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Navvana t1_j2820m2 wrote

The answer will depend on how far back you want to go.

Way back with Arisistotle it was basically thought that the “earth” element pulled things towards the center of the universe.

From there many individuals separately began to describe this attractive force that pulled stuff to the earth, and even began to calculate/quantify it.

So it’s not really true that Newton came up with the idea of a “gravitational force” in the sense of some sort of law of nature that made apples fall from trees.

What Newton did was develop a law of universal gravitation that could actually be applied to everything. At least everything up until we started seeing relativistic effects.

His mathematical equations/proofs showed that the same force that made apples fall to the earth was what made the planets move, and that the force was at least correlated with mass. Prior to Newton the two were not unified, and many thought they were separate phenomena.

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T1N7 t1_j28futz wrote

I'd also add that people more versed in metaphysics thought all things tend to move to their natural state, which for things being on earth

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TychaBrahe t1_j29hevp wrote

To expand on this, Aristotle believed that all matter was made up of a mix of four different elements: fire, air, water, and earth; in that order. Things wanted to return to their natural place.

The Sun was above the air of the sky because fire was naturally above air. If you created a fire here on Earth, one of the effects was that sparks would rise, and this was seen as the element fire naturally seeking its place above the air.

Rain was element water that got above element air, and wanted to be beneath it. That's why rain fell. Your average objects, like a rock or a piece of metal, would fall because they were made of element earth. Thus they were naturally attracted to earth, and if they find themselves unsupported in element air, they will naturally fall.

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atomfullerene t1_j29qpvf wrote

This is one of several reasons the heliocentric theory took so long to catch on, despite being proposed as far back as the ancient Greeks. The existing conception of physics described above fits quite nicely with a geocentric universe, but doesn't mesh at all with a heliocentric theory. You need a whole new sort of physics (like gravity) to make sense of that.

Incidentally, this also means that Earth's position at the "center of the universe" in the geocentric theory wasn't quite as special as we sometimes think today. The earth was at the center, but the center wasn't necessarily seen as the "best" spot, it was more at the bottom of the cosmic pile, the place where all the dirt falls down to. The outer regions, aka the heavens, were often considered the "best seats" (due to their association with, well, heaven). There was often thought to be a "Fifth Element" (yes, the movie got its name from this idea) that inhabited the highest reaches away from earth and was what the stars and planets were made of.

This also means that the movement of the planets was seen as a fundamentally different sort of thing than the movement of apples. Apples were following the nature of earth, going toward the center. Planets were following the nature of their element, moving in perfect, ordered circles in the heavens.

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BillBigsB t1_j2bipfx wrote

It was in Aristotles lifetime that the first greek was born to propose a heliocentric theory. I suggest you learn more about greek physics before you profound such errors.

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compwagon t1_j2avd43 wrote

If you suspend what we obviously know, that was actually a very cleverly thought out theory. Really interesting to see how people thought and understood things back then.

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cristiano-potato t1_j2b38nd wrote

Seems like it’s a good example for how a totally wrong conceptualization of a situation can still be very congruent with what you can observe easily

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Mr_Brightwell t1_j2b3q0o wrote

Yeah, and if we have done it once we are probably doing it again, right now.

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kuroisekai t1_j2bgu7c wrote

Very very true. Nowadays many promonent physicists stake their careers on stuff like String Theory or Multiverse Theory, when neither have any direct evidence to back these up, other than "the math makes sense". That's why it's very refreshing when you hear scientists in places like CERN say "we hope we're wrong because that means we get to make new physics". And also why this year's Nobel Prize for Physics is a big deal: they managed to prove Einstein wrong as well.

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T1N7 t1_j29k8b2 wrote

Oh wow thanks! I always wondered why the natural state of stuff was considered near the ground...

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incarnuim t1_j2c64d5 wrote

Also in this conception, water is above earth, so if you drop a stone in a lake, it will seek the earth. But wood is made of air and fire (and a little tiny bit of earth), so it floats. And burns....

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Verlepte t1_j28vn4g wrote

The bit about Aristotle is not quite correct, that's a very Newtonian way of describing his theory. He was working within a Teleological framework, basically the idea that everything has a goal, an essence, that it's moving towards. Part of this is that like things move towards like things, so it's the 'earth' element in things that makes it move towards the earth, not due to some force but because that's where it's goal is.

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Denziloe t1_j29kihg wrote

To elaborate. Aristotle believed that the earth element strove to be at the centre of the universe, water strove to be above earth, air above water, and fire above air. There was no concept of a force pulling everything together as in Newtonian physics.

