From: Dickey, Michael F (michael_f_dickey@groton.pfizer.com)
Date: Tue Jul 23 2002 - 12:21:20 MDT
"I was questioning Kaku's 'brilliance' because of his particular activism."
I read some of Kaku's non-fiction work, such as Hyperspace and visions, and
have been quite fond of his work, being a laymen. He even wrote recently in
another science mag (astronomy?) which he was featured as debating the
future of humanity and technology with some other mainstream physicists. As
I recall, his arguments were rather extropian.
However, when I found out he was leading the cassini protests I was quite
shocked and dissapointed. I still dont understand his motivation.
Robert Zubrin on Kaku -
Michio Kaku and anti-nuclear activists protesting probes with RTG's
This fact is disputed by anti-nuclear activists such as Professor Michio
Kaku, a string theorist from City College of New York, who have demonstrated
and filed lawsuits to attempt to block the launch of every recent
radioisotope-equipped probe. According to them, the launching of RTG's
represents an intolerable risk to the Earth's environment, because in the
event of a launch failure the plutonium contained by such devices could
break up on reentry and pollute the world. Furthermore, they maintain, such
devices are unnecessary. In a debate with NASA's former nuclear program
director Dr. Gary Bennett prior to the Galileo launch, for example,
Professor Kaku claimed that the mission could be just as well performed
powered by batteries instead.
In fact, the anti-nuclear activists are wrong on both counts. An RTG
contains about 100,00 curies (Ci) of plutonium-238. On a personal level this
is a nontrivial amount - you certainly wouldn't want it around your house -
but on a global level it is utterly insignificant. To put it in perspective,
if a launch were to fail and an RTG were to break up and be dispersed into
the world's biosphere (instead of staying intact and sinking as a solid
brick into the sub seabed Atlantic downrange from Cape Canaveral, which is
actually what would happen), it would release a radiological inventory
approximately 1/100th of 1 percent as great as that released by a typical
nuclear bomb test. It would represent an even smaller fraction of the
radiological release emitted by each and every one of the half dozen or so
sunken U.S. and Soviet nuclear submarines (such as the Thresher) currently
rusting away on the ocean floor. Furthermore, the plutonium-238 used in RTGs
is not the right kind to use in atomic bombs and has a half-life of 88
years, so it does not last as a long-lived feature of the Earth's
environment. In RTGs, it is present not as a metal, but as plutonium oxide,
in which form it is chemically inert. The statement that a reentering RTG
could represent a significant threat to the Earth's environment is simply
untrue.
Equally wrong is Professor Kaku's assertion that outer solar system probes
could be powered by batteries. To see how silly this idea is, consider the
Galileo spacecraft, which is powered by two 300-W RTGs and warmed by several
hundred 1-W RHUs, for about 800W in all. For the sake of discussion, let's
grant this is overkill and assume that the mission really could get by with
just 200 W of power. Good primary batteries can store about 300W-h/kg.
Galileo left Earth in October 1989, and as of August 1998, or 70,000 hours
later, was still functioning. At 300 W-h/kg, that would be about 47,000 kg
of batteries! (The two RTGs currently on board weigh about 60kg each; the
RHU mass is negligible.) Of course, with this much battery mass, the power
requirement would be much greater than 200 W, since the spacecraft would
require additional power to keep the batteries from freezing. To keep 47,000
kg of batteries (about 5,000 gallons worth) warm, we would probably need to
expend at least 2,000 W. But to supply that power, we would need 470,000 kg
of batteries, which would need 20,000 W to keep warm, which would require
4,700,000 kg of batteries, and so on. The mission is clearly impossible on
battery power.
In fact, outer solar system exploration needs to move in the direction of
significantly higher power levels if it is to be executed efficiently. Not
only do we need RTG's, we need to move beyond them to actual space nuclear
power reactors that use nuclear fission, rather than mere radioisotope
decay, to generate tens or hundreds of kilowatts. The reason for this is
very simple. On Earth, it has been said, knowledge is power. IN the outer
solar system, power is knowledge.
Robert Zubrin - Entering Space - page 176-177
Michael Dickey
-----Original Message-----
From: Amara Graps [mailto:amara@amara.com]
Sent: Tuesday, July 23, 2002 3:55 AM
To: extropians@extropy.org
Subject: Re: Scientific output
Regular Expression:
>The brilliance of Michio Kaku is not in the volume of his scientific
>output (by which I take it you mean research), but in his ability to
>explain the cutting edge of theoretical physics to a reader of average
>intelligence.
I can't judge Kaku's writing because I've not read it. I can't
judge Kaku's scientific papers because I've not read those either,
nor can I judge his abilities as a teacher.
I was questioning Kaku's 'brilliance' because of his particular
activism. (that's why I gave those Google links) To me, that spoke
volumes about him (what he said, how he went about it, etc),
and I had no interest in looking at other output from him.
Amara
LEGAL NOTICE
Unless expressly stated otherwise, this message is confidential and may be privileged. It is intended for the addressee(s) only. Access to this E-mail by anyone else is unauthorized. If you are not an addressee, any disclosure or copying of the contents of this E-mail or any action taken (or not taken) in reliance on it is unauthorized and may be unlawful. If you are not an addressee, please inform the sender immediately.
This archive was generated by hypermail 2.1.5 : Sat Nov 02 2002 - 09:15:38 MST