A Step Farther Out (32 page)

But—fusion makes neutrons. Neutrons are what's needed to "recharge" spent fuel elements. Spent fuel elements, whether "recharged" or not, are so dangerous that they're safe: that is, they can be shipped about in huge containers stressed to withstand hundreds of g's, and nobody is going to open one of those things. With "recharging" there is never a point in the fuel cycle where weapons-grade material exists; the Pu concentration in a "recharged" fuel element will be around 5% of the oxide (while weapons-grade is about 90% enriched metallic) so that even if a demented terrorist group stole the fuel elements they'd be useless. (Oh, sure, they'd be dangerous, but so would the equivalent weight of TNT or plastique.)

At any rate, the concept is fascinating, and provides one bit of evidence for
my
basic thesis: that we are not doomed, the Club of Rome is wrong, and mankind has a very good chance at "Survival with Style."

Now, in keeping with the title of this book, let's get far out.

In Blish's classic
Cities In Space
series one basic element was antiagathic drugs: a pharmacology that cures death by reversing the effects of aging. Now in principle such things must be possible: certainly it must be possible to take a human being at some arbitrary stage of development and stimulate continuous regeneration so the system never "wears out." "In principle" is not practice, though; nobody knows how to do this.

However, Dr. Allan Goldstein of the University of Texas Medical Branch, Galveston, may well have taken several giant steps down that road. Dr. Goldstein, with Dr. Abraham White at Albert Einstein University, some years ago began work on immunological deficiencies in humans. All our textbooks tell us that the thymus gland, that lump on the breastbone, degenerates at about age 40 to 50. The older textbooks say the function of the gland is unknown; bolder spirits even asserted that it was useless, something like a vermiform appendix. That turns out not to be the case.

Human beings have two periods of severe danger: in childhood, before the immune system develops; and in old age, when the immune system deteriorates. In both those times we are vulnerable to various cancers, infectious diseases, and auto-immune disorders. Next, let us plot the levels of thymosin in the blood at various ages. (Thymosin is one of the secretions of the thymus gland.)

__________

Figure 27

 
10
¹²
Watts = 1 terrawatt or TW.
Inertial confinement: pellets of Deuterated polyethylene about 100 microns in diameter (1 micron = 1/25,000 inches) are bombarded with particles.

__________

The results are interesting: as the thymus gland vanishes, which it does until at age 40 only about 10% remains, and at age 80 it is virtually gone, the thymosin level falls, and our susceptibility to diseases of aging—those very ones that were so dangerous to us in childhood before the immune system developed—mounts rapidly.

Dr. Goldstein has used thymosin to treat children with immune system deficiencies. The results have been dramatic. Not many studies have been done: although several children were selected
for
this treatment, most died before the PDA gave permission for this very new drug to be used in humans.

The obvious next step is to try thymosin in persons age 40 and above, bringing the level up to what it was when they were 20 or so. That may take a while: it is estimated that it would cost $30 million in studies to get aspirin approved by the PDA even given what we already know about it; I wouldn't care to estimate what the costs of getting thymosin approved might be.

However, Dr. Goldstein has pretty well proved that the thymus gland is the "master gland" of the immune system, and that treatments with thymosin have been very useful for very young children with immunity disorders; that thymosin stimulates the development of certain cells which control phagocyte (while blood cell) cancer control activity—that is thymosin stimulates development of T-cells; T-cells somehow detect cancerous mutations and secrete a substance that brings phagocytes to the area; and the phagocytes eat up the cancer cells before they can multiply. Dr. Goldstein is emphatic in stating that thymosin is not the "magic bullet" for curing old age—but he strongly suspects that it can be useful in letting one age gracefully, without many of the pains and ailments so common in those over sixty.

He's also rather excited about all the developments in biochemistry and immunology. We are on the threshold of a new era in medicine. Understanding the immune system will of course make transplant technology much more reliable; may provide the key to cancer, and almost certainly will help keep patients alive long enough for other cancer treatments to be effective; and may well be the means for all of us to stay alive gracefully at least to the biblical three score and ten.

I have always had the view (not original with me) that the human organism is designed to self-destruct shortly after age 40. In a tribal society we ought to have the good grace to die when our children reach child-bearing age, with a few of us hanging around to be tribal elders, but most getting out of the way. Primitive communities which don't have lots of old people have more food for young ones, and their tribes increase. Modern technology changes this; now technology may find a way to overcome the self-destruct mechanism; and I find it no surprise to discover that our immunological master gland quietly vanishes about the time we're forty years old . . .

I wonder if the PDA will ever let physicians give thymosin (which is already used in treatment of cancer patients and young children) to normal people of middle age? I think I could find a number of volunteers.

Stepping a bit further out, alas, we take a step backward. According to Dr. Albert Ghiorso of Lawrence Berkeley Laboratories, we have
not
found element 126 and the "magic island of stability." Pity.

Dr. Ghiorso is probably the discover of element 104.1 say probably, because the Russians like to claim they found it first. I haven't space to review all the evidence. The upshot is that an international committee has been appointed, three Soviets, three Americans, and three neutrals. The committee has never met, but it is supposed to decide who, the Americans or the Soviets, gets to name 104. (As of 1978 it still has yet to meet-—JEP)

Meanwhile, Ghiorso has reviewed the evidence of the Florida State-Oak Ridge National Laboratory collaboration of Cahill and Gentry, which had hoped to find element 126 in primordial samples (the Soviets were searching for it in very old stained glass window leads) and found it wanting. Working from the other direction—if you can't find it in nature, can you make it?—Lawrence Laboratories and the Soviets at Dubna have been bombarding
²⁴⁸
Curium 96 with
⁴⁸
Calcium
₂₀
in an attempt to create super-heavies—and found none.

