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Re: [vox] [ot] Damn - Slashdot rejections!
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Re: [vox] [ot] Damn - Slashdot rejections!



begin Micah Cowan <micah@cowan.name> 
> nbs writes:
>  > 
>  > Oh well... I tried.
>  > 
>  > I submitted the following three articles, which SOME of you might find
>  > interesting, even if the Slashdot editors didn't. ;)
>  > (Excuse the long, ugly URLs.  Blame Yahoo! News)
>  > 
>  > 
>  > 
>  > Planes Have Impact on Ground Temperature 
>  > 
>  >   http://news.yahoo.com/news?tmpl=story2&cid=585&ncid=585&e=9&u=/nm/20020807/sc_nm/science_temperature_dc_1
>  > 
> 
> I'm not saying I think they're wrong...  but, really, is comparing the
> results of only a single three-day period of "no contrails" to thirty
> periods of "contrails" supposed to be scientific?
> 
> I agree that they're a good indication, but the results are hardly
> conclusive...
> 
> Sorry... One of my pet peeves is unscientific science.
> 
> -Micah

wasn't going to comment, but guess i will.

some strange science has been coming from australia recently.  a
physicist down there claims to be able to show the 2nd law of
thermodynamics to be consistantly violated on a macroscopic time scale
for a very nearly macroscopic system.   i've seen no comment on this
work other than the announcement, which says something.

usually when someone makes an outrageous claim, like "newton's laws are
complete garbage", it'll be met with one of two reactions:

1. no comment.  everyone is just too embarrased for the researcher to
   say anything.  besides, the person is a crank, and you can't reason
   with cranks.

2. very strong words "that is the most stupid, idiotic thing i've ever
   heard in my life, and you're a nutcase", added with scientific
   evidence.

the thermo thing fell into category 1.  i haven't seen any comment on
it, which prolly means people have looked at the evidence and figured
that the evidence was so poor that nobody in their right mind would take
the guy seriously.


as for the thing at hand, people have been speculating about a
non-constant c for over 60 years.  the thing about SR and GR is that not
only are the theories mathematically complicated, very often it's nearly
impossible to interpret results correctly, even when you have the
correct result.


an amusing example would be a blunder that einstein himself made and
believed in till the day he died.  he showed that black holes don't
exist by taking a black hole spacetime and making a change of
coordinates to make the singularity disappear.  this puts two throats
together, effectively creating a wormhole (since called an einstein
rosen bridge).   and this is certainly allowable, since GR is invariant
under diffeomophisms.

however, you can imagine 2 space travelers, running around their ship
like chickens without a head because their starship is falling into a
blackhole, trying to make the appropriate coordinate system change
before they hit the singularity.  the fact is, all the coordinate
systems in the world won't help them.  if there's a singularity at the
center, it'll be there, whether you scribble calculations on a piece of
paper or not (ala "my name is simon").

the point is, things are very difficult to interpret with GR.  even for
the people who use GR on a day to day basis.

is the speed of light constant?  no.  light traveling in non-vaccuo will
move at a speed different than c.  in fact, if you take the ratio of
this speed and c, you'll get the index of refraction.  the "n" in
snell's law.  without the changing speed of light, your eye glasses
would be utterly useless.  of course, this isn't what that researcher
was talking about.

as another example, the speed of light can be measured to be different
from c even in a vacuum.  try to do a web search on the "shapiro effect"
or "the time delay of light".    there's an excellent book called "was
einstein right" that goes into the shapiro effect in depth.  it's
written by an experimentalist and while it's technical, it's
non-calculational.

the notion of "speed" is really very strange one in GR to begin with.

i'm guessing the guy is a crank.  there are certain topics which, if
someone brings them up, the "crank-o-meter" will begin to rise
dramatically.  i've always found john baez "crackpot index" to be a good
rule of thumb:

http://math.ucr.edu/home/baez/crackpot.html

pete

-- 
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