Alex McColgan

Did life on Earth start on Mars, or the other way round?

Did a meteor from interstellar space seed life on both our planets?

Or did it arise spontaneously twice?

Where else could life exist in the universe?

How common is it really?

It would also have implications on the Drake equation, a probabilistic formula used to estimate the number of alien civilizations in our galaxy.

The FL value here,

which stands for the fraction of potentially habitable planets that go on to develop life, would jump from vanishingly small to closer to one.

Since two out of two neighbouring planets would then have or have had life at some point, an increase in this value causes the number of civilisations in the universe to shoot up.

But crucially, this coefficient only changes if life on Earth and Mars rose independently.

If we are related, the products of panspermia, that still represents just one biogenesis event, and the outcome of the equation remains unchanged.

There's a concept known as the zero-one infinity rule.

In astrobiology, it represents the idea that life can only exist in zero, one, or infinite places.

We already know it's not zero.

If it's just one, then we're alone, a single spark in the dark.

But if it's two, Earth and Mars, then why not five?

Five thousand, five million, or even infinite places in the universe.

Suddenly, life isn't rare.

We're not special anymore.

And personally, I hope that if we ever discover life out there, it brings us closer together down here.