# Subatomic particle and space curvature

• richerrich
In summary, the conversation discusses the relationship between subatomic particles, spacetime curvature, and gravity. It is concluded that each individual particle does affect spacetime, but the overall effect is that of a macroscopic object. The need for a graviton is also discussed, with the possibility that a quantum theory of gravity may use gravitons. It is also mentioned that massive bodies emit gravitons to tell spacetime how to curve through the stress-energy tensor. The potential impact of removing gravitons and the existence of gravitons for all subatomic particles are also briefly mentioned.
richerrich
Can we say that each subatomic particle affects space time such that collectively as big as a planet it explains why there is gravity?

Thank you very much.

Well, to the big question you're asking the answer obviously has to be yes. Each individual particle does curve spacetime according to general relativity, having its own "gravitational field", and we know the net effect is that of a macroscopic object. You have to be careful in thinking about how you would actually do such a computation. The field equations of GR are not linear (in contrast to, say, the field equations for electromagnetism), so you cannot simply "add" the spacetime curvatures from all the different elementary particles and recover what we know to be the curvature for an object like the earth. Instead, you have to actually consider the system of 10^50 or however many particles you want in the stress energy tensor and then proceed to solve the einstein equations (a tall task indeed!).

But schematically, yes what you're saying is correct, just note that gravity is not an emergent phenomenon but does exist on the smaller scales as well.

Nabeshin said:
Well, to the big question you're asking the answer obviously has to be yes. Each individual particle does curve spacetime according to general relativity, having its own "gravitational field", and we know the net effect is that of a macroscopic object. You have to be careful in thinking about how you would actually do such a computation. The field equations of GR are not linear (in contrast to, say, the field equations for electromagnetism), so you cannot simply "add" the spacetime curvatures from all the different elementary particles and recover what we know to be the curvature for an object like the earth. Instead, you have to actually consider the system of 10^50 or however many particles you want in the stress energy tensor and then proceed to solve the einstein equations (a tall task indeed!).

But schematically, yes what you're saying is correct, just note that gravity is not an emergent phenomenon but does exist on the smaller scales as well.

Then why is there a need for graviton?

richerrich said:
Then why is there a need for graviton?

It is though that quantum theory applies to everything, but we do not have a quantum theory of gravity. A quantum theory of gravity probably will use gravitons.

George Jones said:
It is though that quantum theory applies to everything, but we do not have a quantum theory of gravity. A quantum theory of gravity probably will use gravitons.

So graviton should exist because Einstein can't explain Quantum Mechanics?

richerrich said:
So graviton should exist because Einstein can't explain Quantum Mechanics?

I woudn't put it this way.

richerrich said:
So graviton should exist because Einstein can't explain Quantum Mechanics?

I may have missed something. How can we then reconcile gravitons and spacetime curvature to be one principle that explains gravity?

Massive bodies emit gravitons to tell spacetime how to curve through the stress-energy tensor.

Kevin_Axion said:
Massive bodies emit gravitons to tell spacetime how to curve through the stress-energy tensor.

If you remove graviton will spacetime be still curved one way or another (or perhaps its curvature will be in a flux)? Does this mean that all subatomic particles have its own graviton?

Hypothetically, right now Einstein's General Theory of Relativity states that mass and energy tell the stress-energy tensor how to curve spacetime, the graviton just appears logical because all other forces have bosonic carriers.

Kevin_Axion said:
Hypothetically, right now Einstein's General Theory of Relativity states that mass and energy tell the stress-energy tensor how to curve spacetime, the graviton just appears logical because all other forces have bosonic carriers.

Thanks! That does clarify things for me.

## 1. What are subatomic particles?

Subatomic particles are tiny particles that make up atoms. They include protons, neutrons, and electrons, which are the building blocks of matter. There are also other subatomic particles, such as quarks and leptons, that are important in understanding the structure of matter.

## 2. How are subatomic particles related to space curvature?

According to the theory of general relativity, mass and energy can cause a curvature in the fabric of space-time. As subatomic particles have mass and energy, they can contribute to this curvature. This means that the presence of subatomic particles can affect the way objects move through space and time.

## 3. What is the role of subatomic particles in understanding the universe?

Subatomic particles play a crucial role in understanding the universe. They are the building blocks of matter and can help us understand how particles interact and form larger structures, such as atoms and molecules. Studying subatomic particles can also provide insights into the fundamental forces that govern the universe.

## 4. How do scientists study subatomic particles?

Scientists study subatomic particles using high-energy particle accelerators and detectors. These tools allow them to create and observe subatomic particles in controlled environments. They also use theoretical models and mathematical equations to make predictions and understand the behavior of subatomic particles.

## 5. Can subatomic particles be used in practical applications?

Yes, subatomic particles have many practical applications. For example, they are used in medical imaging techniques, such as PET scans, and in nuclear power plants to generate energy. Scientists are also studying how to use subatomic particles in advanced technologies, such as quantum computing.

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