Was the point of origin of life on Earth somewhere in the cold reaches of space? While the theory was largely laughed at in the past, acceptance of the idea that the origin of life on Earth was from space, and outside of our planet or even galaxy has grown recently. This comes with the realization that places even within our own solar system where conditions are not ideal may indeed harbor life, as well as the startling realization that life can exist in the vacuum and radiation outside of our atmosphere. Each of these has been explored and given more scientific scrutiny in the past few months, most recently in December.
The theory that the origin of life on Earth came from space is known as panspermia. At first blush, panspermia as the means by which life arrived on our planet from space is a long shot. This would have had to happen either by life hitching a ride on a comet or meteorite that strikes the Earth or by cells or spores drifting down from the vacuum of space into the atmosphere and settling to the ground to further develop. Life arriving by meteorite or comet would have to survive the intense high temperatures and physical shock of atmospheric entry. The life resulting from these basic cells eventually evolved into the variety of organisms that exist today.
It seems crazy, so why give it serious consideration? The high school version of how life originated is that life came to be in a random chemical soup somewhere on Earth billions of years ago. The ingredients in the soup were formed by a variety of possible processes, such as exposure of organic molecules in the atmosphere at the time to the heat or radiation from the sun, lightening or underwater volcanic vents that caused the ingredients to change into the molecules of life. Somewhere over time, just the right combination of these molecules were in the right place at the right time for a primitive, single-celled living organism to be formed.
Given our present technical abilities and understanding of the mechanics of how the parts of each cell functions, this sounds as though it should be a process that could be easily replicated. Surely, skilled and knowledgeable scientists in a sophisticated, high tech laboratory should have been able to accomplish the same feat. In spite of many tries in the laboratory, however, no one has succeeded in creating a living organism from scratch. There have been some half-successes in which a part of a living cell has been transplanted into an artificial cell that functions afterward, but these have always transported some “spark” or other characteristic of life to the new “cell.” There is some aspect, some element of the condition of a lump of organic material that turns chemistry into biology.
If groups of researchers who create ideal conditions for imparting the “spark” of life with all the right ingredients can’t jump start an organism, then what does it require? What does it take to activate this “spark?” If life is difficult and potentially impossible to produce on Earth, then it had to have originated somewhere. Aside from religious opinions, the next obvious scientific mechanism to consider is panspermia.
Evidence of the possible arrival of life from beyond our planet may actually exist, but the concept is hotly contested. In 1996, a meteorite from Mars found in the Antarctic created excitement when scientist announced that it contained microfossils of Martian life. Other scientists disagreed and argued that the fossils were actually formations resulting from natural processes. A December 2014 article in CNET News contained a report on a Martian meteorite that landed in a Moroccan desert in 2011. Researchers who analyzed the organic matter found in fissures of the meteorite found that it was most likely of biological origin based on carbon isotopes.
Many astrobiologists contend that the evidence of spores or single-celled life arriving from space has possibly been found in air samples taken at extreme altitudes which contained cells or spores. These were bacterial in nature and were found at a height of around 40km.
The conclusion of a study of these samples stated, “An extraterrestrial origin of the [isolated material] provides a consistent, if controversial, explanation of our findings. The bacterial material, cultured in the present experiment, and detected earlier through fluorescence microscopy, can be regarded as forming part of the 100 tons per day input of cometary material known to reach the Earth.”
Space is inhospitable, and it seems unlikely that an organism could survive there. However, life has indeed been shown to be able to survive unprotected in space. Bacillus pumilus spores survived the vacuum of space for 18 months in an experiment carried out on the International Space Station. Small invertebrate animals called tartigrades survived exposure to the vacuum of space, as well as its intense radiation during experiments conducted by scientists. The vacuum of outer space and the radiation found there are not complete barriers to the movement of life through the void of space.
Additionally, microorganisms that cling to the side of the spacecraft sent into space by the U.S. have been found to survive and return still alive. This in spite of the high temperatures that develop at re-entry. The potential for bacteria-like organisms to survive high temperature entry into the atmosphere was also studied in a paper by the National Center for Biotechnology Information. The temperatures of the material studies did not exclude the survival of life in meteorites.
Most would agree that we are in our scientific infancy in understanding many things about the universe. For example, scientists indicate that the universe is made up of the matter that we see along with dark energy and dark matter. According to NASA, around 68 percent of the universe is made up dark energy, and 27 percent of the universe is dark matter. The remaining five percent is normal matter that we can see and study. This unknown matter and material does not exist only in the far reaches of the universe either. It exists everywhere and surrounds the Earth, solar system and everywhere else. The disconcerting thing about this is that we do not presently know what dark energy and dark matter are beyond some potential theories. It’s humbling to realize that we have a good idea of what makes up only five percent of whatever surrounds us.
Given this, it’s not unreasonable to think that there are things beyond the Earth that we would not expect and don’t understand. Panspermia does not explain the origin of the very first life in the universe. It’s possible that life was a byproduct of the Big Bang and has always existed in a form that has been able to seed habitable locations throughout the universe since the earliest beginnings. Panspermia has not been seriously considered because it is beyond the conventional framework to which science is accustomed. Evidence is slowly building to support the idea, however. The void of space itself may be teeming with life and may very well hold the answer to the origin of life on Earth.