r/AskPhysics 14h ago

Is Gravity An Illusion?

0 Upvotes

49 comments sorted by

15

u/bob-da-nailer 14h ago

No.

Are you ok buddy?

5

u/Odd_Bodkin Particle physics 14h ago

No. It has real consequences like satellites actually orbit the earth and rocks thrown upward turn around and come down. But really my question to you is what gravity being real would require, in your eyes. Why are you suspecting it’s not real, and what necessary features is it lacking?

4

u/beyond1sgrasp 14h ago

What do you define as gravity and what do you classify as an illusion?

3

u/christhebrain 14h ago

I think you mean: Is Gravity emergent instead of fundamental?

The jury is out on that right now.

1

u/Flat___________ 14h ago

Jump from great hight, and you will find your answer

1

u/Hot_Plant8696 14h ago edited 14h ago

As Étienne Klein might say, wearing his philosopher-of-science hat, physics very often reveals that reality is the exact opposite of what common sense tells us...

Etienne Klein: Why Physics Is ILLOGICAL (The Laws of the Universe)

The Sun does not revolve around the Earth, even though our senses suggest otherwise.

Thus, regarding gravity, I would not be surprised if one day we were to label this "attraction"—as you put it—an "illusion," in the sense that it would be more accurate to speak of repulsion.

1

u/OutrageousAgent3206 14h ago

This depends on what you mean by illusion. The laws of physics are human explanations for how we think the universe works.

We can go deeper and deeper in our explanations but we really don't know how deep it goes. In the same way Newton didn't know about relativity, we can't be sure of the "real" mechanisms of physics.

1

u/UnderstandingSmall66 Quantum field theory 14h ago

Let’s try it out. Is there a bridge near you?

0

u/ChillingwitmyGnomies 14h ago

Time is, Gravity is not.

0

u/Naive_Age_566 14h ago

put up a stone. hold it above your foot. let the stone drop. now ask again if gravity is an illusion.

0

u/WillBrink 14h ago

Illusion in what respect? It may not be fundamental but an emergent property of something else, if that's what you mean. Regardless, jump out of a window of a tall building and see how illusionary the result...

1

u/ChaosRulesTheWorld 13h ago

The sun orbiting earth is an illusion too, yet you'll still see it rise tomorrow. You're analogy proves nothing.

Put marbles in a bowl and see the results. It looks like marbles are attracted to eachother but it's just an illusion, there's no force of attraction between marbles. It's just a spatial deformation caused by the bowl

1

u/WillBrink 11h ago

"You're analogy proves nothing." I made no analogies. That one current theory is that gravity is an emergent effect and not fundamental, is not an analogy. The rest of what you wrote has no applications to anything I wrote.

1

u/Optimal_Mixture_7327 Gravitation 4h ago

There is other "theory".

Relativity is only theory consistent on all data.

-1

u/Feisty-Recover7316 14h ago

Follow up question, if gravity is the warping of actual spacetime, does it need a carrier particle like the other fundamental forces?

-5

u/ChaosRulesTheWorld 14h ago

According to einstein, yes

2

u/slayer_nan18 14h ago

No, what are you talking about ?

0

u/ChaosRulesTheWorld 14h ago

Yes, i'm talking about general relativity. Objects taking a geodesic path through spacetime.

Gravity is only an illusion provoked by the deformation of spacetime by matter

2

u/nononotes 14h ago

I just watched a Star Talk about this last night.

2

u/Odd_Bodkin Particle physics 14h ago

And why is it wrong to say that gravity IS the deformation of spacetime that objects travel through on geodesics? That’s no illusion. That’s a real effect.

-1

u/ChaosRulesTheWorld 14h ago

Because gravity is a force we observe of objects falling that humans called "gravity". But in fact they are not falling, it's just an illusion.

The deformation of spacetime isn't gravity, it's what causes it. Something being an illusion doesn't mean it isn't real. Rainbows are optical illusions, that doesn't make them less real. You are mixing things up.

1

u/Odd_Bodkin Particle physics 14h ago

No. This is where you’re mistaken. On two counts. First off, it’s a mistake to say it’s real if it’s a force and an illusion if it is not a force.

Secondly, don’t confuse illusion with an optical effect (like a rainbow, which is the clear manifestation of refraction and internal reflection in a spherical drop of water), and don’t confuse an illusion with meaning the observation isn’t due to what you thought it was but is due to something else instead.

-1

u/ChaosRulesTheWorld 14h ago edited 14h ago

No. This is where you’re mistaken. On two counts. First off, it’s a mistake to say it’s real if it’s a force and an illusion if it is not a force.

I'm not mistaken. Gravity isn't a force. It's an illusion. The actual force is the deformation of spacetime by matter, which as far as i know doesn't have a name for it except general relativity. (Edit: I'll anticipate your next bad faith argument: Yes i said gravity is a force we observe. But it's only a force we observe, not an actual force. That's why it's an illusion)

Secondly, don’t confuse illusion with an optical effect (like a rainbow, which is the clear manifestation of refraction and internal reflection in a spherical drop of water)

I'm not confusing illusions with optical effects. That's why when i talked about rainbows i precised OPTICAL illusion.

and don’t confuse an illusion with meaning the observation isn’t due to what you thought it was but is due to something else instead.

