Cosmic dust may have been crucial to the beginnings of life on Earth

Cosmic dust may have provided essential elements for life on early Earth. Our planet is relatively poor in many of the elements that are essential for the chemistry of life, but the dust constantly falling down from space is abundant, and it may have accumulated in ice regions when the Earth was young.

“It kind of lingered as an idea in the shadows, but people rejected it for a number of reasons, the main reason being that it wasn’t enough in any one place,” he says. Craig Walton at Cambridge University Cosmic dust It is rich in elements such as phosphorus and sulfur that are relatively unavailable on Earth, and it continuously falls in a thin layer across the globe.

In the past, researchers looking for the origin of such elements on Earth have largely focused on large objects that can deliver more of them at once, but maintain such a delivery mechanism. can struggle for Prebiotic chemistry Long enough for life to arise, says Walton. “Meteorites have long been considered an excellent source of these elements, but meteorites provide these elements randomly,” he says. “It’s like if I give you a big treat once but never again, you’ll struggle to live a happy life. You need a constant source, and that’s cosmic dust.”

Up to 40,000 tons Cosmic dust falls. every year on earth. Billions of years ago that number would have been 10 to 10,000 times higher, but it still wouldn’t have been enough to make any individual site particularly rich in elements important for life. Walton and his colleagues simulated how dust could be collected by wind and water in large enough quantities to support life.

They felt that the most promising environment was Glaciers, both because they can trap large amounts of dust and because they contain very little contamination from ground litter. When cosmic dust falls on a glacier, it absorbs sunlight and heats up, melting into a tiny hole in the ice. The hole then continues to trap more and more dust. Finally, the dust chamber collapses into a pool at the edge of the glacier.

We can still see this process happening today, but if the Earth had been cold enough for glaciers billions of years ago, the increased amount of dust would have made it more efficient. “If you want to create a sediment that’s really rich and has a lot of reactions that can lead to life, that’s the best way to go,” Walton says.

“It’s not clear whether glaciers were common on the early Earth – we don’t have very good data for that time period in general,” he says. Ben Pierce at Johns Hopkins University in Maryland. “However, I think either possibility is worth studying, especially if it provides a mechanism for making a rich starter soup.”

Lack of data about Conditions on the ground During this period it becomes difficult to say how important cosmic dust could have been to the origin of life. “We’ve always had trouble figuring out what the bulk chemistry of the early Earth was like,” he says Matthew Pasek at the University of South Florida. “But it can be an important source of very valuable material.”