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obnoxiousbutquiet t1_j292t6w wrote

While I do see the philosophical distinction, this is still very Newtonian to me. Very interesting.

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Verlepte t1_j2az2se wrote

It's fundamentally very different. In Newtonian physics there's an attractive force that causes for instance a rock to fall down to the earth. In Aristotelian physics there's no attractive force, but the rock strives towards the earth and therefore falls down towards it.

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seriousnotshirley t1_j28zmgk wrote

There's two things Newton did here, one was understanding that things accelerate under a force. For the apple to start falling there needed to be some force acting on it and that force was equivalent to the mass of the object times it's acceleration, which, it put another way, was that the apple was accelerated towards the earth by an amount equivalent to the force acting upon it divided by it's mass.

The second thing was gravity. So what force was acting upon that apple? It was the force of Gravity! That force was proportional to the masses of the two objects divided by the distance between them squared.

​

Side note: notice that when you take the force of gravity and divide it by the mass of the object being acted upon, the apple, to find out how it's accelerated, the mass of the apple will cancel out by division; and so it doesn't matter of the gravity of earth is acting on apples or bowling balls, the force is the same!

The first is important because under the Teleological framework things had an innate motion towards some ideal state and from this we can start to appeal to faith to divine what things want to move towards. Under Newton's laws things only move when acted upon by some force being applied to them. The second is important because it defines gravity of massive objects as the force that moves objects towards the ground on earth and what keeps the planets orbiting the sun and the moons orbiting their planets rather than the hand of God or some other ideal. Why is this important? It means we can predict natural phenomena rather than appealing to prayer. We can predict the tides, and predicting the tides was really really useful in an age where shipping was economically critical.

Before Newton there were some attempts to predict the tides but they didn't have anywhere near universal success and so people might as well appeal to faith or superstition as they might anyone else who is only sometimes correct. Newton was reliable in his prediction to a point it became hard to ignore... but we've wandered off OP's question here.

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Jonny0Than t1_j296li6 wrote

>it doesn't matter of the gravity of earth is acting on apples or bowling balls, the force is the same!

Think you swapped a word here: the *acceleration* is the same - the force is proportional to mass.

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GrinningPariah t1_j298ni7 wrote

Newton wasn't the first to think the Earth was pulling on the apple. He was the first to realize the apple was pulling on the Earth too.

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Denziloe t1_j29kt82 wrote

And that the same force from the Earth was pulling on the moon. His was a theory of universal gravitation. Universal is the important idea.

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LazerWolfe53 t1_j29gcs6 wrote

Yeah. People figured out "earth pulls stuff". He blew it open to "all stuff pulls all other stuff"

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arcosapphire t1_j28wypu wrote

> His mathematical equations/proofs showed that the same force that made apples fall to the earth was what made the planets move

I wouldn't say "what makes them move"--he understood momentum, and what gave planets their momentum is not defined by his gravitational theory. (I would assume he described the initial velocity as divinely created.) Gravity just describes why they orbit.

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staroura t1_j292tzt wrote

Isn’t Einstein’s gravitational theory more accepted now?

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DegenerateEigenstate t1_j297g5q wrote

General Relativity is regarded as the accurate description and cause of gravitation, but the Newtonian formulation is a very good approximation in most cases.

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[deleted] t1_j29i2x1 wrote

[removed]

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wasmic t1_j29tljm wrote

This isn't correct beyond a surface reading.

We know that quantum mechanics and general relativity cannot both be correct, because they conflict with each other.

But more probably, it seems like both are incomplete. There's a lot of unexplained stuff in space too - like dark matter, where some people propose a modified set of gravitational laws to explain motions instead introducing dark matter (which has never been measured). Very theoretical of course.

But we also have been completely unable to add any sort of gravity to quantum mechanics at all. The accepted models of QM more or less ignore gravity entirely because its power is negligible at quantum scales anyway.

What we know is that the extremes - extremely tiny scales, extreme velocity, extreme gravity - has complicated laws of nature, which happen to trend towards simpler forms as conditions approach everyday life. But you can't really conclude anything else based on that.

> Some physicists are questioning if General Relativity is totally accurate. It's a great approximation, but Quantum Theory may be an even better description of the Universe.

This is just nonsense. The two theories are describing entirely different things. Describing "the entire universe" is outside the scope of general relativity, which only describes gravity. Meanwhile, describing gravity is outside the scope of most Quantum Theory, and those that do include gravity lead to inconsistencies - or even worse, contradictions.

