- Despite the incredibly comprehensive study of the origins of life on Earth, we still don’t know exactly how the first life forms of our planet came to be.
- It is possible, many scientists say, that life on Earth originated elsewhere.
- Right now, our neighbor Mars is the prime candidate for a source of life that Earth has sown.
How did life on earth begin? It seems like such a simple question, but because of the billions of years that have passed since the first life forms began doing their thing on our planet, we just don’t know the answer. Life on our planet may have originated here, but it is just as likely to have originated elsewhere, such as Mars.
The scientific concept that life could spread organically from one planet to another is called panspermia, and it’s nowhere near as wild as it might sound. We already know that rocks from Mars have reached Earth because we found them here, but if ancient Mars had life, what are the odds that life on Earth is a direct result of life forms being snatched from Mars? and accelerated towards Earth?
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We cannot prove that panspermia ever happened. Earth is the only planet that we know has ever been alive, so we cannot know whether it is a valid theory, and furthermore, whether panspermia is responsible for the fact that we are all here today. In a recent interview with Vice, Harvard astrophysicist student Amir Siraj offers a very high level overview of how panspermia can occur and the different ways in which life can seed to other planets or maybe even other star systems.
The events that would cause a planet like Mars to send life to Earth are actually very simple. A strong impact from an asteroid hitting the surface of a life-rich Mars could send rocks into space. Some of those rocks could eventually end up on a collision course with Earth and, if those rocks contain microbial life, those tiny life forms could potentially survive impacting Earth, littering our planet with life.
Since we have already found bits of Mars on Earth, we know that this kind of interplanetary material exchange is indeed taking place, but we cannot know for sure whether Mars ever had life, let alone whether that theoretical life went to Earth or not.
Some more extreme theories of panspermia suggest that it may be possible for objects to scour one planet’s atmosphere, pick up some microbes while flying, and fly out of one solar system and eventually arrive at another. If that microbial life survives the journey and the rock hits a habitable planet in another system, life can spread in a similar way.
At this point, all of this remains completely theoretical, but that could eventually change. When we find microbial life on Mars or evidence of past life, we have to ask whether that life is really our ancient ancestor, or whether life developed on both Mars and Earth within the same few billion years.
Mike Wehner has spent the last decade reporting on technology and video games, covering the latest news and trends in VR, wearables, smartphones and future technology. Most recently, Mike worked as a Tech Editor at The Daily Dot, appearing in USA Today, Time.com and numerous other web and print outlets. His love of reporting is second only to his gaming addiction.