# If Mass Curves Spacetime, How Does It Uncurve Again?

Part 1

### Newton’s Law of Gravitation

For hundreds of years prior to Einstein, our best Gravitational Theory came from Sir Isaac Newton.

Newton’s concept of the Universe was simple, straight-forward and philosophically dissatisfying to many.

He claimed that any two masses in the Universe, no matter where they were located or how far apart they were, would instantaneously attract each other via a mutual force known as Gravity.

He claimed a certain absolution.

The more massive each mass was, the greater the force, and farther away they were (squared), lesser the force.

This would apply to all objects in the Universe and Newton’s Law of Universal Gravitation, unlike all the other alternatives put forth, agreed with observations precisely.

Gravity and mass are directly proportional to each other. They complement each other.

Where there is mass, there is gravity. Where there is gravity, there has to be some mass.

We are taught that mass warps Spacetime, and the curvature of Spacetime around mass explains the gravity .

So an object around the Earth, for example, is actually traveling in a straight line through curved spacetime.

That makes sense.

But when a mass (like the Earth) moves through Spacetime and bends it, what makes it not stay that way?

What mechanism unwarps that area of Spacetime as the mass moves on?

And more importantly (for now), was Newton right about Spacetime being absolute?

Part 2 Newton Was Wrong About Spacetime Being Absolute

Categories: science

### 14 replies ›

1. Would it take a second mass to unbend what the Earth has done? But then there would need to masses close by, relatively speaking, or else space-time is bent all over the cosmos. Maybe it is. Maybe the idea of another Earth on the other side of the sun gains traction.

Like

2. As we know if there’s mass it’ll bend space-time curvature but if there isn’t any mass so it won’t bend. You can take example as ; Consider a trampoline and put a 10kg block at centre of it, what will happen?? It’ll bend trampoline, and what if you remove it back? Trampoline will get back to normal. And what if you slide that weight around the trampoline? It’ll simple bend trampoline where it goes and the previous bend will restore because there’s no mass there. Same phenomenon is applied here. There’s no different mechanisms to unfold it. It happens because there isn’t any mass left to bend the space time curvature.

Like

• You seem to be new here.
The questions I ask are rhetorical.
I actually have a PhD in Theoretical Physics and in Mathematics.
It’d be safe to assume that I know the answer.
Don’t really need Trampoline examples and especially, don’t need naive explanations.

Like

• Forgive me if you took me wrong,but I simply added my answer to your questions.. not all readers are holding PhD so if I have to explain in simple terms then I have to take example like that.. that’s why I explained it. Thank you 😊

Like

• As you might have been able to read, it’s part 1 of the series.
So by the time I reach the end, you might ptobably understand it.

Like

3. Don’t feel too bad about not understanding General Relativity. It is a system of partial differential equations that describe how massive objects distort both space and time in their vicinity, causing effects not seen in Newtonian physics such as the deflection of light near massive objects. What happens is the object distorts space and time such that an object moving near it with a certain momentum is forced to follow a curved path. The curve will change depending on how fast the object is traveling. Spacetime has a certain tension to it, which is why things like gravity waves have been detected, and bounces back when the object is no longer in the same area. It’s complicated, but has a beauty and simplicity to it if you understand the advanced mathematics.

Like

• I have a PhD in both, Mathematics and Theoretical Physics.
I guess one can assume that I might understand General Relativity, given that my fopic for my first thesis was String Theory.

Like

• Well sorry if you took my comment wrong, but it just seemed odd that you would think spacetime could be permanently bent out of shape. You might as well ask what makes a spring return to its original shape once force is removed from it.

Like

• Well, as it says, it is the first part.
And when I explain physics, I assume not everyone has a PhD in the subject like me.

Like

• And if you would have read any of previous posts I published, you wouldn’t have felt the need to educate a theoretical physicist on the topic of General Relativity.

Like