A plea to save "New Scientist"
Greg Egan
people get their information on scientific matters, and (IMHO) it does an
excellent job about 70% of the time. But the combination of a
sensationalist bent and a lack of basic knowledge by its writers (most
obviously in physics) is rendering it unreliable often enough to
constitute a real threat to the public understanding of science.
There are many areas in cosmology, fundamental physics and so on where
there are controversies over issues that are hotly contested by various
competent, highly educated and respected scientists, and I have no
quarrel with New Scientist publishing views on various sides of these
debates, even when those from the opposing camp would consider the claims
to be nonsense.
However, I really was gobsmacked by the level of scientific illiteracy in
the article "Fly by light" in the 9 September 2006 issue, concerning the
supposed "electromagnetic drive" of Roger Shawyer. If Shawyer's claims
have been accurately reported, they violate conservation of momentum.
This is not a contested matter; in its modern, relativistic form it is
accepted by every educated physicist on the planet. The writer of this
article, Justin Mullins, seems aware that conservation of momentum is
violated, but then churns out a lot of meaningless double-talk about
"reference frames" which he seems to think demonstrates that relativity
somehow comes to the rescue.
Mullins quotes one engineer who says Shawyer's claims are "a load of
bloody rubbish", but that's really not good enough, when the rest of the
article is full of apparent endorsements from various authorities. If
Mullins had tried, I'm sure he could have found someone to explain to him
exactly *why*, however clever Shawyer's design might be, the only
possible source of net thrust for this device would be the release of the
microwaves in a unidirectional beam, and that the ceiling on the thrust
imposed by relativity is P/c (where P is power), or 3.33 microNewtons per
kilowatt. As the article stands, it leaves readers with the impression
that while one engineer has raised some unspecified quibbles, it's quite
likely that Shawyer is correct.
I wrote a letter to the magazine politely pointing out the relevant
physics, but even in the event that this letter, or similar comments from
other physics-literate readers are published, the underlying problem
seems to be the editorial culture at the magazine that allows this kind
of article to appear in the first place. Maybe it's unrealistic to
demand that every science writer who covers a physics story have a
physics degree, but surely there's some level of quality control that can
be introduced, to ensure that claims that flatly contradict established
and uncontroversial physical principles are either clearly flagged to the
magazine's readers as such, or (in cases of perpetual motion machines,
magic anti-gravity devices, etc.) just not published at all.
So, this message is a plea to everyone who cares about the public
understanding of science. New Scientist has a very large readership, and
its reports are often quoted in the mainstream press as if they carried
the same authority as a peer-reviewed journal. I know that some people
think New Scientist is just a tabloid joke that should be written off as
beyond redemption, but I don't share that view; I don't believe its
mistakes come from bad faith or cynicism, but the editor and publisher
really need to get the message, both from the physics-literate portion of
their readership and the academic physics community, that they need to
raise their standards or risk squandering the opportunity that the
magazine's circulation and prestige provides.
If any of these issues matter to you, please read the article and -- if
it worries you even half as much as it worried me -- please write to the
magazine and let them know.
Greg Egan
BellT
news:2006091600151...@mail.netspace.net.au...
> New Scientist is a British-based publication where many thousands of lay
> people get their information on scientific matters, and (IMHO) it does an
> excellent job about 70% of the time.
> However, I really was gobsmacked by the level of scientific illiteracy in
> the article "Fly by light" in the 9 September 2006 issue, concerning the
> supposed "electromagnetic drive" of Roger Shawyer.
I feel the same way! I have posted in a thread in rec.arts.sf.science about
it. I am utterly shocked at how bad the science is, and how anyone who
took a high school physics class would immediately see the problem.
Not only does it violate conservation of momentum, but just about every
statement
(in the "theory") is very wrong. Special relativity describes em waves,
the microwaves travel at almost the speed of light, confusion between
group and phase velocity.... etc.
The worst error is perhaps their starting point.
F = q(E + vB)
and for the velocity of the particle above, they substitute the
group velocity of the electromagnetic wave. WTF!
Interested folks can check out the theory at:
http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf
Spud
> I feel the same way! I have posted in a thread in rec.arts.sf.science about
> it. I am utterly shocked at how bad the science is, and how anyone who
> took a high school physics class would immediately see the problem.
Why does the thruster work ?
Spud
BellT
news:1159391344.7...@i42g2000cwa.googlegroups.com...
Lot's of thrusters work. Engines are not rare.
I have not examined the actual thruster.
Offhand I would say that attaching a big honking power
supply (1.2kW) to a bunch of stuff could reasonable
produce a measureable force.
My criticism lies in the theoretical explanation, which
has many errors. I therefore conclude that whatever their
thruster is doing, it is not what they say the thruster is doing,
and it is my personal opinion that it likely that the fundamental
laws of physics are not being violated.
Oh No
>BellT wrote:
>> I feel the same way! I have posted in a thread in rec.arts.sf.science about
>> it. I am utterly shocked at how bad the science is, and how anyone who
>> took a high school physics class would immediately see the problem.
>
>Why does the thruster work ?
>
Perhaps there is a problem with the test procedure. They claim to
measure a thrust, but perhaps there is a counter thrust on the magnetron
which they are failing to measure. Or perhaps they are only measuring
forces on the ends of the guide, and ignoring sidewall force (which it
what it looks like). Of course in either case such a system could not
power a space craft. Or perhaps it does work, but em energy is being
pumped out the back somehow, and the analysis has not been given.
Regards
--
Charles Francis
substitute charles for NotI to email
Douglas Natelson
I would bet an enormous sum of money that it doesn't. In the article
the would-be inventor waves his hands about how once the thruster
starts moving its thrust drops. I suspect that this statement means
that the inventor is measuring the fluctuating noise floor of his
accelerometer. Does he show, even in his manuscript, a single scrap
of data? Like, say, a graph of thrust vs. microwave power? Of
course not.
Greg Egan
"Spud" <omega...@yahoo.co.uk> wrote:
> BellT wrote:
> > I feel the same way! I have posted in a thread in rec.arts.sf.science
about
> > it. I am utterly shocked at how bad the science is, and how anyone who
> > took a high school physics class would immediately see the problem.
>
> Why does the thruster work ?
>
> Spud
The tiny forces measured in the lab could easily be the result of thermal
effects (i.e. differential heating of the surrounding air), or mechanical
effects from the cooling system. There are probably significant
measurement errors as well, but who knows, since Shawyer puts no error
bars on the data.
Needless to say, none of these effects would be much help in moving
satellites around in space.