How does matter accelerate in a gravitational field

[49ers2013Champ]

Naty, WN, others:

I guess what I'm struggling with here is that I thought there had to be relative motion for time to be present. I've already emailed Mr. Donis about this, and while he struck it all down, I'm still missing something. I completely understand that the mathematics suggests that the point is perhaps stationary on the space (spatial?) side of the graph but is advancing through, or perhaps curving, the time side of the graph--and this is all based off the particle or mass in deep, deep space and far away from the influence of gravity. I thought all notions of time were based off relative motion--our orbiting the sun being the most obvious example. Another example, perhaps a silly one, is this: Albert, Isaac, and Peter are all far removed from each other in deep, deep space, but in the same universe. They all have rocket boosters. They all hit them and eventually cross paths, and they start hanging out. They've never heard of the concept of time, aging, etc. But now, since they are seeing each other moving around and talking to each other, they start to record these events in their minds--a memory develops--and they begin to experience the notion of time. "Yesterday", Albert's mustache was long; today it's trimmed. You get my point.

I'm sure I'm completely wrong, but I just don't know how a material point (mass, particle, or body) can be said to be curving spaceTIME. To me, time seems to be a human-constructed concept that can be applied to science only under the right conditions--planets orbiting stars and other types of relative motion.

Everyone, thanks for your thoughts. In no way am I saying I'm right--please don't misunderstand me. I'm simply trying to communicate that the time part of spacetime curvature in the aforementioned scenario doesn't make sense to me.

 

[Drakkith]

Why would relative motion be required for time? Let's say your particle in this otherwise empty universe is a muon, an elementary particle similar to an electron. It has a half life of 2.2 microseconds. There is no reason that I know of to believe that it wouldn't decay just because there is no relative motion. Besides, a muon in the real world has no way of telling time. It can't see a clock or watch as planets orbit stars, yet it still obeys time.

 

[Naty1]

49er's...

I guess what I'm struggling with here is that I thought there had to be relative motion for time to be present.

Keep an eye out for any source that claims that. See what the 'logic' might be. It's just not mainstream science.

What we know, so far, for example is that relative motion affects the relative passage of time and that differences in gravitational potential also do. Maybe there is something else we haven't discovered yet. [We rarely know all we don't know.]

No one knows before the big bang if time existed or not. Maybe everything emanated from that source, but how did anything get started if there was no time? What would that even mean?

... I just don't know how a material point (mass, particle, or body) can be said to be curving spaceTIME. To me, time seems to be a human-constructed concept that can be applied to science only under the right conditions--planets orbiting stars and other types of relative motion.

It took an 'Einstein' to figure that out, so don't feel bad...it IS rather crazy! [Did you read the first quote in my signature below??] For thousands of years nobody knew how any forces could act at a distance. Even Newton did not know. Then we created field theories, like electromagnetic and gravitational, and voila we had a means of studying and predicting physical phenomena. The 'right conditions' you mention for gravity...that is, spacetime curvature...so far seems to be everywhere except black hole singularities and the big bang itself. Quantum mechanics is not applicable at these two extremes. But not bad for a start!