Date sent: Thu, 20 Mar 1997 14:13:54 -0500 (EST)
Priority: NORMAL


The following is a mass review of impact books by
Duncan Steel (Spaceguard Australia) which was
published in METEORITE! magazine, 1997 February issue.




Rain of Iron and Ice:
The Very Real Threat of Comet and Asteroid Bombardment.
Addison-Wesley, Reading, Massachussetts, 1996.
ISBN 0-201-48950-3

Fire on Earth: In Search of the Doomsday Asteroid.
Simon and Schuster, London, 1996.
ISBN 0-684-81689-X

Impact! The Threat of Comets and Asteroids.
Oxford University Press, New York, 1996.
ISBN 0-19-510105-7

The Three Big Bangs:
Comet Crashes, Exploding Stars, and the Creation of the
Addison-Wesley, Reading, Massachussetts, 1996
ISBN 0-201-40752-3

Asteroid: Earth Destroyer or New Frontier?
Plenum Press, New York, 1996.
ISBN 0-306-45408-4


The task of reviewing five books about asteroid and comet
impacts on the Earth, all published in 1996, is a
daunting one for me for various reasons. Of course the
shear volume to wade through is a Herculanean task
(following the legend quite closely, if you know your
mythology and bother to read all that I write below), and
on top of that if I am harshly critical then the reader
may ascribe this to churlishness, in view of the fact
that I published a book on this topic myself in 1995
("Rogue Asteroids and Doomsday Comets," Wiley, New York;
generously reviewed by Alan Gilmore in an earlier issue
of this magazine). On the other hand, having a batch of
books to review allows one to make comparisons,
simplifying things somewhat. And having written such a
book oneself, one has it on record how one thinks that
such a book should be arranged, and there is no call to
criticize the other authors for constructing a book which
differs from the way in which one WOULD have written it;
one has done, so that's that.

I had thought originally that I might start off by saying
that I welcomed the publication of these books, since
they get the story to a larger number of readers - and
it's an important story, dealing with the future (or not)
of humankind - and that's more significant than mere
financial matters, and in any case more books on the
topic would perhaps lead to more sales of my own book.
The problem I found, however, is that overall this is a
very poor set of publications, which will confuse many
readers, and misrepresent the situation rather badly.

But to look on the bright side, let me start with that by
Lewis. John Lewis is a Professor of Planetary Sciences
at the University of Arizona, and he has been a long-time
proponent of near-Earth objects (asteroids and comets) as
potential sources of raw materials for our exploitation
of space over the next few decades, and eventual solar
system colonization. He was the lead editor of "Resources
of Near-Earth Space" (University of Arizona Press, Tucson,
1993) and he has another trade book (apart from that
under review here) just published by Addison-Wesley:
"Mining the Sky" (ISBN 0-201-47959-1). He has not been
deeply involved in the work on NEOs as a threat, however,
and the only conference I can recall him attending on
this subject is that held at Erice in Sicily in April

What about the title, "Rain of Iron and Ice"?
Meteoritophiles might immediately be able to say: "Hold
it - most of the meteoritic influx is stony, not iron (or
ice from comets)." One must imagine that Lewis was too
taken with the alliteration of the title as it stands;
but on that score, wouldn't "Rain of Rock" be better?

Nevertheless Lewis does a good job in presenting various
facets of our knowledge of NEOs and the hazard they pose.
The book is readable and interesting, just so long as you
do not have too much background knowledge; if you do,
then you'll find that most pages contain an error or two,
many of them minor, but some major. If you're a physicist
then you should know that there is no such thing as the
fictitious unit "the degree Kelvin" which most
astronomers like to use (as in "The Three Degree
Background"); the unit is actually the Kelvin, period.
Lewis states that the mean distance of the Earth from the
Sun is 1.000 astronomical units; if he had written "1"
and not "1.000" then I wouldn't quibble, but actually one
astronomical unit is the semi-major axis (which is itself
slightly variable) of the terrestrial orbit, and the
Earth spends more time near aphelion than perihelion,
making the mean distance a little over one AU. More
worrying is the fact that Lewis mis-states various
historical "facts", such as believing that Comet Biela
broke apart on January 13, 1846 (it actually broke up
some years before, but was not seen at the time).

But those are indeed minor quibbles. My main objection
to the book is that it is out of date. Whilst published
in 1996, it was printed in December 1995. Thus one would
expect it to be up to date as of the middle of 1995, if
not later. However, in the text it is stated that about
200 near-Earth asteroids are being tracked, whereas in
fact the total is more than double that figure as I write
this. In his Table 1 Lewis gives the box score as in
October 1992 as being 216. Being three or four years out
of date would not be so bad if it were not for the fact
that NEA discoveries have incremented the number known by
such a large factor in that time. How could one keep up
to date?

