Why do objects rest on space thus causing gravity?

[nitsuj]

Well, no offense, but that doesn't make any sense. You need the notion of time to make sense of the words "rapidly", "slowly" and "move". So it doesn't make any sense to define time in terms of those words. I mean, it's circular to do so.

Yay philosophy!

 

[Soundmike]

I've heard it explained is that we are all falling.. everything, we fall to the earth, the Earth is falling towards the sun, the sun is falling towards the galactic centre...
to understand gravity maybe this would be helpful



and to get an idea of angular momentum counterbalancing

gravitational pull maybe this would be helpful



And to get an idea that space itself is flowing listen to what said about it when it reached a black hole



I don't get people on here making comments like "I'd need a mathematical equation to explain it" BS!
The cracker of a concept could be a beggar off the street who has the clarity to see blind to the nuts and bolts...
My favourite phrase.. explain it to me like I'm an 8 year old... but saying that if anyone wants to share mathematical equations with me on here it would be my please andn honour to learn your perspective

 

[Drakkith]

I don't get people on here making comments like "I'd need a mathematical equation to explain it" BS!

Typically the mathematical model used is very, very specific and rigorous, and understanding the math usually means you understand the theory without needing someone to 'translate' it into common language. In addition, many concepts are explained very well when you understand the math, but trying to explain the same concept without the math is extremely difficult and prone to confusion and misunderstanding.

For example, explaining the expansion of space is very hard to do if you leave out all the math. You need to bring in analogies like bread rising, balloons stretching, and others that give people the wrong ideas. If, instead, you focus on the math describing how galaxies move apart over time, it is immediately clear just what expansion means. No analogies needed. No misunderstandings.

A big part of the problem is that normal, everyday language is highly subjective. Many words mean slightly different things to different people (or sometimes even wildly different things). For example, if I told you, "I ran to the store earlier", what would that mean to you? Did I get in my truck and drive there? Did I literally run to the store using my own two feet? Did I call a cab or a friend for a ride? These questions could go on and on.

If I gave you a mathematical formula describing my position over time with respect to the store, there's little-to-no confusion there. And from that formula you could get several other properties, such as velocity and acceleration. Now, while this doesn't tell you everything that happened, such as which drinks I purchased or how I got there, it is very, very specific and accurate to what it does tell you.

An example specific to this thread is the description of gravity as one object falling towards another. If I'm falling towards something, that, to me, means that I'm approaching that object. For example, falling to the ground means my I'm moving towards the ground. But look at the Earth's orbit. Being an ellipse, this orbit requires as to be moving away from the Sun for half of the orbit. How can gravity be us falling towards an object if the distance between us and that object is increasing? Now, I'm sure you could write several paragraphs explaining exactly what falling means in this context so that you come up with a way to say that gravity is one object falling towards another. Or, you could forego everyday language altogether and use a math-based model which is much more exact in its language and makes numerical predictions that can be verified to great precision. I think I prefer the latter.

 

[Amrator]

I've heard it explained is that we are all falling.. everything, we fall to the earth, the Earth is falling towards the sun, the sun is falling towards the galactic centre...
to understand gravity maybe this would be helpful



and to get an idea of angular momentum counterbalancing

gravitational pull maybe this would be helpful



And to get an idea that space itself is flowing listen to what said about it when it reached a black hole



I don't get people on here making comments like "I'd need a mathematical equation to explain it" BS!
The cracker of a concept could be a beggar off the street who has the clarity to see blind to the nuts and bolts...
My favourite phrase.. explain it to me like I'm an 8 year old... but saying that if anyone wants to share mathematical equations with me on here it would be my please andn honour to learn your perspective

*Sigh* Where's Feynman when you need him?
If I could explain it to the average person, I wouldn't have been worth the Nobel Prize. - Richard Feynman

 

[Nugatory]

or all your implied mathematical understanding which I take for granted is extensive that you and others who have written here are unable to or unwilling to use the very words which helped you to learn these tools...

I'm having some trouble seeing the validity of this criticism. Further up in this thread we have this post which contains pointers to some of the best plain-English explanations that you'll find anywhere. You don't have to move past those videos to the rigorous mathematical formalism of general relativity if you don't want to, and you'll still have a perfectly sound understanding of how general relativity works.

Of course understanding how general relativity works is not the same thing as understanding general relativity at a level that allows you to solve problems in GR ("How do we expect the orbit of a planet to differ from the Newtonian prediction, and for which objects in the solar system will that difference be large enough to measure?") or to come up with new ideas about what GR means - for that, there is no substitute for working through the math.

 

[Nugatory]

I'm closing this thread, as the issues that are raised in the most recent posts (including my own reply) are best discussed in a new thread - we've answered the original poster's question in this thread several times over.