Alle Dinge sind Gift, und nichts ist ohne Gift; allein die Dosis macht, dass ein Ding kein Gift ist.
All things are poison, and nothing is without poison; the dosage alone makes it so a thing is not a poison.
Paracelsus, 1538
The word for poison in German is Gift?!
The word has been used as a euphemism for “poison” since Old High German, a semantic loan from Late Latin dosis (“dose”), from Ancient Greek δόσις (dósis, “gift; dose of medicine”). The original meaning “gift” has disappeared in contemporary Standard German, but remains in some compounds (see Mitgift). Compare also Dutch gift (“gift”) alongside gif (“poison”).
I’d argue gravitational force isn’t lethal. As long as you don’t arrive at whatever is pulling you & the gradient of gravity doesn’t change across your body length. You could be perfectly fine (for a while) orbiting a black hole at enormous speeds (assuming you don’t collide with matter in the accretion disc.
I’d argue against that. For one thing it is impossible to imagine a situation where there is no change in the gravitational gradient across your body over time. Your orbiting a black hole situation is a perfect example of a situation where the gradient alone would tear you apart. The conditions you’ve specified are tautological. There’s no way to maintain a zero gravitational gradient while also simultaneously having extremely high gravitational field. The two are mutually exclusive in any conceivable scenario.
It’s like saying a human being in a hypersonic wind stream won’t necessarily hurt you, burn you alive and rip you to pieces (not necessarily in that order) as long as there is no turbulence and you have a sufficient boundary layer – but you’re a non-aerodynamic human body in a hypersonic wind stream, so of course there will be turbulence and the boundary layer will not protect you at all, you’re going to die, basically instantly.
Does the change in gravity gradient across your body kill you right now? No? You are currently orbiting the supermassive black hole in the center of the milky way. You and everything else in the milky way aside from a few intergalactic objects just traveling through.
I am not an astrophysicist, but I do understand basic physics.
Can’t help you if you don’t understand what “ideal cases” are, when the real world examples are not practical to describe the underlying principle. The point is: gravity doesn’t kill you, no matter how high the absolute.
Arguably, in a perfect gravitational field, you could even be accelerated at insane speeds without experiencing discomfort, because each atom of your body would be experiencing the same acceleration.
I think General Relativity is based on the idea that a frame of reference that’s in freefall is equivalent to one that in a gravity free region of space (at least that was one of Einstein’s Gedankenexperiments that led him to his theory of GR).
Having said that, in reality a sufficiently strong gravitational field will cause a tidal effect, which will crush you along one axis and pull you apart along another.
There was definitely something like that - I am not sure if free-fall and being accelerated in a gravitational field are the same though. It may be that GR is talking about moving along lines in space-time that have the same gravitational potential (orbits), and moving across potential lines counts as an accelerated frame of reference in which you wouldn’t observe the same as in a reference frame moving at constant speed.
Wouldn’t a high enough force cause the gradient of gravity to differ?
Unless I misunderstood how that works. I’m picturing a downed powerline that causes large differences in voltage across the ground, which is why you are supposed to shuffle instead of taking a normal step. Would a high enough gravity cause a harmful gradient across the length of a human body?
Like if you were free falling into a black hole, the gravity forces would rip you to shreds long before you ever actually impacted anything because the difference in the force of gravity on the parts of your body that are closer to the black hole and the parts of your body that are farther away are enough to shred you like lettuce.
Gradient: the change of a value (here: gravitational force, or rather: potential) over a reference variable (here e.g. the length of the body)
No, the absolute value of the gravitational force does not matter for the gradient. Gravitational force (potential) is proportional to the inverse distance squared from the center of mass that exerts the gravitational potential. If your distance from the object R is large enough, then the gradient of gravity across the length of your body is negligible:
In the worst case, with your body length being s, the gravity at the part of your body closest to the center of mass pulling you would be: F_max = F_min * ( R^2 / (R-s)^2 ), and with s << R, this becomes F_min, the force at the part of your body furthest away from the mass pulling you in.
This becomes problematic when you get “too close” to the body in question - and where too close begins, depends indeed on the absolute force. But for each black hole, there’s a safe distance at which you could fall around it, assuming no other factors killing you (like intersteller particles, or an accretion disc)
I thought about this a bit and concluded that it only applies to physical materials and forces.
For example: There certainly are lethal ideas, but most of them are not, and much like bosons they can overlap, so filling a person with multiple copies of the same (benign) thought has a diminishing effect.
But yeah, anything physical has a lethal concentration.
howrar@lemmy.ca 1 year ago
Not just about. Literally everything is lethal at a high enough concentration.
Duranie@lemmy.film 1 year ago
LD50’s are fun!
en.m.wikipedia.org/wiki/Median_lethal_dose
ilex@lemmy.world 1 year ago
The word for poison in German is Gift?!
