I want to help but I didnt understand your questionjohn-of-the-divine said:
Theres no substance in empty space.Theres no aether.john-of-the-divine said:
john-of-the-divine said:
Where ? Any source ?john-of-the-divine said:
Its not inconclusive..Its a fact of nature..Light doesn't need a medium to travel.john-of-the-divine said:
"Spacetime tells matter how to move; matter tells spacetime how to curve"(John Archibald Wheeler)john-of-the-divine said:
Pushing pulling is strange words to describe the situation I guess.I would say matters attract each otherjohn-of-the-divine said:
john-of-the-divine said:
What is "known" so far is what has been observed: light has no problem traversing the entire width of the visible universe. So there is good reason to believe it travels forever.john-of-the-divine said:
By observing how light behaves.
The idea that space can be empty and yet have a geometry (and other properties) may be difficult to wrap your mind around, but it is well supported by observations.john-of-the-divine said:
Because GR predicted that predicted very massive objects would act as a gravitational lens,john-of-the-divine said:
The general answer to the question of "what is...?" anything, is that the thing you want to know about "is" the sum of its known and theorized properties. This is likely to be unsatisfying to you because the known/theorized properties of space are probably less than you want to believe it has.john-of-the-divine said:
By observing how light behaves in it.
That isn't a very good approach to learning.
I'm not sure what you mean, but ok...john-of-the-divine said:
Yes; astronomy. We learn a lot about space by observing light that has traveled across the universe.
Clearly. But the math describes very well what is observed.
You're welcome, but don't give up on learning just because you didn't go to school for it. It's true that you won't be able to learn it to the same depth as a college degree, but there is some good learning you can do.
What did who mean? OP = "Original Post" (your first post in this thread) or "Original Poster" (you) in most cases on a discussion forum.john-of-the-divine said:
Ah, okay. I just now used my Mentor superpowers to read his previous version, and he was just saying that it sounded like you hadn't heard of several very accurate experiments that have been done in pretty different ways to verify the speed of light and no aether. Have you read the Wikipedia pages about the speed of light and various experiments done to verify that c is constant in a vacuum and not dependent on moving through some medium?john-of-the-divine said:
It would be difficult for the math to be more than a little wrong because we use it to do practical things like navigate with Google maps and it works.john-of-the-divine said:
It's usually fine for well-understood stuff (which this is). For cutting edge theories, it can be a bit problematic (with lots of folks editing the articles). Give it a try and tell us what you think...john-of-the-divine said:
from here to the moon isn't very far when you consider the vastness of space. idk, I'm checking out the link that berkeman sent meruss_watters said:
I'm not sure what that comment is in reference to, but our observations impacting Relativity span the entire observable universe.john-of-the-divine said:
The post that @bahamagreen edited used to have reference to the experiments using the retroreflectors on the moon.russ_watters said:
I'm saying that compared to the size of the universe, the distance to the moon is like an inch compared to 100 miles. I don't know the actual scale, but I'm saying we can't know the true effects on light until we can go a light year away, shoot a laser back to earth, and study that light.russ_watters said:
We've basically done that. We can look at the light from certain light sources (different kinds of stars and related bodies) at very different distances and compare them. What do you think the main difference is in the light coming from a nearby star and one a few billion light years (LY) away?john-of-the-divine said:
It may not give quite the same information, but studying light that has traversed much of or all of the universe is plenty helpful.john-of-the-divine said:
ah, but all that is based on the belief that in space, the light takes x amount of time to travel x amount of miles, when we really don't know what the "fabric" of space time is made out of? I don't know, maybe I'm thinking too high for my tiny mindberkeman said:We've basically done that. We can look at the light from certain light sources (different kinds of stars and related bodies) at very different distances and compare them. What do you think the main difference is in the light coming from a nearby star and one a few billion light years (LY) away?
If you're really asking what the "fabric" of spacetime is, I think I'll move this thread to the Relativity forum, where you can get more knowledgeable replies. I'll mark it with a "B" prefix to let others know that you'd like responses on a Basic level.john-of-the-divine said:
lol. thanks guys.berkeman said:If you're really asking what the "fabric" of spacetime is, I think I'll move this thread to the Relativity forum, where you can get more knowledgeable replies. I'll mark it with a "B" prefix to let others know that you'd like responses on a Basic level.
No they don't.john-of-the-divine said:
hence the reason why I said "or so it seems"rootone said:
There is no fabric in GR. That is a very misleading pop-sci trope and is utterly useless for actually doing GR.john-of-the-divine said:
There's some serious good news here: Thanks to the internet you don't have to go to a ridiculously expensive top-flight school to learn this stuff. Textbooks and lecturers' notes from very strong academic programs are available online; for example, Sean Carroll and Gerard t'Hooft have both placed first-rate general relativity textbooks on the web, and there are many more good online resources.john-of-the-divine said:
Yes, tautologically. X really is just X for any X.john-of-the-divine said:
The Michelson Morley experiment ruled out a rigid aether and ring interferometer experiments ruled out a dragged aether. The only aether that remains compatible with experiments is experimentally indistinguishable from no aether.john-of-the-divine said:
