A house made of breath

 In the carbon cycle we inhale oxygen (O2) and react it with sugar via the Krebs cycle to made Adinosine Triphosphate--or ATP, the chemical energy that powers enzyme reactions in your body. A byproduct of the Krebs cycle is carbon dioxide (CO2), which we exhale as waste.

 Trees then absorb that carbon dioxide, react it with water and sunlight via the Calvin cycle to knock-off the carbon atom and make sugars with it (photosynthesis, in a nutshell). The byproduct of photosynthesis is oxygen (O2), which it releases to be inhaled by an aerobic organism such as ourselves.

 Trees get their physical mass from the carbon in the air, not from the soil, which means the wood used to build your house and furniture was made out of breath.

Everything that will happen has already happened

 If a universe is said to be "deterministic" it means that everything that happens will happen for a reason. That means any event in that universe can be determined from its base conditions by calculating it mathematically. This means that the entire state of that universe at any instant of time can be represented with a single number. 

 We know that there are an infinite number of numbers (proof: think of the biggest number you can, then add one to it), so somewhere in the population of all numbers must be all of the numbers that describe every moment of time in every possible deterministic universe.

 If our universe is deterministic--and everything we can measure scientifically suggests that it is--then everything that has ever happened and will ever happened has already happened. Every moment of time for the entire universe exists simultaneously, representable as a mere number.

Your relatives make you sick

 The eukaryotes (creatures with a nucleus in their cells, such as humans) were probably formed by a virus invading a prokaryote many millions of years ago, taking up residence there instead of destroying it to make more viruses.

 That means the cold/flu virus you came down with this year was actually your very great-great-great-great-great-great-etc-etc-great uncle.

You're not who you were

 Look at a photograph of yourself when you were a child. Inside that child there was a creature growing that devoured the child, cell-by-cell, decomposing it and using that child's own circulatory system and kidneys to dispose of it.

 After about 18 days, that creature has completely replaced every cell in that child's body, but there is another creature inside of that one which is doing the same thing, completing its insidious task another 18 days later.

 18 days is the average cell replacement rate, with some cells being replaced more frequently (epithelial cells in the gut don't last much longer than 5 days), and others lasting longer (rib muscle cells can last more than 15 years). The atomic turnover rate--where every atom in every cell in your body is replaced--may be as little as 21 days. Not coincidentally, most supermarkets maintain their inventory turnover rate at the same.

 That means the little child in your old photographs of yourself was long since decomposed and pissed down the toilet many 18-day cycles ago.

There are two people living in your skull

 Each hemisphere of your brain is capable of hosting a separate, independent personality. To you, it seems as if there is only one "me" in there, because their activity is coordinated by the cluster of nerves known as the corpus callosum to present the illusion of one mind.

 Some people who suffer from severe epilepsy have undergone surgery to cut the corpus callosum. This halts the seizures and destroys the illusion of unity at the same time. Because while it seems as if they wake up as normal, conscious people with the same personality as they used to have, a careful study of subtle clues reveal that they have been literally cut into two people. The left hemisphere tends to get majority control of the body, while the right hemisphere takes a back-seat ride. Basic movements such as walking are coordinated at a lower level of nerves in the spine, but each hemisphere shows evidence of developing into a separate personality.

 What's worse, they're both operating in oblivion to each other. When scientists covered up the right-eye (and thereby, render the left hemisphere blind) and show a card with the words "WALK ACROSS THE ROOM", the right hemisphere reads it and the patient gets up and starts walking across the room. But when they're stopped and asked "why did you get up?", it's the left hemisphere that takes control of talking, and the patient says "to get a can of soda." Given inexplicable actions by the right hemisphere, the left side just made something up and believed it.

 A hypothesis called Bicameralism, posited by Julian Jaynes in 1976, goes as far to suggest that thousands of years ago the separation of hemispheres was even more severe, and that one side spoke to the other side as a disembodied voice that was interpreted as a muse or a god. Jaynes proposes that this explains the lack of introspective dialogue (the character talking about his own thoughts) in ancient writings such as Homer's Iliad and the old testament. The right hemisphere would suggest actions that the left hemisphere obeyed, and that the left hemisphere would imagine whatever it wanted as the right side's motivation--not unlike what we see in patients who've had surgery to separate the two today.

Think it's gross to eat insects? You're a hypocrite

 There's nothing wrong with earthworm soup or beetle cookies. Some cultures eat barbecued grasshoppers as a delicacy. So your westernized palette decides that's gross and you can't imagine how anyone could eat that? What if I was to say that:
  • we drink the mammary ejaculations of female ruminants who regurgitate their lunch and chew on it some more before swallowing it again and turning it into "milk"
  • not content with that, we will let bacteria fester in this milk for a few weeks and eat the result. Depending on the bacteria and grade of milk, we call the result "sour cream", or "cheese" or "yogurt"
  • when that ain't good enough either, we let veins of mold grow in it for a while more to produce "blue cheese"
  • we puff up our carbohydrates with the farts of billions of tiny organisms that are collectively called "yeast"
  • we also willingly drink the concentrated piss of that yeast, which is a poison called ethanol
  • in the process of making ethanol, we might add some flavor by letting cooked rice go moldy for a few days. The mold is called "koji kin" and the result is called "sake"
  • we devour the unfertilized embryos of flightless birds that--due to modern farming methods--cannibalistically dine on the rendered remains of their own kin
  • we mince up the organs of an animal and stuff it into its own intestinal tube, call it "sausage" and serve it with rotten cabbage that we call "sauerkraut"
  • when we can't get all the meat off a dead bird with an ordinary knife, we crunch up the body and blast it with steam, squish the mush through a sieve and roll it into "nuggets" and "slim jims"
  • and when the meat of a dead cow has gone too rancid we grind it up, zap it with concentrated urine (ammonia) and serve it as a "hamburger"
 We really shouldn't worry about the origin of our food as long as it doesn't kill us. After all, most of it will actually get digested by the swarms of bacteria who live in your gut and comprise 90% of what you leave behind in the toilet.

The good news: there is a human who is actually, physically immortal. The bad news...

...the part of her that thought and talked and walked died in 1951, and the immortal part of her is a line of cancerous cells harvested from her cervix in a segregated ward of Johns Hopkins university hospital. For Henrietta Lacks was a black woman who went to her doctor one day with blood spots in her underwear that led to a diagnosis of papillomavirus induced cervical cancer. The cell sample taken from her had the unusual qualities of biological immortality and the ability to reproduce indefinitely outside of its host--something never before seen.

 Because these cells were human they have been since used to develop medicine such as the polio vaccine. Some of the original cells harvested from Mrs. Lacks in 1951 are still alive today, and there's no reason why they couldn't still be alive a thousand years from now.

Everything you see is a product of your imagination

 Most of the fibers in the optic nerve carry signals from the brain to the eye, not from the eye to the brain. Your retina is just part of your brain that has been extruded forward and smeared over the back of your eyes, and what your brain is doing--in order to see--is program the retina to be sensitive to patterns that the brain expects to see. What gets sent back are very simple signals along the lines of "yep"... "nope"... "darker"... "Movement!!"

 You can see because your brain is methodically stepping through dozens of hypothesis every second and testing them to find out if they agree with the patterns of light entering through the eye. This is why you can have a blind spot but not perceive it.

 And that means everything you see is just a product of your imagination (somewhat confirmed, however).

Humans killed a sea

 The Aral Sea, bordered by Kazakhstan and Uzbekistan, was once the 4th largest inland saltwater lake. Then the Soviets started diverting its supply of water for irrigation in the 1920s. As a result, the sea has gradually shrunk until it barely exists today.