Einstein and Newton and gravity

[Ahmed Samra]

According to GR gravity is not a force so what is gravity according to GR? And according to Newton gravity is a force. Who's right and why?

 

[Crazymechanic]

hi there , this question has been up here many times , I'm sure doing a search in this forums history or google will reveal a lot of what you asked but to put it out for you

According to GR gravity is spacetime curvature , as to who is right and who is wrong well they both are right and they both are wrong , it depends on what scales and situations you look.
If you are concerned with everyday objects here on Earth Newton gravity is perfectly fine , if you want to understand and calculate the gravitational pulls exerted in space by massive objects like stars and big planets you take GR also GR is helpful in many other aspects , GR just goes deeper than Newton could in his time with his understanding , it takes on phenomenon like redshift and that mass can bend space just as much as energy can and so on.

Have you took a look on
http://en.wikipedia.org/wiki/General_relativity ??

 

[Nugatory]

According to GR gravity is not a force so what is gravity according to GR? And according to Newton gravity is a force. Who's right and why?

They're both right.

In the mathematical formalism of Newton's theory, gravity is represented as a force and its effects are described by the equation F=ma. In the mathematical formalism of GR, gravity is just objects moving in a straight line at a constant velocity as you'd expect them to do when there's no external force acting on them.

The predictions of the two theories are experimentally indistinguishable under a very wide range of conditions. They make different predictions across cosmological distances and under extreme gravitational conditions, and in those cases experiments generally support the GR prediction. Neither works when the masses involved are large and the distance and time scales are very small.

That makes them both right in their respective domains of applicability and only there, like any theory.

 

[Dale]

According to GR gravity is not a force so what is gravity according to GR? And according to Newton gravity is a force. Who's right and why?

This is not the difference between GR and Newtonian gravity. Because the force is proportional to mass Newtonian gravity can also be geometrized, this is called Newton Cartan gravity.

 

[sardar]

Both Einstein and Newton are considered to be brilliant scientists who have made significant contributions to our understanding of gravity. However, their explanations of gravity differ in some fundamental ways.

According to Einstein's theory of General Relativity (GR), gravity is not a force. Instead, it is the curvature of space-time caused by the presence of mass and energy. In other words, massive objects, such as planets and stars, create a "dip" in the fabric of space-time, and other objects with less mass are pulled towards this dip. This is often visualized as a bowling ball on a trampoline, with smaller objects like marbles rolling towards it. In GR, gravity is not a force acting between objects, but rather a consequence of the curvature of space-time.

On the other hand, Newton's theory of gravity states that it is a force that acts between objects with mass. According to Newton's law of universal gravitation, any two objects in the universe are attracted to each other with a force that is directly proportional to their masses and inversely proportional to the square of the distance between them.

So, who is right? Both theories have been extensively tested and have been shown to accurately predict the behavior of gravity in different scenarios. However, Einstein's theory of GR has been able to explain certain phenomena, such as the bending of light around massive objects, that Newton's theory cannot. Additionally, GR has been able to successfully predict the existence of black holes, which were later confirmed by observations.

In summary, both Einstein and Newton have contributed valuable insights into our understanding of gravity. While Newton's theory of gravity is still widely used for most practical purposes, Einstein's theory of GR provides a more comprehensive and accurate explanation of gravity. Therefore, it can be said that both scientists were right in their own ways, but Einstein's theory has provided a more complete understanding of gravity.