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whatkindofred t1_j2baxsi wrote

What’s the difference between inconsistencies and contradictions?

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DegenerateEigenstate t1_j2a1tty wrote

I would be careful taking these kinds of ideas too seriously. This starts to get too close to metaphysics for my liking, and I don't believe any physicist genuinely believes or could verify this if they wanted to. It's akin to quantum woo in my mind.

Also, as the other poster already said, saying "quantum theory" is a better description of the universe is nonsense; they describe entirely different things. Although it is no secret they are incompatible as of now, this just indicates one or both may be incomplete but not entirely wrong.

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Dd_8630 t1_j2bsp18 wrote

>Some physicists are questioning if General Relativity is totally accurate.

No physicist has ever thought that GR is totally accurate, not even Einstein. We've known from the very beginning that GR and QM are incomplete.

>The simulation has limits so the extreme edges "break" the rules.

What rules does it break? The universe is under no obligation to obey human intuition.

>It is possible the universe is the same way...

That's absolutely nothing to suggest that it is. We humans evolved to have an intuitive understanding of the world we interact with; therefore, we should expect physics to diverge from our evolved intuition when we go beyond humans scales - namely, the very small, very large, very vast, very hot, very rarefied, etc. Go beyond STP and scales of metres and seconds, and we should expect to hit counterintuitive results.

It would be more indicative of a contrived simulation if we didn't encounter edge weirdness.

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antiiltal t1_j29qt8n wrote

Well yes and even a little bit humoristically according to relativity there is no real gravitational force existing between objects. Mass is just bending and curvature of the spacetime. So the bigger object the more curvature on the fabric of spacetime and smaller objects fall in to them, because of the curvature. In the end Newton was actually wrong with gravitation.

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FeynmansMiniHands t1_j29jcmg wrote

It's important to note that Newton also defined the modern concept of 'Force'. The concept does not appear in preNewton works.

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chemistrystudent4 t1_j29uvkr wrote

The man didn’t have to come up with the idea/notion of some gravitational force. It was the formulaic derivation and idea that multiple seemingly-unrelated phenomena were indeed governed by the same thing which made him a straight thug.

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_AlreadyTaken_ t1_j29gy95 wrote

He put numbers to it which required developing calculus and building on Galileo's and Brahe's/Kepler's observations.

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CaptainHunt t1_j29ttz3 wrote

The important thing is that he wasn’t trying to work out why apples fell from trees, if there is any truth to the legend at all, he was just inspired, by an apple falling, to come up with gravity.

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_zoso_ t1_j2a3ctr wrote

More people should read “The Structure of Scientific Revolution” by Kuhn. There really are no sudden breakthroughs in science, at least as the general public tends to understand, it’s always some kind of gradual change or a collective buildup of many ideas over periods of time.

When it happens, it’s always evolution. In hindsight the stories are always told like it’s some sudden new idea.

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OldWolf2 t1_j2ajhig wrote

I'd like to add that Newton and his contemporaries founded modern science -- the worldview that there is actually an objectively correct explanation for natural phenomena, and we can work on finding that out through thought and experimentation.

You will have noticed there are still many people today who don't hold that worldview, sadly; but in Newton's time and earlier, this described pretty much everyone outside of a select few, who were often considered heretics, witches, that sort of thing for their troubles .

Truth was what the church said it was and most people didn't have the concept of thinking about why apples fall, they just did. A large part of what Newton is remembered for is the notion of investigating this kind of thing at all .

(NB. My comment is Eurocentric like the question ; attitudes may have differed in other civilization centres ).

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Ok-Development-8238 t1_j2annr5 wrote

The idea that something falling in a straight line/perpendicular to the earth is the same force that keeps the moon running parallel to it…still so surprising to me that someone (or multiple people) realized that

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Grinagh t1_j2bxeza wrote

Newton actually saw a limitation of his theory in the motion of mercury since it requires relativity to explain its motion.

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daywalkker t1_j2chll5 wrote

How profound an effect would simply giving a modern physics textbook to Newton be?

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mayonnace t1_j2b0bry wrote

>“earth” element pulled things towards the center of the universe

Actually, in a sense, that seems correct. I don't know much about this stuff, but it sounds like, if it wasn't the mysterious expanding force, all the matter might have a tendency of pulling each other back into the origin of the universe.

Sometimes I wonder how those ancient Greek philosophers predicted so many things. I guess we owe them a lot, and also the Renaissance people, who I heard saved many writings from those ancient times. The whole science sounds like built on them.

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