David Kipping

And so this is a big problem because one of the ways that we are claiming to look for life in the universe is a chemical disequilibrium.

So you see two molecules that just shouldn't be there.

They normally react with each other.

Or even one molecule that's just too reactive to be hanging around the atmosphere by itself.

So if you had oxygen and methane hanging out together, those would normally react fairly easily.

And so if you detected those two molecules in your pale blue dot spectra, you'd be like, okay, we have evidence for life.

Something's metabolizing on this planet.

However, the challenge here is what if that moon was Titan?

Titan has a methane-rich atmosphere.

And what if the pale blue dot was in fact a plant devoid of life, but it had oxygen because of water undergoing this photolysis reaction, splitting into oxygen and hydrogen separately?

So then you have all of the hallmarks of what we would claim to be life, but all along you were tricked.

It was just a moon that was deceiving you.

And so

We are never going to, I would claim, really understand or complete this quest of looking for life by our signatures in the universe unless we have a deep knowledge of the prevalence and role that moons have.

They may even affect the habitability of the planets themselves.

Of course, our own moon is freakishly large.

By mass ratio, it's the largest moon in the solar system.

It's a 1% mass moon.

If you look at Jupiter's moons, they're like 10 to the power minus four, much smaller.

And so our own moon seems to stabilize the obliquity of our planet.