Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
×

Comment Re:thanks for that great information (Score 1) 191

The only assumption made is that of standard semantics of the use of a qualitative term to indicate a quantity in an imprecise or relative manner. In the case of your post, "fragile" stands for "fragile relative to the average expectation of a population relevant to the context of this subject or discussion". Of course, the assumption of standard language semantics presupposes a more basic one: that one's interlocutor is an entity to which assignment of semantic understanding is apropos; I must admit, though, the possibility that in this assumption I have erred, and you're but a chatbot.

Comment Pretty bad example of a radical change. (Score 0) 191

I know this is Slashdot, but even here the level of stereotyping and hateful crowd mentality exhibited by your post is an eyesore. So let me take this occasion to mirror your posting style by reminding you that, if you perhaps on occasion ventured out from your parents' basement, you might find that there's little basis to your intimation of a statistically significant correlation between involvement in the financial industry and being a "mean, ornery son of a bitch".

Comment thanks for that great information (Score 2) 191

BS. The nervous system is an electrochemical system, not an electrical one; and, while it is physically fragile, it is not nearly as electrically fragile as you suggest, exactly because it is electrochemical rather than electrical in nature. This is a significant reason why 90% of lightning strike victims survive (the skin's lower resistance being another), and why execution through electrocution is nowhere close to being an instant process.

Comment LEDs have better spectrum than CFL, but still crap (Score 0) 182

Even high CRI (color rendering index) LED lighting has a nasty spike in the blue region. See: http://www.ecse.rpi.edu/~schub... This is very different than the smooth blackbody spectrum of solar radiation, though not nearly as bad as the many narrow spikes of a CFL bulb. Color reproduction still suffers, even if not as much as in the case of fluorescents. Compare to a high-end incandescent bulb (such as used in museums and galleries, and in my house), which use filtering reflectors to match daylight spectrum very closely. You can only do this with the smooth spectra of blackbody radiators (such as incandescents) because we lack sufficiently specific (narrow band) filters to deal with the spikes in LEDs, fluorescents, and HIDs, at least without going to extreme expense. So for those of us to whom it matters that artificial lighting should strive to reproduce natural lighting reasonably well, incandescents remain a necessity. At the same time, I do realize that to others efficiency matters, and that is becoming an increasingly significant factor, especially through the actions of the anti-nuclear power lobby.

Comment Mod parent down--talking about wrong paper (Score 1) 356

You're discussing a paper by Rovelli and Vidotto, whereas this discussion is about an unrelated paper by Mersini-Houghton and Pfeiffer. They're unrelated because in the latter an event horizon never forms. Moreover, the Rovelli and Vidotto paper is garbage--see http://backreaction.blogspot.c...

Comment Re:That's not what she's saying (Score 1) 356

Nothing new under the sun. Look up the old term for a black holes resulting from stellar collapse, "frozen star" (after all, to an outside observer, the collapse takes an infinite time to reach the formation of an event horizon due to time dilation--and according to this paper, even that doesn't happen).

Comment Re:But do we see them? (Score 1) 356

Black holes are observationally indistinguishable from dark grey ones. There's no conflict between astronomical evidence on the one hand, and the paper and its thesis of non-formation on the other (a thesis that is part of a decades-old lineage of arguments, going back to the fact that an event horizon takes infinite time to form from the viewpoint of an outside observer).

Comment Mod parent down (Score 1) 356

Because a black hole is understood as something with an event horizon. You don't get to define astrophysical terms; they mean what they're understood to mean by those versed in the art. My suggestion is that we go back to the old and just-as-relevant-today term "frozen star", but I'm not arrogant enough to push for it in the way you want to redefine terms just because you will it.

Comment Re:Black holes can exist without a singularity (Score 1) 356

Mod parent down. He claims he hasn't read the paper, and then takes a guess anyway and not only completely misses, but also presents something absolutely wrong. I can only conclude he got modded up because he posted something appearing vaguely scientific and maybe-perhaps-kind-of-cool-sounding. The facts: Hawking radiation cannot prevent formation of a singularity once an event horizon has formed. Parent poster's appeal to time dilation is a red herring: ultimately this is a matter of geometry--if you start from a configuration that has no event horizon and then one forms, then inside the new event horizon, the geometry of space-time is such that a singularity is a requisite component. Note that the paper itself makes none of the crackpot claims that the parent poster does--it argues that an event horizon doesn't form in the first place because Hawking radiation dissipates the mass of the collapsing star sufficiently to prevent a horizon. And that is eminently plausible, unlike the outlandish proposition in the post I'm responding to.

Comment Re:Black holes can exist without a singularity (Score 1) 356

Mod parent down. Hawking radiation cannot intervene in such a manner _inside_ the event horizon and prevent a singularity. It dissipates mass-energy outside an event horizon only. There is no known or even posited quantum effect that would magically prevent a singularity inside an extant event horizon in the way the parent poster fantasizes. Moreover, parent poster would have saved himself the embarrassment had he actually taken a mere cursory look at the paper, which discusses something completely different: the dissipation of the collapsing star's mass before an event horizon can ever form.

Comment Re:Folks need to see 'The Day After' (Score 1) 342

Mod parent up--he is spot on that they should have been used against the Chinese troops supporting the North. This was even more justifiable in terms of the massive suffering that would have been prevented than even the savings in lives lost from an alternative of ground invasion by the decisive strikes on Hiroshima and Nagasaki.

Slashdot Top Deals

New York... when civilization falls apart, remember, we were way ahead of you. - David Letterman

Working...