People always ask me about “aliens” (which they mean the bug-eyes greys that haunt book covers worldwide). Those are fictional. The stories of the grey aliens and stories of medieval demons are nearly identical; just a story passed down when people don’t understand science. However much I want those to be true, they aren’t. I absolutely think that it would be improbable for life to not exist outside of Earth. Since most of life on Earth is microbial, we can reasonably expect that when we search for life outside the biosphere, we are looking for bacteria or protists.
We used to think that liquid water in the solar system was rare, that only Earth had that special formula. It now appears that gravity, geology, radioactivity and antifreeze chemicals like salt and ammonia have given many “hostile” worlds the ability to muster the pressures and temperatures that allow liquid water to exist. And research on Earth has shown that if there is water, there could be life. And by life I mean microbial life.
This is a meteorite from Mars called Allan Hills 84001, found in 1996, that contains what appears fossilized bacterial life forms. After 20 years of analytical research with increasingly more advanced tools, the team decided that, “None of the original features supporting our hypothesis for ALH84001 has either been discredited or has been positively ascribed to non-biologic explanations.” In other words, they can’t disprove the claims, nor can they produce similar features using non-living compounds. There are so many more quirks to this Martian tale, but those are stories for a different day.
You know how some people are so stupid about bacteria (like, “Ew! Bacteria? Gross!”). Obviously, each of our cells is outnumbered 10 to one by bacteria living on and inside us. They help us digest our food and a whole host of other things (no pun intended). In the early 1900s, scientists discovered that each person belonged to one of four blood types. Now they have discovered a new way to classify humanity: by bacteria! Each human being is host to thousands of different species of microbes. A group of scientists now report just three distinct ecosystems in the guts of people they have studied. They are calling them enterotypes.
They couldn’t find a connection to race, sex, weight, health or age. They are now exploring other explanations. One possibility is that the guts, or intestines, of infants are randomly colonized by different pioneering species of microbes.
