This means that the first living cell, the Last Universal Common Ancestor (LUCA) of all living things, arose very quickly - in a space of about 200 million years. The article goes on to explain why a brief window for the origin of life is significant and the strange theory being resurrected to explain it:
While the exact dating of LUCA might seem unimportant to many readers — what’s a few hundred million years in the grand scheme of things? — the timing has far-reaching implications. If Moody and colleagues are correct, it means life arose extremely rapidly, almost as soon as our planet became habitable.There are two important admissions in the above excerpt. Not only does recent research indicate that life arose amazingly fast, scientists don't have any idea how it could have done so. The level of complexity of the first cell, the LUCA, is so high that to think it came about through random chance and the laws of chemistry alone requires an enormous faith in the power of serendipity.
According to our present knowledge, Earth formed about 4.56 billion years ago, and the Moon formed (violently) about 100 million years later. That leaves a very short interval, maybe just 200 million years or so, before the first living cells appeared. Moody’s team also found that this early life was already quite complex, encoding about 2,600 proteins, comparable to modern bacteria. It even had a primitive immune system that defended it from viruses.
Can the appearance of life really be that rapid, something like the inflationary phase of the Universe right after the Big Bang? That’s certainly faster than most of us previously thought. And if it happened that fast, shouldn’t it be relatively easy to decipher the steps life took to develop?
Yet we still have no real handle on how all the functional components came together. We don’t even know for sure in which type of environment life originated. Maybe it was near “black smoker” hydrothermal vents, but it could also have been in ponds, tidal flats, or other locations. We just don’t know.
Philosopher of science Stephen Meyer writes about the difficulties involved in any naturalistic theory of the formation of the first life in two excellent books, The Return of the God Hypothesis and his earlier, perhaps more technical work, Signature in the Cell.
To put it in layman's terms, the chances of those 2600 proteins forming along with the instructional material encoded in nucleic acids, along with a membrane to encase them all, along with the ability to replicate itself is somewhat like imagining that all the minerals necessary to build a computer were scattered across the surface of the earth and that the action of natural forces like sun, wind, lightning, etc. acting over a span of 200 million years, somehow produced a fully functional computer along with the operating software necessary for it to work properly and also with the capacity to replicate itself.
The inconceivable improbability of such a feat places a severe strain on the credulity of many scientists so some of them, in order to avoid the conclusion that a transcendent intelligence designed the LUCA, are resorting to a theory called panspermia:
The breathtaking speed with which life appeared on Earth opens the door to another intriguing possibility known as “panspermia” — the idea that life originated on some other planet and arrived here inside meteorites. It’s an old idea, usually dismissed because it appears statistically very unlikely.Even naturalistic scientists keep drifting back to the idea that life on earth required an intelligent agent to at least get it started. Here's Schulze-Makuch:
I agree with that evaluation if the incoming meteorite came from outside our Solar System: Traveling through interstellar space for eons would likely sterilize any life forms due to harsh radiation. What’s more, any object arriving from so far away would be much more likely to fall into the Sun or Jupiter due to their much stronger gravitational pull.
But it’s a different story if a life-seeding meteorite came from Mars. It’s entirely plausible that life arose on the Red Planet independently. Our two worlds formed at about the same time, but Mars cooled much faster than Earth, and the geological record suggests that, shortly after its formation, the planet was habitable with plenty of water.
Without a large moon to violently interrupt its early years, the life-starting window on Mars was actually longer than it was on Earth. And because Mars has lower gravity, rocks blown off its surface by asteroid impacts escape the planet more easily, to be hurled into the inner Solar System — toward Earth. The hundreds of Martian meteorites already discovered on Earth are proof of that.
As long as we’re speculating, we might also consider another theory known as “directed panspermia.” More than 50 years ago, Nobel laureate Francis Crick (co-discoverer of DNA) and Leslie Orgel suggested that a highly advanced extraterrestrial civilization could have seeded Earth on purpose, exposing our planet to the first primitive cellular life, which, after gaining a foothold, would evolve to become more complex and even intelligent.He acknowledges that the panspermia hypothesis has some serious problems, however:
As intriguing as the panspermia hypothesis may be, indications still point to life getting its start right here on Earth, considering, for example, the similarity of Earth’s primitive oceans to the interior of microbial cells in terms of elemental abundances (cells are essentially bags filled with salt water!). In any case, if life did indeed begin somewhere else and arrive rather than arise on Earth, we still don’t know how it happened.Here's a question I have about all this: Suppose panspermia is ultimately found to be scientifically untenable. Where does that leave a scientist whose entire worldview is predicated on a naturalistic explanation of the origin of life?
