I finally got a chance to see Prometheus this weekend and it reminded me why I love both technology and space so much. Without giving too much away for those of you that haven’t yet watched it, one of the more prominent ideas put forth in the movie is that we were created by alien lifeforms that look eerily human in many respects. While I don’t buy into the notion that we were created by other beings (although I do suppose it’s plausible in some respects), I have often wondered what extraterrestrial lifeforms might look like. This is the focus of today’s post. Your input and thoughts are welcome as always.
Occam’s razor would suggest that extraterrestrial lifeforms wouldn’t be quite as different as sci-fi has so often depicted. On the other hand, many scientifically inspired works have long suggested that life on other worlds would be significantly stranger and vastly different than anything found on this planet. For instance, some researchers have depicted alien creatures as somehow silicon-based rather than carbon-based.
Species with silicon structures could theoretically perform respiration functions with nitrogen molecules instead of oxygen-based matter [all of you biologists out there - feel free to correct me if I'm wrong on this account]. This thinking is perhaps particularly creative, but that doesn’t mean that it’s entirely accurate. Hydrogen, carbon and oxygen molecules are found in certain proportions in life on Earth. In The Fitness of the Environment (1913), American biochemist Lawrence Joseph Henderson first stressed the advantages of carbon and water in lifeforms. Henderson was struck by the fact that the very materials needed for life are exactly those that are abundant here on Earth. It remains a remarkable fact that the atoms most useful for life have very high cosmic relevance. Thus, there’s no reason to suggest that life anywhere else is any different. That doesn’t mean it can’t or hasn’t happened. It just means that right now, we don’t know of another way life may have evolved.
Since the search for extraterrestrial life has often focused around planets that vaguely resemble Earth, it seems a bit strange that people have envisioned aliens as so remarkably foreign. While the culture of some distant planet might be shockingly different, the individual beings there might have much more in common with humanity than anyone ever imagined.
Some researchers have suggested that it seems arrogant to assume the aliens are similar to beings on Earth. However, assuming that otherworldly species resemble Earthlings isn’t necessarily arrogant. One might deduce that it’s the most realistic way to answer the question posed in the title of this post. After all, the idea of lifeforms being based around something besides carbon is seemingly outlandish given our current understanding of biology and how life is created.
What do you think? If there are in fact alien lifeforms out there, are they vastly different from us or closer than those most often depicted in literature and film?
Ehrenfreund P, Spaans M, & Holm NG (2011). The evolution of organic matter in space. Philosophical transactions. Series A, Mathematical, physical, and engineering sciences, 369 (1936), 538-54 PMID: 21220279
Ziurys LM (2006). The chemistry in circumstellar envelopes of evolved stars: following the origin of the elements to the origin of life. Proceedings of the National Academy of Sciences of the United States of America, 103 (33), 12274-9 PMID: 16894164
Kerr RA (2012). Planetary science. Homegrown organic matter found on Mars, but no life. Science (New York, N.Y.), 336 (6084) PMID: 22628628
Davies PC (2003). Does life’s rapid appearance imply a Martian origin? Astrobiology, 3 (4), 673-9 PMID: 14987473
Frederick Su (1996). Extraterrestrial life forms examined SPIE DOI: 10.1117/2.6199612.0001