• m0rph
In summary, the question asks about the force keeping the Earth in orbit around the Sun, and how it does not eventually fall into the Sun due to gravity. The answer is that the Earth has sufficient initial velocity to stay in a stable orbit, similar to a cannonball being shot at a high speed. Therefore, there is no need to invoke Einstein's General Relativity to explain this phenomenon.

#### m0rph

I just joined this forum, so forgive me if this is an inappropriate question for this section.

Also, I have not studied physics to any meaningful degree; I am just a curious person who likes to think about the universe. So, on to my question...

The premise:
I was watching a documentary about Einstein in which the commentary described the force of gravity being a manipulation of space-time. Following this was a graphical representation of the Sun distorting the space-time around it, causing the Earth to orbit around the Sun as if it were a marble spiraling down a funnel-shaped surface.

My Question:
Given that the space-time is warped around the Sun, which is the force (gravity) keeping Earth revolving around it. How is it that the Earth does not eventually get pulled into the Sun rather than stay in its stable, consistent orbit? There seems to be nothing keeping the Earth from stopping at the current distance from the Sun. If gravity is he force that keeps us humans on the ground, and if we were to fall through a hole that goes through the entire
Earth, wouldn't we end up stopping at the center of the Earth? So, if gravity is the same force that is pushing the Earth toward the Sun, it would seem as though the Earth should keep heading toward the Sun until something stops it. I'm guessing this has something to do with how the solar system was originally formed and how it got to its current state. I'm just curious to know what exactly is keeping or stopping the Earth from being drawn further toward the Sun since the Sun's gravitational pull (or space-time distortion) is the only thing keep it in orbit in the first place.

Anyway, sorry about the lengthy post. I just had all these thoughts come rushing to my head when I saw the documentary's description of how space-time gets distorted. :)

There's no need to invoke Einstein's General relativity to answer this question. The answer is initial velocity. We ARE falling towards the Sun in fact. Every second, we accelerate towards the Sun; however, we also have sufficient initial velocity that we are in a stable orbit. It's like if you shot a cannon ball really fast. The faster you shoot the cannonball, the farther it travels before it hits the Earth. If you shoot the cannonball fast enough, it will drop towards the Earth at the same rate that the Earth is curving, so it never hits the surface.

Here's an illustration:

Matterwave said:
There's no need to invoke Einstein's General relativity to answer this question. The answer is initial velocity. We ARE falling towards the Sun in fact. Every second, we accelerate towards the Sun; however, we also have sufficient initial velocity that we are in a stable orbit. It's like if you shot a cannon ball really fast. The faster you shoot the cannonball, the farther it travels before it hits the Earth. If you shoot the cannonball fast enough, it will drop towards the Earth at the same rate that the Earth is curving, so it never hits the surface.

Here's an illustration:

Thanks Matterwave. I actually thought of a similar solution this morning and this makes perfect sense. I really appreciate the response!

## 1. What is space-time?

Space-time is a concept that combines the three dimensions of space (length, width, and height) with the dimension of time. It is a mathematical model that is used to describe the physical universe and how it operates.

## 2. How does space-time affect gravity?

According to Einstein's theory of general relativity, space-time is curved by the presence of massive objects such as planets and stars. This curvature of space-time is what we experience as gravity.

## 3. Can space-time be altered?

Yes, space-time can be altered by the presence of massive objects or by high speeds. This is known as the theory of relativity, which states that space and time are not absolute, but are relative to the observer's frame of reference.

## 4. What is the difference between space-time and spacetime?

Space-time and spacetime are both used to refer to the same concept, the combination of space and time. The term "space-time" is more commonly used in physics, while "spacetime" is often used in science fiction or popular culture.

## 5. How is space-time related to the Big Bang theory?

The Big Bang theory states that the universe began as a singularity, an infinitely small and dense point. As the universe expanded, space and time were created, leading to the formation of the universe we know today. Therefore, space-time is an integral part of the Big Bang theory and our understanding of the origin of the universe.