Tidal forces have enough power to literally tear planets and moons apart over millions of years. Which is understandable, because it’s a planet / moon. But humans and our tech do not have that level of durability. Yet we can remain in orbit practically indefinitely with little to no consideration about tidal force being a threat. Why is that?
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Because the gravity acting on us most is Earth’s. The tidal forces we experience aren’t enough to overcome that significantly. If the moon were much closer or if we were closer to the sun, things would be a different story
Tidal forces are significant because of a *difference* in gravitational pull between the parts of an object. A planet can be torn apart by tidal forces if the gravitational force on one side is significantly greater than the other. Since the key factor is this difference in force what matters is the gravitational *gradient*, or the difference in gravitational force over distance. For a very large object there can be a significant difference such as with a planet, but for a small object like the human body we just don’t occupy enough space for there to be much difference between the gravity on one end of our body compared to the other. If we were in an extremely intense gravitational field such as passing by a neutron star then those tidal forces could become a problem on our scale, but for objects that are not extremely compressed tidal forces shouldn’t be relevant on the scale of humans.
Tidal forces can break apart objects that are held together by gravity if they get closer than the [https://en.wikipedia.org/wiki/Roche_limit](https://en.wikipedia.org/wiki/Roche_limit) that is when the tidal force becomes larger than the body gravitational self attraction.
The tidal force will break apart an object quite quickly when it gets within that limit. it can take millions of ears for an orbit to decay so you reach the limit but then it is a quite rapid process.
You are held together by chemical bonds, you are alos quite small so the gradation difference over your body is minimal. On the earth’s surface, you can hand from your hand and do not break apart. Gravity is simply not stong enough to pull you apart even if you are not in orbit.
These are tidal forces you find around regular planets and stars. The tidal force around a black hole can be so large that it will rip a human apart, it is called https://en.wikipedia.org/wiki/Spaghettification
Tidal forces happen when gravity pulls on one part of an object differently than on another. For instance, if a large moon passes closely to a planet, gravity would be pulling on the side of the moon facing the planet more than the side away from the planet, just because the side facing the planet is closer and gravity depends on distance. If the difference in force is large enough, it can potentially tear the moon apart. Planets and moons are also mostly held together by gravity themselves. Gravity is weak compared to the other fundamental forces, making celestial bodies relatively “fragile” for their size.
Humans are both very small and held together mainly by electromagnetic interactions between molecules in our bodies. Two meters or so of distance between our heads and feet isn’t going to change the force of gravity much around most celestial bodies, so tidal forces are going to be very small, and too weak to cause any physical damage.
> But humans and our tech do not have that level of durability.
They’re also a lot smaller than a planet. What matters here is strength per size, since the difference in gravity grows with the distance between 2 points. And in that category, humans are a lot more durable than dirt or rock piles.
Tidal forces are caused by gravity and gravity, on the whole, is extremely week. We only see its effects on planet size objects because there is a lot there to be affected. The tidal range (difference between low tide and high tide) can be upwards of like 13 or so feet.
When the Earth is 42 million feet, that is miniscule change. Scaled to a 6′ human body and tidal forces are stretching you out 0.00002 inches. Negligible.
Tidal forces are the effects of gravity of an object being stronger on the part of another object that is closest to it than on the parts of it father away.
Gravity pulls thing together, but its force decreases with distances. Objects closer to the center of gravity get pulled down stronger than objects father away. Parts of an object close to the center get pulled stronger that father away parts. That difference is what makes tides.
If you have strong enough tidal forces it can totally tear a human body apart.
However in most circumstances the difference between the gravitational acceleration of your head and feet is going to be so small that it doesn’t really matter.
Planets and moons are much bigger than people and mostly held together by gravity so tidal forces are much worse on them.
If the moon were to be much closer to the earth than it actually is, the difference between the gravity on its nearside and its farside would be bigger than its own gravity holding it together and it would be pulled apart into a ring like Saturn has.
This distance is called the Roche Limit.
But it only is a thing for objects big enough to be held together by their own gravity.
Humans are not held together by their own gravity. We are held together by our skin and muscles and bones and so on which are mostly held together by chemistry rather than gravity.
Of course if the tidal forces were much bigger a human could also be pulled apart.
So if you ever encounter a singularity don’t get too close to the event horizon or the gravity acting on the part of your body closest to the singularity will be so different from the gravity acting on the part of your body farthest from it that it will pull you apart.
You will die of other things long before that most likely but you still will get ripped apart.
Short version: Big things are susceptible to tidal forces. Small things aren’t. A person is much smaller then a planet ^((citation needed)^) so tidal forces arn’t a concern for us expect in extreme circumstances.
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