Perhaps the greatest mystery of modern science is how did life emerge on Earth? There are theories now that suggest life itself is foreign in origin, coming from somewhere else in our galaxy. At first, this seems crazy, and impossible. How can primitive life forms travel vast distances of empty space?
However, as one tries to disprove the idea, it begins to become obvious how possible it actually is. This theory known as Panspermia has begun to gain some momentum in recent years. Recent discoveries in biology and astronomy have been able to turn this once unthinkable idea into something that is more plausible.
Mystery of Life on Earth
Over the past couple centuries, we have been able to prove that life had evolved from simple single cell organisms into the complex biodiversity we see everywhere today. However, no one knows what the first organism was or how it came to be.
In labs and out in the field, scientists have not been able to create or find the original organisms which all life stems from. They have replicated the early conditions of Earth, simulating the different atmosphere, temperature, frequent lightning strikes, and several other conditions. But they have never been able to get life to emerge from these experiments.
There is a possibility that scientists are just missing part of the equation of life. There could be some unknown factor that morphs the necessary groups of molecules into something that resembles a living organism. However, there is another possibility. It is possible that life formed in an environment not familiar to Earth. Life may have needed some alien conditions to emerge.
Life Surviving Space Conditions
The most obvious objection to this theory is that it is impossible for life to survive in the emptiness of space. For most life, yes this is absolutely true. Humans and other animals would not last long in the vacuum of outer space. The low pressure would cause our blood to boil; like a diver with the bends, the lack of oxygen would cause us to suffocate; the cold temperatures would cause almost immediate frostbite; and the radiation absorbed from the Sun would damage our DNA.
Most single cell life forms would face a similar demise in this empty void. However, there are some who are, amazingly, able to survive in this climate; the hardy tardigrade, as well as some other types microbes and bacteria.
Some Microbes and Bacteria Can Survive in Space
Tardigrades are capable of curling up into a ball, and surviving radiation, low pressures, and low temperatures. In fact, astronauts placed tardigrades on the outside of the space station as part of an experiment. They checked some time later to see if they had survived, and they had.
There have also been other microbes and bacteria known to be able to survive in space. Some have even been found surviving 25 miles into the upper reaches of our atmosphere.
Okay, so it is possible for some organisms to survive being in empty space. This still does not explain how they got here in the first place. It is extremely unlikely that an alien ship transported creatures here, a process otherwise known as directed panspermia. Well, after looking into the turbulent history of our own planet, it starts to become pretty clear how life may have traveled vast distances in empty space.
Lithopanspermia: Transfer of Organisms in Rocks Between Planets
The Earth was subject to many heavy bombardments in its early history. These are periods in the early solar system where planets were still forming and there was still a lot of debris orbiting our young Sun. As the Earth began to form, its stronger gravity pulled in more and more of this debris. Sometimes, the Earth was hit by enormous asteroids, sometimes as big as planets themselves. When these enormous collisions happened, massive amounts of debris from the Earth’s surface was blasted into space.
Some of it orbited the Earth and eventually came crashing down again. But a lot of it exited the gravitational pull of our planet and flew out into space. It is possible that primitive life existing within the rocks of the Earth during one of these collisions could have survived. If so, it would have been shielded from the harmful rays of radiation by the matter surrounding it, and could have been possibly transported with its food supply.
Evidence For Panspermia
Astronomers have already sent probes to comets within our solar system and that were able to discover numerous amino acids. Amino acids are the building blocks of protein, a very necessary food source for most forms of life. Who knows how long these organisms would be in space for but if they were lucky, eventually the gravitational pull from another body would pull it towards its surface. If this asteroid hit at the correct angle, and landed in water, it is possible for whatever organism that was on board to have survived.
In our solar system, we have been able to confirm that rocks have been transported from one planet to another. We have found debris from Mars and other planets on Earth. It could be possible that Mars, or even Venus were the birth places of life and then it was simply transported here during the turbulent beginnings of our world. It’s even hypothesized that life could have come to Earth from outside the solar system itself. Transported on the debris from planets destroyed in supernovae millions of years ago.
Did Extraterrestrial Life Reach Earth?
The Panspermia theory is a difficult theory to prove. However, it gives a possible explanation to one of the most powerful questions man has asked. The evidence around us shows the possibilities are there. Some may find it unlikely to be possible, but all things considered, the formation of life itself seems unlikely when one thinks about it.
Even with our modern technology, millions of hours of thought, supercomputers running endless hours of computations, we have still come no closer to solving the ancient riddle of how life began. Life probably shouldn’t exist, but here it is! In all likelihood, we will never find the source of life. Even if the Panspermia theory is confirmed, it still will not get us any closer to figuring out how life actually formed. It would just reveal that we are in fact descendants of extraterrestrials.
There is, however, one perspective on this theory that should give any reader comfort. It shows that we are connected with the Universe that surrounds us. All the planets and stars that are out there that seem hopelessly far away, are connected to us. We may not be an isolated species, alone in the cosmos, orbiting a speck of dust in a vast sea of emptiness. We may just be a small part of an immense bio verse that could never have been imagined even just a few decades ago.