The joint is jumpin' around a black hole--new sim

[ehkzu]

A Hopkins U. researcher did a computer sim of how matters infalls around a black hole and found huge turbulence. Check out this link: <br />http://www.jhu.edu/news_info/news/home05/mar05/blckhole.html

 

[CalliArcale]

Wow! That is impressive. I like the image of a cosmic "governor" controlling the maximum speed of a rotating black hole. It makes sense, but I never would've thought of it. A lot of this is still over my head (I'm no physics geek) but I understand enough to know it's very cool. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[ehkzu]

Well, sure. No sim can actually duplicate all the factors that impinge on a real world event. And so sims can be wrong-isimo, and should always be considered with these major caveats. And that may be extra true when chaos math is involved, as I think it is here.<br /><br />But then what? Are you saying people shouldn't do sims? Or, more reasonably, that we should take them with a grain of salt? I never said otherwise.<br /><br />Decades ago I read a book called Man's Presumptuous Brain, whose intro said (I'm paraphrasing): "I'm going to make a raft of scientific conjectures in this book. I will state them all bluntly, without the following qualification--that this is a hypothesis, and should be considered tentative until confirmed by rigorous scientific testing. Now, as you read the book, please mentally insert this caveat after everything I assert. That way I can make the book half as long as it would be otherwise. And, better yet, it will be readable." <br /><br />I'm working on the assumption that the space.com community does likewise as they read the various propositions, unless clearly proven otherwise. I do skip the UFO threads, which may involve more credulous folk. But I trust the general scientific smarts of everyone else.

 

[CalliArcale]

And I think we all appreciate that high regard. I will do my best to live up to it!<br /><br />It is of course correct that a computer model is only that -- a model. A simpler example of the limitations of models is the modeling & simulation work that my own company is doing to test a certain product we're developing. Now, you have to do some testing before you can do complete end-to-end live testing; otherwise you'll have a ridiculously unmanageable number of bugs to cope with when you get to that point, and odds are very good you won't even be able to pin most of them down simply because there are so gosh darned many of them. So instead of using actual hardware, we hook our controller units up to a computer which simulates the hardware. That way we can test the software that processes data and issues the relevant commands.<br /><br />That doesn't mean it'll work when we finally get out into the field for end-to-end testing. I'd be shocked if there were no bugs. But there will be far fewer of them. You'll have worked out a lot of your initialization problems (which are less trivial than you might think), validated the basic logic, gotten a handle on your procedures, and detected a lot of data management and buffering issues. So when you do get to end-to-end testing, you only need to do the expensive testing with live equipment for a few weeks rather than a few months. The simulation was enormously valuable, even if it was not capable of simulating reality with absolute perfection.<br /><br />You do want your simulation to be as high-fidelity as is practical, whether you are working in engineering or pure research. The more simplified it is, the fewer quirks will show up.<br /><br />When it comes to this sort fo pure research, a computer model is essentially just a collection of mathematical formulas which are ordinarily far too time-consuming to solve for a useful set of values. If it would take a century to do all of the calculations, it's not going to hap <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Saiph]

simulations are a valid tool steve, and you seem to disregard that fact. They are also just that, a tool.<br /><br />We use them to figure out very complicated systems, to give us a starting point on how to understand some phenomena, or in this case, what to look for.<br /><br />This simulation says that BH accretion should be far more turbulent than we previously thought. It also stresses that the consequences of this turbulance should be observable.<br /><br />So now we check it against current observations...highly variable and intense fluctuations in a BH's output. Okay, seems to fit the bill so far.<br /><br />Then we take a closer look, looking for tell tale signs of turbulence (as sugested by the simulation).<br /><br />Think of it as a computers best guess, after mulling over far, far more details than we can in any reasonable amount of time.<br /><br />Direct observational science cannot be the only approach. Hopefully you'll see that someday. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[5stone10]

<font color="yellow">A computer simulation, regardless of who does it or how, is nothing more than an hypotheses which needs to be confirmed.</font><br /><br /><br />That, and there are only two certanties in life - Death and Taxes !!<br /><img src="/images/icons/rolleyes.gif" />