Well, Lewis just could have walked down the corridor in
the Lunar and Planetary Laboratory and asked any member
of the Spacewatch team for the latest scorecard; after
all, they are responsible for many of the entries on it.

That table in Lewis's book is the only such insertion
therein, and there are no line drawings. There are a few
- but only a few - black and white photographs included,
so that illustrative material is not the book's strong
point. But it wins hands-down over the book by the
Gribbins, which has 264 pages in large type almost
suitable for the visually impaired on thick, spongey
paper in a blatant attempt to produce a book which
appears to be substantial. It wouldn't be so bad if the
reading was a delight, but disappointingly for authors
with such a substantial publication record this book is
rather poorly-written. In such circumstances some
pictures to break the monotony would have been
especially welcome.

Even worse than the prose is the Gribbins' poor grasp of
the facts. They mis-state the numbers of known NEAs, at
one point giving numbers of Atens, Apollos and Amors from
a decade ago (there's been a five-fold enhancement since)
before increasing their stated figures later (so that
the book is internally inconsistent) but never reaching
the actual level in 1996, or 1995 if that is when the
book was written. John Gribbin has some claims as a
physicist; why, then, does the book state on page 45 that
"the kinetic energy in each gram of any material
[travelling at 30 kilometres per second] is roughly the
same as the chemical energy released in the explosion of
a gram of TNT"? In fact the KE at 30 km/sec is over a
HUNDRED TIMES higher than the chemical energy of TNT.
Even simple things like the assignation of designations
to asteroids (1997 AA, 1997 AB etc.) is given
incorrectly; some letters are not used.

The level of authority of this book, then, is not good.
I started making marginal marks to denote each error
which I identified; they average more than one per page.
This was especially irksome to me since the Gribbins
promote strongly the minority view held by myself and a
handful of British solar system astronomers that the
present epoch (meaning the Holocene) is a more dangerous
period for impacts on the Earth than the longer-term
average, due to the trapping of a giant comet in a
cis-jovian orbit within the last 20,000 years, and its
subsequent break-up into myriad Earth-crossing
asteroids and large meteoroids. The Gribbins effectively
harm the investigation of that hypothesis by publishing a
book which is defective in many aspects.

That concept - the recent arrival in near-Earth space of
a giant comet - is taken up with gusto by Gerrit
Verschuur. This has already earned him the opprobrium of
several American astronomers who have little or no
understanding of what has been proposed, and the
supporting evidence. For this Verschuur has my
appreciation, and I also admire his attitude towards
life: he has eschewed tenure at U.S. universities in
order to make a living from writing and conducting
independent research (in radio astronomy, amongst other
areas). His book is rather better illustrated than any
of the other four volumes, with pertinent photographs,
graphs and tables being interspersed throughout the

Verschuur writes well, having had several notable books
published in the past, and I'm sure that he has more
under way. He has the right blend of academic/scientific
background coupled with writing ability. In all of
these books some mention of meteorites and their
classification is necessary, and that by Verschuur I
found to be the best.

That is not to say, however, that this book is faultless.
For example, Verschuur's account of the circumstances of
the various statements made about Comet Swift-Tuttle
since it returned to perihelion in 1992 is largely false.
Credit is given to some people who do not deserve it, and
not to others who do: for example, what about Ichiro
Hasegawa's role in all of this? One can tolerate the
World Series being called that, when very few countries
outside of North America play baseball, but in scientific
research almost all countries play the game and one
should not let the hoopla propagated in the U.S. blind
one to the truth. There are various other places in the
book where Verschuur gives erroneous accounts of history,
to my knowledge; but I guess that even if the actual
players involved were to write the history as they
went along, still the accounts would differ. Comet
Swift-Tuttle shows that!

