The Second Most Astounding Fact

“The Universe is within us”

Alright, I can’t compete with Neil deGrasse Tyson’s fact for #1. But, I do know the second most astounding fact. There is a biological universe within us. Well, more like an ecosystem. A planet. Where interplanetary travel and colonization are possible. I’ll explain.

Lets consider “you” the planet. And by “you” I mean the ~30 trillion cells that you are comprised of that have “your” DNA- the cells that make you “you.” Now, your planet has many inhabitants that aren’t “you.” Entire communities that have colonized different parts of your body and work in harmony (synthesizing vitamins, aiding in digestion, etc.) with the planet they live in. In fact, at any given time, your body has about 10 times more foreign bacterial cells within it than its own cells (bacterial cells are much smaller than your own cells)***. And, on top of this, there is another order of magnitude of viruses that inhabit us (or our bacterial flora) for every bacterium.

***[Update: Other research suggests the number of bacterial cells within our bodies may be of the same order as our cells.]

Sometimes alien species invade our planet and (if our own immune system defenses aren’t fighting well enough) we combat them with antibiotics. However, antibiotics don’t discriminate against friendly and unfriendly bacteria, and can annihilate our friendly gut bacteria– leading to digestion issues, or even the recolonization of the gut with unfriendly species. (I’ll save fecal transplants for another post). One instance of this recolonization that has been receiving some press time recently has been of a homebrewer who had a population of Saccharomyces cerevisiae call his gut home. This single celled fungus, also known as “brewers yeast”, plagued the man by, well, doing what it does normally- metabolizing carbohydrates and producing ethanol as a waste-product. Not surprisingly, the condition is known as Auto-brewery syndrome.

Anyway, I always thought the existence of a microbiome within all of us was a really cool and astounding fact. At every instant of your life, there are hundreds of trillions of individuals living their lives within you. Awesome.