Mysterious signal hints at nearby alien life
Would aliens look like us? As scientists pick up a mysterious radio signal from the Earth’s closest star, some think we could be on the brink of our first ever alien encounter.
In April 2020, astronomers in Australia picked up a radio signal coming from the direction of Proxima Centauri, the closest star to our solar system. It was artificial. Shifts in frequency suggested it might be coming from another planet.
They believe this could be the most promising breakthrough in the search for aliens since the Wow! signal of 1977. They have named it Breakthrough Listen Candidate 1 (BLC-1).
Next to Proxima Centauri is an exoplanet. Named Proxima b, the planet is thought to be within the habitable zone. This would allow life.
If there are aliens on Proxima b, we could meet them.
Researchers are working on a tiny probe to make the trip. Humans cannot be transported out of our solar system, but an advanced alien civilisation might have the capacity.
If visitors from Proxima b arrive, what will they look like?
Proxima b is different from Earth. Its year are 11 days. It orbits a star that releases radiation. It is probably tidally locked with its sun: half of it in constant day, and the other half in constant night.
Its only habitable space a thin band in eternal twilight.
These visitors would likely have huge eyes and less tolerance for temperature changes.
The pressure on Earth could crush their bodies. They would be physically stronger than humans.
They would have two limbs and digits.
Would aliens look like us?
Peas in a pod
Yes. To develop technology, the aliens would have problem-solving capacity and dextrous limbs. They must have language. They probably share that fundamental human trait: curiosity.
No. Alien life would have evolved differently. Their civilisations might have developed differently, they might have different moral questions. Their way of thinking could be completely incomprehensible to us. They might not be able to survive on Earth.
- If you were in charge of showing an alien tourist around Earth, what would you take them to see?
- What would an alien visiting Earth from Proxima b for the first time think of our home? Write a diary entry from its perspective.
Some People Say...
“We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.”Stephen Hawking (1942 - 2018), British physicist
What do you think?
Q & A
- What do we know?
- Most people agree that it was vanishingly unlikely that an extremely intelligent species like humanity would evolve at all. In 3.5 billion years of evolution on Earth, no other species has developed that is capable of such advanced problem-solving, and of shaping its environment to suit its needs. Indeed, it is only in the last 10,000 years that humanity has really explored the potential of its intelligence. If we go extinct, it is unlikely that anything like us will ever appear on Earth again.
- What do we not know?
- There is some debate over what the effect of disease would be on alien visitors. For millennia, humanity was separated into two halves: one in Eurasia, one in the Americas. When they met each other again in 1492, Eurasian pathogens decimated the population of the Americas. If human pathogens were able to infect aliens, or vice versa, the same could happen. In HG Wells’s book The War of the Worlds, invaders from Mars are defeated not by human weapons, but by disease.
- Radio signal
- Stars and many other astronomical objects emit radio signals, meaning that studying radio waves is a good way of investigating the cosmos. Because they travel well in space, it is possible that aliens might communicate with us using targeted radio signals.
- Wow! signal of 1977
- In 1977, the Big Ear radio telescope in Ohio picked up a strong radio signal, lasting 72 seconds, which bore all the hallmarks of extraterrestrial origin. When it was spotted by astronomer Jerry R Ehman, he simply wrote “Wow!” next to it, inspiring its name. It has never been detected since.
- Any planet outside the solar system. So far we have confirmed the existence of 4,395 exoplanets, but there are likely to be at least 100 billion in the Milky Way alone.
- Habitable zone
- The area around a star that is neither too warm nor too cold for liquid water, believed to be essential for complex life to exist. As many as 40 billion might exist in the Milky Way.
- Tidally locked
- When the same face of a celestial body is always turned towards the object it orbits. The moon is tidally locked with the Earth. On a planet, it means that one side is always extremely hot and the other extremely cold.
- Dexterity means having fine motor skill, the ability to carry out intricate tasks. It comes from the Latin “dexter”, meaning “right”, since in most (but not all) human beings the right hand is more dextrous than the left.