Only about a third of the book by Dauber and Muller is
concerned with impacts on the Earth, and contrary to
their subtitle they discuss asteroids as well as comets.
Muller has a particular interest in comet impacts due
to his involvement in the Nemesis (Death Star)
hypothesis, a barely-tenable theory invented in an
attempt to explain the apparent 26-30 million year
periodicity of large impacts on the Earth, and he tries
to defend that hypothesis therein. Leaving that aside,
the section on terrestrial impacts is quite nicely
written, although with various mis-statements in places.
In particular the authors rather nicely emphasize the
importance of catastrophic change in both the physical
and biological sciences, discussing how evolutionary
biology is being affected by this belated recognition.
On the other hand, they give too much weight to the KT
boundary event (the death of the dinosaurs) and the huge
impact scar now recognized in Mexico, perhaps leaving one
with the impression that nothing much has happened in the
65 million years since then. We all know that small
rocks fall from the sky every year - why else would you
be reading this magazine? - and I would hope that you are
all convinced that larger rocks, maybe a kilometre in
size, hit the Earth to cause global catastrophes perhaps
once every 100,000 years. Mass extinction events like
that which caused the end of the dinosaur era, causing
the extinction of around 50 percent of the species then
living on our planet, are much less frequent; but there
have been at least two since then. For example, that 36
million years ago has recently been linked to a
newly-discovered crater 85 kilometres wide which covers
the whole of the southern end of Chesapeake Bay.

Illustration-wise, the Dauber and Muller boom is again
poorly-blessed, there being only a few black and white
photographs included. One cannot hope that all books
would be as sumptuously illustrated as Carl Sagan's "Pale
Blue Dot" (Random House, New York, 1994; see Chapters 17
and 18 for his discussion of the hazard posed by asteroid
and comet impacts, with many lovely colour pictures), but
in explaining material such as that covered in these
books a few line drawings, tables and graphs would help

I have left to last the book by Barnes-Svarney. I feel
really badly about this one, having helped her with
various magazine articles and several questions in recent
years. Quite simply, this is the worse "science" book I
have ever had the misfortune to read. I noted above that
in the Gribbins' book I was making an average of at least
one marginal mark per page to denote errors; for this
book the score rose above five. It is just junk. Get
this for a paragraph: "The list of meteorite associations
has grown in the past few decades as scientists discover
more and more about these visitors from space. Most of
the meteorites are associated with the orbits of comets,
with main-belt asteroids found primarily in between the
orbits of Mars and Jupiter, with Mars and the Moon, and
even, some claim, associations with interstellar space."
Barnes-Svarney's account of meteorite classes and the
implications of such would make the average reader of this
magazine gag. I feel aggrieved that, having supplied her
with an up-to-date list of NEAs every month for some
time, still she gave a figure which is years out of date.

OK, the reader might think, so Barnes-Svarney got a few
things wrong, but one cannot know about everything, can
one? (The answer is that, if one is writing a book for
general consumption, one has to do MUCH better than this;
this book is grossly misleading, a tissue of nonsense).
Let's take a look at a couple of things which are
literally "close to home" for Barnes-Svarney, who
lives in the state of New York:

(i) In several places she refers to "O.M. Mitchel, the
director of the Dudley Observatory in Albany, New York,
in 1868" (actually she gets his initals wrong twice).
Well now, (a) Good old Ormsby was associated with the
Cincinnati Observatory, not the Dudley; (b) The
publication she cites for the quotes given is dated 1851,
seventeen years before 1868; and in any case (c) Ormsby
was a prominent Union soldier in the Civil War, and died
of disease in 1862 in the warmer South.

(ii) The great Cape York iron meteorite well-known to so
may meteoritophiles due to the epic story of its
transport to New York earlier this century, along with
two massive fragments, is (according to Barnes-Svarney)
in the Hayden Planetarium. Maybe she should have taken
the trouble to go and take a look at it whilst writing
the book. It was moved more than a decade ago into the
Ross Hall of Meteorites of the American Museum of Natural
History. Yes, I know that it's just a wander diagonally
through the galleries of the AMNH, and not even any
stairs to climb, but you might be pretty annoyed to find
that out after you've paid the admission fee to the
Hayden Planetarium. If such simple things are not
checked, what hope is there?

I began by writing that a comparative review is a good
thing, so I guess it's come to the time to rank these
books. I'd give that by Verschuur 8 out of 10; Lewis 7;
Dauber and Muller (for the part on terrestrial impacts) 5;
the Gribbins 2 out of 10. Barnes-Svarney deserves, and
gets, a zero.


There has been such a blooming of books on this topic
that one imagines that many other publishers are bringing
their own out. It is turning into a real industry,
perhaps growing after the various TV programmes on the
topic due in early 1997, and then Steve Spielberg's
planned movie; and others. One other book I have been
told of (but not seen) is:

Doomsday Asteroid.
Promotheus Books, New York, 1996.
ISBN 1-57392-066-5.

Apparently Cox was the co-author of a 1964 book about
asteroids entitled "Islands in Space: The Challenge of
the Planetoids." I am told that the first part is a
general overview of the NEO threat, whilst the remaining
three parts discuss mining and colonizing the asteroids.

CCCMENU CCC for 1997