Each year somewhere between 74 million and 156 million pounds of meteorites impact with Earth, increasing its mass slightly and causing it to be ever more attractive to passing space rocks. But a recent discovery by scientists has made the incredible revelation that these meteorites could have life within them. The meteorites were revealed to not only contain the building blocks for life, but do so in the precise way scientists predicted to validate the "space seed" theory also known as panspermia.
This theory suggests that over time smaller asteroids developed the necessary building blocks for life and eventually dropped to Earth where they found themselves in an ideal place for life to develop. Eventually the environment allowed the ideal circumstances to arise and these building blocks took off, eventually becoming more complex as time went on. Eventually different strains of life began interacting with one another and began competing with one another for food and resources. And so evolution kicked in and the rest is history.
One of the main problems with this theory is no one is quite sure where those first few building blocks came from. In fact, some have suggested the place that would produce the ideal building blocks and the place where those building blocks would thrive are in fact two completely different environments. And so the discovery of these same amino acids in asteroids not only gives us a telling glimpse into where we could have come from, it also suggests that the same might have happened elsewhere.
In recent years the possibility of life on other planets has changed significantly. One of the problems associated with life as we know it on this planet is that life can exist only in certain very specific parameters and astronomers for the longest time were only able to observe significantly larger planets or highly radioactive planets elsewhere in the universe. As a result, it painted a very specific picture of the known universe - one that was overwhelmingly hostile to life. But as we found eventually, smaller planets - and those existing within the goldilocks Zone such as those orbiting Gliese 581 (Gliese 581D) would start showing most - if not all - the known necessary conditions for life.
So if the universe is full of this necessary material for life to form, and there are plenty of viable planets - even a few which have appeared in our incredibly limited field of vision, is it only a matter of time before we come across life that developed elsewhere in the galaxy? Increasingly, the answer is heading toward a resounding yes. But there are still many limitations left unsolved. For example the presence of an atmosphere is one of the necessary prerequisites for life to form as we know it. The gravitational pull of a moon can move forces on the planet's surface in ways conducive to life in ways that would make it increasingly likely. And finally, but not least importantly, we must wonder if there is something on our planet that specifically allowed humans to develop in the way they eventually did, and search for that mysterious X factor as well. This final point would ensure we would not only find life in general on other planets, but in fact an advanced form of life.
