About 4.4 billion years ago, a Mars-sized planet crashed into Earth. This cataclysmic event actually made Earth melt, and the fallout from the collision became the Moon. So how did Earth's earliest organic molecules hang on during these apocalyptic times?

Although this collision happened long before life emerged on our planet, the basic building blocks were already in evidence in the form of organic molecules. Simulations of the collision suggest that Earth really did melt for a brief time, meaning that all lightweight materials like carbon and water would have been utterly vaporized. So, under those extreme circumstances, what allowed the organic, carbon-based molecules to hang on and, ultimately, develop into life?

Formaldehyde, of all things, might be the answer. This extremely poisonous carbon compound happens to be very reactive, allowing it to lock in hugely complex - but stable - chains of other molecules. The formaldehyde could have incorporated the more lightweight organic molecules before the planetary collision, giving life's building blocks the extra weight needed to survive.

Indeed, recent experiments show that formaldehyde-based polymers can survive in temperatures well over 2,500 degrees Fahrenheit, more than enough to stave off the extreme temperatures kicked up all those billions of years ago. We know that formaldehyde is common in cosmic molecular clouds, so there's good reason to think Earth had plenty of this vital compound. Best of all, recent evidence of organic molecules on comets suggest that they are capable of huge complexity, and laboratory attempts to replicate these comet molecular configurations using formaldehyde have been very encouraging.

So then, it appears that all life on Earth owes formaldehyde a debt of gratitude, as without this now incredibly deadly poison we probably wouldn't be around today. Who says the cosmos doesn't have a sense of irony?

Via Discovery News.