Cosmology / Astrophysics

[KeinesV]

Is anybody here all that versed in cosmology or astrophysics? I have a few questions related to a scenario for a longtime WIP, that I would like to set straight if I may.

[Sammi]

I took a class and have a textbook. I certainly may be able to help, if only to find what you need.

[KeinesV]

How advanced is the text book? :P I have a scenario that I'm worried about the plausibility of because I only have a layman's understanding of the vagaries of gravity. Since gravity is a quantifiable force, I expect that with tweaking the math can work... but I'm not quite familiar enough with the necessary math. I was hoping to bank on the odd chance that someone here was a fully grown astrophysics nerdtaku, as opposed to myself, who is only in astrophysics nerdtaku infancy.

[Sammi]

It's not very advanced. On the subject of gravity, it only goes so far as to discuss how gravity bends space and time and how black holes function.

I don't know how much help I can be, but now I'm wondering what your scenario is. Are you willing to indulge some curiosity?

[Thuriel]

This is completely unhelpful, but I came into this thread thinking it was about astrology and horoscopes and stuff. I really need to learn how to read titles. *cough*

[mcnicks]

I have a Physics degree... technically... that was some time ago, though.

[KeinesV]

Well then I'll work on articulating my questions, and toss them at you. Physics is half of astrophysics. Ultimately I want to get a doctorate in the theoretical variety.

[MichaelB]

What exactly are your questions? There's very little that some patient Google-searching won't uncover. I'm looking at a site right now that postulates that the speed of gravity is many orders of magnitude faster than the speed of light: "The Speed of Gravity - What the Experiments Say discusses all the experimental evidence that bears on the intriguing question of the speed of gravity, concluding that it must be many orders of magnitude faster than light in forward time (i.e., no causality violations)."

A Reputable (Presumably Peer-Reviewed) Cosmology/Gravity/Quantum Physics Research Papers (http://www.metaresearch.org/cosmology/cosmology.asp) Website

[KeinesV]

What did you think I meant when I said I would articulate my questions? Patience michael, when I can ask them elloquently, I will.

[Sammi]

What exactly are your questions? There's very little that some patient Google-searching won't uncover. I'm looking at a site right now that postulates that the speed of gravity is many orders of magnitude faster than the speed of light: "The Speed of Gravity - What the Experiments Say discusses all the experimental evidence that bears on the intriguing question of the speed of gravity, concluding that it must be many orders of magnitude faster than light in forward time (i.e., no causality violations)."

A Reputable (Presumably Peer-Reviewed) Cosmology/Gravity/Quantum Physics Research Papers (http://www.metaresearch.org/cosmology/cosmology.asp) Website
I don't see why gravity needs a speed. I mean, as far as I can tell, gravity is just the action of massive bodies on the curvature of space-time, like a big weight set on a trampoline. Similarly, if space-time is one big thing, or field, like a trampoline, it would have no speed. Once bent, the space-time stays bent unless the mass goes away, and light entering the space of, say, a black hole, can't escape the excessive bentness of space-time.

[mcnicks]

Talking about the 'speed' of something like gravity is a bit misleading because, when we talk about speed, what we tend to mean is the speed of the transmission of information through a medium. That is what fascinates us about the idea of anything travelling faster than the speed of light. In classical terms, the action of gravity at a distance may appear to happen faster than the speed of light in vacuum, but no meaningful information would be transmitted in the process.

Btw, that Meta Research site is a non-profit private organisation. The articles do not appear to be peer reviewed. It actually sounds like the vehicle of a single person, Tom Van Flandern:

"The Meta Research Bulletin (MRB) is published four times a year, about mid-month in March, June, September, and December. The publisher is Meta Research, Inc. The editor and author of all articles not otherwise credited is astronomer Tom Van Flandern. Articles may be popular, semi-technical, or technical in style; but writing for the broadest possible readership is strongly encouraged. Permission to reprint articles will usually be given upon request as long as the source is credited."

[MichaelB]

Hmm, looks like I missed that bit. Pretty popular site, though. Numbr one in the Google search for 'Cosmology'.