Early life was radically different from today. | Top Vip News

All modern life shares a robust, resilient, and efficient system of intertwined, self-propagating chemicals. This system must have emerged from another simpler, less efficient and more delicate one. But what was that system and why did it appear, precisely on planet Earth?

This is the central question of abiogenesis, the generation of life from non-life. We don’t have an answer to that question yet, but we do have a collection of curious clues and brilliant hypotheses that could point us in the right direction.

First, the chemistry. All proteins on Earth are made up of only 22 amino acids. Those amino acids require abundant amounts of organic molecules, the most basic building blocks of life. Astronomers have detected organic molecules, and even some amino acids, scattered throughout space, from the depths of interstellar gas clouds to the fragile meteorites roaming the solar system.

So it’s natural to assume that our planet, coalescing from the maelstrom that surrounded our rising sun, was born with the right ingredients… but surely they couldn’t survive the initial formation of our planet, when it was still molten by the countless collisions that lead to its development.

Instead, these organic compounds must have reached us long after the planet cooled and solidified. Astronomers believe that the first few million years in the solar system were a rather hostile time. Even after the protoplanetary disk around the Sun evaporated and the system’s eight major planets emerged victorious over their rivals, fragments and debris still littered the orbital routes. Impact after impact hit each of the planets, with new rounds brought about by gravitational rearrangements of the giant outer worlds as they settled into stable, permanent configurations.

Even today we see the scars of that youthful violence, visible on the sterile empty surfaces of the Moon and Mercury.

But in that violence an opportunity for life arose. Fresh water, brought by countless cometary impacts, replaced what the Earth lost during its molten state. And with that water organic compounds rained down on the surface. Here we also see another delicate balancing act. If Earth had been hit very rarely, we may not have been rich enough in molecular resources to begin the ascent to life. However, if too many had arrived, the lingering heat from the impacts would have boiled our oceans and scattered any nascent life into interplanetary space.

We were lucky. Somewhere life took hold. The oldest indisputable fossil evidence of life dates back to 3.5 billion years ago. More speculative evidence: Again, this work becomes extremely difficult the further back we go, because the earliest life was not much different from the non-living chemical reactions that preceded it, so it is difficult to say whether any molecular fingerprints In a The rock is the fossil of a living creature or simply a manifestation of an exotic chemistry, and if there is even a difference between them, it suggests that life began 4.5 billion years ago. That alone is surprising, given the hellish conditions our planet was experiencing at the time, with some scientists arguing that our world wasn’t even habitable until about 500 million years later.

But somewhere, somewhere quiet, magic happened. A casual group of molecules and chemical reactions began to store information, began to self-replicate, and began to catalyze reactions. Some biologists suspect these are deep-sea hydrothermal vents, spewing molecules rich in organic matter into their surroundings. Or perhaps it was in the tide pools, which provided a natural rhythm that would become the cycles of life. Or maybe hot springs, or even underground.

It may have happened more than once and in more than one way, but from all the available evidence it appears that as soon as life could arise, it did.