicstrip

What do you think?

Q & A

What do we know?
The UKSRN has launched a survey to find out how the public think humanity should respond if aliens make contact. Puerto Rico’s Arecibo Observatory sent a message to space in 1974.
What do we not know?
If we would actually believe in contact supposedly made by aliens. Scientists at UKSRN fear that fake news and conspiracy theories would abound if contact with aliens was announced. “It will take time to understand [the message] and if that work starts to drag out and there is nothing new we can say, the information vacuum will be filled with speculation,” said Dr John Elliott, a reader in intelligence engineering. “Conjecture and rumour will take over.”

Word Watch

The most exciting find has been Fast Radio Bursts (FRBs) — repeating bursts of energy from across the galaxy — which scientists thought could come from intelligent alien life. However, we now think it is more likely that they originate from rapidly spinning neutron stars in black holes.
Search for Extra-Terrestrial Intelligence. A collective term for all scientific searches for alien life.
Light years
The distance that light (the fastest thing in the universe) can travel in one year — roughly, six million million miles.
Atomic numbers
Each element is identified with a different number. For example, number one is hydrogen.
Technologically young
We have only had radio technology for 100 years. If the rate of our progress is extrapolated over the next few thousand years, we ought to be able to colonise the solar system, according to some scientists.
Stephen Hawking
Physicist famed for his research into black holes. He suffered from motor neurone disease (MND) and died in 2018.
Milky Way
There are more than 300 billion stars in our galaxy alone.


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