It's a great pity because I've just finished a science fiction novel whose plot depends on the discovery of superheavies; but all is not lost. It's true that we haven't found any natural superheavy elements, and best efforts haven't made any, but the search is still on and they're still theoretically possible.

Finally: what makes the Sun shine? It does, you know. Some theorists now wish it didn't. (Sure: that would kill us all, but doggone it, it sure wrecks good theories.., .)

Open any astrophysics or intermediate astronomy textbook, and you'll see confidently asserted a series of equations showing where the Sun gets its energy. Take four protons (hydrogen nuclei) and squeeze like mad; outcome four alpha particles (helium nuclei) plus two positrons plus two neutrinos. Adding the mass/energies of the input protons and subtracting out the masses of the output discloses some mass missing: enough to generate 25 million electron Volts, and thus the Sun shines.

So, a number of years ago, theoretical astrophysicists devised an experiment which would confirm this so generally accepted theory. It wasn't supposed to be an exciting experiment; but after all, we know more about the Sun than any other star, most of our astrophysics theories are deduced from stellar observations and most of those are of the Sun, and it always helps to have confirming experiments of basic theory. Hans Bethe settled it theoretically back in 1939, but it couldn't hurt to do an experiment even if this was the best understood aspect of astrophysics.

So, out in the old Homestake mine, was installed 100,000 gallons of perchloroethylene, C
₂
C1
₄
, and a very elaborate system for counting what happened when neutrinos struck the chlorine. (That generates argon.)

The
³⁷
Chlorine to
³⁷
Argon reaction expected from solar neutrinos was worked out by Dr. John Bahcall, Professor of Natural Sciences, Institute for Advanced Study about fifteen years ago. The unit is the "SNU" (pronounced "snoo"), about 10
^-36
captures per target atom per second: not very many, meaning that one needs a
lot
of
³⁷
Cl and a long time before you expect to see anything happen.

Raymond Davis and John Evans of Brookhaven National Laboratory worked out the actual test equipment, which involves finding 15 argon atoms per month in that immense tank of cleaning fluid. They have also tested the procedure, injecting known numbers of argon atoms into the system and recovering them. To the best of everyone's knowledge that experiment ought to work, and the neutrino capture rate in the tank ought to be about 6 SNU.

The observed result: a maximum of 1.3 SNU, and possibly none at all. This is astounding. Has the Sun gone out?

Dr. Bahcall is a careful man. He wanted it clearly understood that he still believes the textbook proton-alpha reaction is the explanation for why the Sun shines. However, when pressed, he will discuss what he calls "cocktail party" theories: that is, theories that a scientist might put forth in a cocktail party, but which one has no business publishing in a serious journal.

"Unfortunately," Dr. Bahcall told us, "a lot of cocktail party theories have been published. . ."

There are three major classes of theories to explain why we have observed no solar neutrinos: those that horrify astronomers, those that horrify physicists, and those that drive both up the wall.

The astronomers like to think something happens to the neutrinos on the way here: they're produced all right, but they're a lot less stable than physicists thought they were.

After all, the only observations of neutrinos have been in paths from a few centimeters to a kilometer or so long; perhaps over longer distances they decay into something else. Most physicists don't care much for that theory.

Physicists, meanwhile, have always felt that astronomers don't really understand stars as well as they think they do. Thus, Dr. Bahcall
says,
the failure of the standard theory just proves to physicists that they're right in being skeptical about what astronomers say. (Not that Bahcall himself has this attitude, but it is widespread.)

The result, anyway, has been what Bahcall describes as a theoretical orgy, mostly of "cocktail party" theories. Item: the Sun has "gone out" and periodically does so, reigniting after a period of gravitational collapse. Item: there's a black hole of around 1% of the Sun's mass dead center in our star, and the Sun shines because matter falling into the hole gives off energy, there's no fusion in there at all. Item (a theory that really drives astronomers nuts): suppose all the heavy elements in the Sun are concentrated in the outer layers (for reasons no one can give); then the results would be consistent with neutrino observation.

Whatever is the explanation, there's probably a Nobel Prize in it, which may explain why the Soviets are spending enormous sums, really a
lot
of money, on solar neutrino experiments. They're scaling up the Davis experiment by a factor of 10 in a tunnel under a mountain (these things need to be down deep to keep the cosmic ray counts low enough so that the solar neutrinos won't be hidden in a fog of interactions).

There's one final possibility, strange, but not out of sight: that the Sun operates, not on the

4P—>4α+2
_e
⁺
+2ν
_e
+25 meV

reaction I described earlier, but through the PeP reaction: a proton plus an electron plus another proton yields deuterium (heavy hydrogen) plus
one
neutrino i.e.,

P+e
^-
+P—> 
²
D
₁
+ν
_e

which as you can see produces just half the number of neutrinos, and they're at a lower energy level too, so that the expected SNU should be about 0.3—and that's just consistent with the observed data. (NOTE: there's no proof that we have found
any
solar neutrinos; but the likely level is in the order of 1 SNU.)

Now the astronomers will not like it if the Sun turns out to run on PeP; but their unhappiness is as nothing compared to what will result if experiment shows no solar neutrinos at all. Lower than 0.3 SNU requires something really far-out, strange, new, different, a theoretical restructuring along the lines of Einstein's work.