52: The Thing in the Ice

But before I get ahead of myself, let's step back and review where we are in time and what we've learned about ancient life and ancient Greenland.

Context is key.

In time, we're sitting 3.7 billion years ago, March 11th, on our imaginary Earth calendar, near the end of Season 2.

In Season 1, Earth started off as a bowl of molten rock, a hostile place pelted with asteroids.

By season two, Earth has cooled down and is mostly covered with oceans.

There's lots of water, lots of carbon, and the temperature is just right.

By 3.7 billion years ago, most scientists are sure that life was around.

But proving it is another matter.

Most rocks from this ancient time have been eroded or melted away.

The few rocks that remain are either too warped to preserve fossils or never had fossils to begin with.

The faint glimpses, the possibilities we've seen have been highly debated.

Carbon in Australia, iron in Canada, phosphorus on Arctic islands.

They might be traces of life, but as long as there are alternatives, there's always going to be question marks at best.

Which brings us to southwest Greenland.

These rocks are the most extensive we've seen yet, the area of Rhode Island or Luxembourg.

They're also the most well-preserved we've seen yet, though they're still pretty messed up, baked to at least 500 C or 900 Fahrenheit.

They also preserve the right environments, seafloors rich in water and carbon, the building blocks of life.

So there's a reason we've spent so much time here.

It's an oasis of rocks and data and maybe life.

You might be thanking me as we get into some mysterious eras in the future.

But in the last two episodes, we discussed our best fossil candidates yet.

3.7 billion years old from southwest Greenland.

Even I was surprised.

I was expecting other researchers to pick these little guys apart.

But as of 2025, the latest evidence seems to support the presence of life.