Well that’s dumb.
BearGun@ttrpg.network 1 year ago
“gift” means both “poison” and “married” in swedish. languages are fun :)
raspberriesareyummy@lemmy.world 1 year ago
I’d argue gravitational force isn’t lethal. As long as you don’t arrive at whatever is pulling you & the gradient of gravity doesn’t change across your body length. You could be perfectly fine (for a while) orbiting a black hole at enormous speeds (assuming you don’t collide with matter in the accretion disc.
cecilkorik@lemmy.ca 1 year ago
I’d argue against that. For one thing it is impossible to imagine a situation where there is no change in the gravitational gradient across your body over time. Your orbiting a black hole situation is a perfect example of a situation where the gradient alone would tear you apart. The conditions you’ve specified are tautological. There’s no way to maintain a zero gravitational gradient while also simultaneously having extremely high gravitational field. The two are mutually exclusive in any conceivable scenario.
It’s like saying a human being in a hypersonic wind stream won’t necessarily hurt you, burn you alive and rip you to pieces (not necessarily in that order) as long as there is no turbulence and you have a sufficient boundary layer – but you’re a non-aerodynamic human body in a hypersonic wind stream, so of course there will be turbulence and the boundary layer will not protect you at all, you’re going to die, basically instantly.
raspberriesareyummy@lemmy.world 1 year ago
Does the change in gravity gradient across your body kill you right now? No? You are currently orbiting the supermassive black hole in the center of the milky way. You and everything else in the milky way aside from a few intergalactic objects just traveling through.
I am not an astrophysicist, but I do understand basic physics.
themeatbridge@lemmy.world 1 year ago
You argue that it isn’t, and then provide several examples where it is.
raspberriesareyummy@lemmy.world 1 year ago
Can’t help you if you don’t understand what “ideal cases” are, when the real world examples are not practical to describe the underlying principle. The point is: gravity doesn’t kill you, no matter how high the absolute. Arguably, in a perfect gravitational field, you could even be accelerated at insane speeds without experiencing discomfort, because each atom of your body would be experiencing the same acceleration.
jon@lemdro.id 1 year ago
I think General Relativity is based on the idea that a frame of reference that’s in freefall is equivalent to one that in a gravity free region of space (at least that was one of Einstein’s Gedankenexperiments that led him to his theory of GR).
Having said that, in reality a sufficiently strong gravitational field will cause a tidal effect, which will crush you along one axis and pull you apart along another.
raspberriesareyummy@lemmy.world 1 year ago
There was definitely something like that - I am not sure if free-fall and being accelerated in a gravitational field are the same though. It may be that GR is talking about moving along lines in space-time that have the same gravitational potential (orbits), and moving across potential lines counts as an accelerated frame of reference in which you wouldn’t observe the same as in a reference frame moving at constant speed.
otter@lemmy.ca 1 year ago
Wouldn’t a high enough force cause the gradient of gravity to differ?
Unless I misunderstood how that works. I’m picturing a downed powerline that causes large differences in voltage across the ground, which is why you are supposed to shuffle instead of taking a normal step. Would a high enough gravity cause a harmful gradient across the length of a human body?
Bizarroland@kbin.social 1 year ago
The term spaghettification comes into mind.
Like if you were free falling into a black hole, the gravity forces would rip you to shreds long before you ever actually impacted anything because the difference in the force of gravity on the parts of your body that are closer to the black hole and the parts of your body that are farther away are enough to shred you like lettuce.
raspberriesareyummy@lemmy.world 1 year ago
Gradient: the change of a value (here: gravitational force, or rather: potential) over a reference variable (here e.g. the length of the body)
No, the absolute value of the gravitational force does not matter for the gradient. Gravitational force (potential) is proportional to the inverse distance squared from the center of mass that exerts the gravitational potential. If your distance from the object R is large enough, then the gradient of gravity across the length of your body is negligible: In the worst case, with your body length being s, the gravity at the part of your body closest to the center of mass pulling you would be: F_max = F_min * ( R^2 / (R-s)^2 ), and with s << R, this becomes F_min, the force at the part of your body furthest away from the mass pulling you in.
This becomes problematic when you get “too close” to the body in question - and where too close begins, depends indeed on the absolute force. But for each black hole, there’s a safe distance at which you could fall around it, assuming no other factors killing you (like intersteller particles, or an accretion disc)
ThirdWorldOrder@lemm.ee 1 year ago
The first part of the question asks what is safe in small amounts
davidgro@lemmy.world 1 year ago
I thought about this a bit and concluded that it only applies to physical materials and forces.
For example: There certainly are lethal ideas, but most of them are not, and much like bosons they can overlap, so filling a person with multiple copies of the same (benign) thought has a diminishing effect.
But yeah, anything physical has a lethal concentration.
PostmodernPythia@lemmy.world 1 year ago
I love nerds.