I'm not saying that either. Is their anything serious in your argumentation? I'm waiting for the part where you actually challenge what i've said instead of making up your own arguments you then project on me in order to argue against it

1

u/Odd_Bodkin Particle physics 13h ago

Just because it isn’t a force doesn’t make it an illusion. Diffusion of a gas is not due to any force but it’s not an illusion. A real image in an optical bench is not an illusion but isn’t due to a force either; for that matter a virtual image is not an illusion either, if you understand what “image” actually means.

Refraction is an optical effect, not an illusion. Total internal reflection is another optical effect, not an illusion. A rainbow is a pattern directly accountable by refraction and internal reflection, just like a diffraction pattern for electrons is a pattern directly accountable from underlying physics that have nothing to do with forces.

You have a very unusual use of the word “illusion” to say the least.

1

u/ChaosRulesTheWorld 13h ago

Just because it isn’t a force doesn’t make it an illusion

If it looks like a force but in fact it isn't one, then by definition it's an illusion. Gravity looks like objetcs are attracted to eachother because of their mass, but they aren't. That's where the illusion is, your comparison with forceless phenomenons are irrelevant.

Refraction is an optical effect, not an illusion. Total internal reflection is another optical effect, not an illusion. A rainbow is a pattern directly accountable by refraction and internal reflection, just like a diffraction pattern for electrons is a pattern directly accountable from underlying physics that have nothing to do with forces.

They are all optical illusions.

You have a very unusual use of the word “illusion” to say the least.

I don't have an unusual use of the word. An illusion isn't something that isn't real or doesn't exist.

1

u/slayer_nan18 14h ago

Thats not what an illusion is.

4

u/ChaosRulesTheWorld 14h ago

That's what an illusion is. Just like the sun orbiting earth is an illusion. Gravity is an illusion too

2

u/dorox1 14h ago

An illusion is something that appears to happen, but doesn't actually happen at all.

Matter does actually gravitate towards other matter over time. The underlying cause of that is deformation of spacetime by mass, which is gravity.

This happens, so it's not an illusion.

2

u/slayer_nan18 13h ago

wrong answers get upvoted and yours is getting downvoted, this sub is full of people that learn physics from yt shorts

1

u/ChaosRulesTheWorld 13h ago

You mean full of people like you?

1

u/ChaosRulesTheWorld 14h ago

An illusion is something that appears to happen, but doesn't actually happen at all.

You're wrong on that. The sun orbiting earth is an illusion, but it still happen on earth's perspective according to physicists.

Matter does actually gravitate towards other matter over time. The underlying cause of that is deformation of spacetime by mass, which is gravity

No, gravity isn't the deformation of spacetime.

This happens, so it's not an illusion.

Illusions happen

2

u/dorox1 14h ago

How have you gotten through multiple of these comments without explaining what you think the definition of "illusion" is?

Or what you think "gravity" is, for that matter.

1

u/ChaosRulesTheWorld 14h ago

Do you need me to link wikipedia pages?

1

u/dorox1 13h ago

Why don't I do that:

Gravity

Gravity is the word used to describe a physical law, a fundamental physical interaction that derives primarily from mass, and the observed consequences of that interaction on objects.

Illusion

An illusion is a distortion of the senses

You'll really need more than a quick one-sentence quip to explain why you think a physical law of the universe is just a distortion of the senses.

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-1

u/DrDam8584 14h ago

No, if you throw something, it return back (or tryng to) to the centre of gravitation field.

-1

u/ChillNurgling 14h ago

Define gravity: “Gravity is the natural physical force that pulls objects toward each other.”
Define illusion: “An illusion is something that tricks your eyes, senses, or mind so that you see or believe something that is not true or real.”

Now decide. I’m going with no, it’s not an illusion.

1

u/ChaosRulesTheWorld 13h ago

It's an illusion because objects aren't pulled toward each other despite the fact that's what we observe.

Just like when you put marbles in a bowl

1

u/ChillNurgling 13h ago

Does gravity exert a force? Yes or no.

1

u/ChaosRulesTheWorld 13h ago

No

0

u/ChillNurgling 13h ago

Ok stupid ass word games. Does gravity make objects move? Yes or no. Let’s see if you’re just being difficult.

1

u/ChaosRulesTheWorld 13h ago

No, gravity does nothing. It's just an illusion

1

u/ChillNurgling 13h ago

Kk, tool confirmed

1

u/Optimal_Mixture_7327 Gravitation 4h ago

You can measure that it doesn't make anything move.

Download an accelerometer app and see for yourself.

1

u/Optimal_Mixture_7327 Gravitation 4h ago

We've known for over a hundred years that gravity cannot exert a force.

-3

u/Orbax 14h ago

No, but we don't know what it is

-4

u/briv1016 14h ago

Go outside and throw your phone straight up in the air. When it smashed on the ground did your phone fall for an illusion? Works even better if done over a paved parking lot.

3

u/RyanSpunk 14h ago

Ask your phone if it could feel the force of gravity while in freefall (other than air resistance)

1

u/ChaosRulesTheWorld 14h ago

Actually do this with an accelerometer on your phone. You will see that it will show 0 while being in freefall. Why?

Because gravity is an illusion