You know that feeling when you go over a hill fast in a car or in a roller coaster? According to BBC Science:
"In that moment, your organs don’t ‘fall’ at the same rate as the rest of your body. You then experience a moment of near-weightlessness, a bit like what an astronaut experiences in space.
Your intestines and stomach are loosely suspended, so when your body quickly moves downwards, they lag slightly behind.
The nerves around these organs sense the alarming, potentially harmful, change to your position and send a signal to your brain, creating that weird stomach-dropping feeling."
That last (bolded) bit caught my attention. Any kind of thing like that is a product of years of evolution, right. So when, before the advent of fast moving vehicles, would a body be subjected to this sensation? Enough so that a defensive mechanism would develop?
The obvious situation when you’d feel such a sensation is when you’re falling. Like out of a tree or off a cliff. There’s often not a lot you can do in such a situation, but the instinctual reaction is apparently to tense your muscles, throw out your arms, etc. to brace against the impending impact.
When we first became able to accelerate quickly, and evolved the ability to sense that acceleration. That also meant we had the ability to detect rapid descent or free fall, even if we had little use for it at the time. This isn’t a specialized “falling sense”; it’s your ability to detect the acceleration of your body telling you that something is Weird and Wrong.
Maybe. I’ve fallen out of and off of a lot of things and don’t remember feeling it. But it could be. If so, that means it developed long before we were human and still living in trees.
The Moro Reflex is a reflexive grasping/hugging move that infants display when startled. Falling certainly could be startling. The guts thing could be a variation on the Moro Reflex.
I’ve heard that some relatively-common poisons can produce that feeling, which is why, when prolonged, it leads to nausea. “Maybe I ate something poisonous! I’d better throw it up just to be sure.”
It’s funny, I don’t encounter that sensation when I propel myself into a fall (or dive). The effect must be located in the brain as much as the gut. And it’s almost always on carnival rides; I don’t recall it with the accidental free falls I have endured.
I’m no help in explaining the purpose of them, but we just called them "Thank you, Mom!"s.
Mom knew all the little hilly areas along our drives that would produce the sensation and would speed up a little bit to make them more exciting. To which we would yell…
The anti-gravity plane flights have to fly in a parabolic curve to get the weightlessness working. I always figured those humps you drive over were, if you were lucky, also close to parabolic. And when they aren’t, which is most often, we don’t get that feeling.
Your innards are not reacting to zero G. They are reacting to other than 1G. 3/4ths or 1/2 of one G is plenty to trigger stomach unease in susceptible folks.
Yep. A pilot friend used to do those in his Cessna 172. Not as long and as extended as on the Vomit Comet, where astronauts train, but the same effect. I well remember when my pack of smokes floated up out of my shirt pocket and hit the ceiling, before falling back into my lap when we resumed level flight.
ETA: We did not float; we were all safely belted in.
There’s another curious phenomenon that is sometimes associated with free fall that I’ve mentioned before, which I experienced back in the days when I was foolish enough to leap out of airplanes and hoped that my parachute would open. One might ask if I experienced that stomach-churning feeling in free fall, and the rather remarkable answer is that I don’t remember, inasmuch as I don’t remember anything about the free-fall portion of my jumps, though I distinctly remember sailing under the parachute and steering it and the landings. But the free-fall portion is a total blank.
The theory seems to be that falling out of an airplane is so intrinsically terrifying that the mind refuses to register it. There may be a memory of it in there somewhere, but later the brain goes “that never happened, nope, nope, let me just erase that memory for you”. And that remained true even on a jump where, due to the pilot chute failing to catch the air stream for longer than usual, my free fall was longer than usual. Still remember nothing until the point of parachute deployment.
Of course once one gets acclimatized to it, as experienced jumpers eventually do, you’re very much aware of everything and that’s when you can do tricks like formation jumping. But it’s very different for beginners.
That aligns with the assertion that the feeling is caused by the organs not falling in sync with the rest of the body, since in free fall they would be all falling together, whereas the quote from the BBC about the organs lagging behind would make more sense if you’re on, say, a roller coaster, where your straps are pulling your skin down first before your organs can catch up.
That would mean that a roller coaster car is moving downward faster than an object in free fall would. Since a roller coaster is not powered, how would it do that?
No, I don’t think that’s what @Ludovic meant. I think they just meant that a roller coaster can generate significant G forces both less than 1 G and considerably greater than 1 G, and switch between them quite rapidly.
When one reaches a certain age, one marvels that young’uns actually pay money to be subjected to this!
There was a sudden change in the slope rate on the road from the supermarket to our home when I was a kid. Most of the time, nothing special happened. But once in a while, my father would approach it at the just the right speed and I got that feeling you described. Loved it.
When my kids were little they would ride with me in the mornings so I could drop them off at daycare on my way to work. Our driveway entered the road out of our neighborhood at the top of a small, but rather steep hill. If we had an extra minute or two, I would sometimes turn left instead of right leaving our driveway and go to the cul-de-sac at the end of the road, turn around, and drive back over the hill at sufficient speed to generate that sensation. My kids called that “the WHEEE!! way”.
