"Attention human.
You are receiving an interstellar
radio transmission."
And it could be coming from
one of the nearest exoplanets,
Proxima Centauri b.
At a distance of 4.2 light-years away,
Proxima Centauri is one of the
closest stars to our Sun.
In 2016, a planet was discovered
orbiting in Proxima Centauri’s Goldilocks zone.
That’s where conditions for
liquid water could exist.
Meet Proxima b.
A planet that registers at 0.87
on the Earth Similarity Index.
This scale measures how similar a planet or moon is to Earth,
and anything above 0.8 is considered Earth-like.
As another example, Mars has an ESI of 0.64.
In 2020, astronomers recorded a mysterious radio signal
coming from the direction of Proxima Centauri.
Could it be that an alien civilization
was attempting to contact us?
Though Proxima b is similar to Earth,
lifeforms on this alien planet
would likely develop very differently.
For starters, the planet is about 20 times closer to its star
than Earth is to the Sun.
And it only needs 11.2 days for one full revolution.
That’s a lot of New Year's celebrations.
But still, Proxima b receives about the same amount
of solar energy as Earth.
That’s because Proxima Centauri is an M-type red dwarf star.
Compared to our G-type Star,
these stars are generally cooler
in a range of 2,200-3,200 °C (4,000-5,800 °F).
But there would be some extreme conditions
that an alien civilization would have to adapt to.
These extraterrestrials
would need to be able to withstand radiation.
And lots of it.
The planet receives about 400 times more X-rays than Earth.
And dwarf stars like Proxima Centauri
give rise to coronal mass ejections
that would blast the planet with lethal radiation.
Without a protective atmosphere,
this would be deadly for any potential lifeforms.
Another challenge for a Proxima b civilization would be tidal locking.
That’s when a planet takes the same amount of time
to spin on its axis as it does to orbit its star.
Imagine living where you
permanently face the scorching Sun
while the other side of the Earth
is in a constant state of frozen darkness.
This is what life would be like on this exoplanet.
Civilizations on Proxima b
would likely develop in the so-called terminator zones.
These are the strips of twilight
between the dayside and the nightside.
Here, winds would carry warm air
and create life-supporting conditions.
And aliens would build thermal reactors
with the mix of cool and hot water
to have that H2O always available.
But if civilizations appeared
on either of the sides of the terminator zone,
they'd need to develop different survival tactics.
But collaboration and unity
could allow them to supply each other with heat or ice effectively.
And if a civilization developed on the light side,
would they even know
that there were other stars or objects in the Universe?
Would they even think about other life out in space?
That brings us back to the radio signal
the Breakthrough Listen project recorded in 2020.
This signal occupied a very narrow band
of the radio spectrum at 982 MHz.
This is startling because
it’s a portion of the spectrum
rarely used by human-made transmitters.
Researchers haven’t ruled out the possibility
that these signals originated on Earth,
but there are many unanswered questions.
One thing they're sure of,
it didn't come from a natural world.
Only manufactured,
or alien-made technology,
seems to produce signals like that.
So if an advanced civilization
was trying to communicate with us from Proxima b,
what would their society be like?
They could be a Type I civilization like us
and use the energy available from their planet,
like oil, wind or geothermal power.
Or they could be a Type II civilization,
using energy on the scale of their planetary system.
That would mean they were
thousands of years more advanced than us.
Would they have developed complex languages and live in cities?
Would they have democratic forms of governance?
Or would they live under the rule of a dictator?
You must have so many questions for our alien neighbors.
And they would have so many questions for you.
Or maybe they already know everything.
Unfortunately,
we likely won't be able to visit them any time soon.
Using current technologies,
it would still take between 19,000
and 81,000 years to reach them.
Of course,
maybe they could travel faster than the speed of light,
and get here first.
And who knows what would happen
when they finally get here.
For all we know,
they could take over our planet and enslave us.
But that's a story
for another WHAT IF.