540
Book Reviews
The new book under review reports a conference organized in 1964 April to
discuss Marina-2 and other experiments. The book contains much material not
otherwise available and will be needed by all who are interested in either observational
or theoretical studies of the interplanetary plasma. The discussions, which are fully
reported, show the conference to have been lively and effective. Many of the
papers are of the review type but with great emphasis on exhibiting the data. The
coverage of the subject can best be revealed by the subdivisions which are
(a) phenomena observed in interplanetary space, (b) theories of interplanetary plasma
and fields, and of energetic particles, (c) origin of the solar wind and the corona,
(d) solar wind and the magnetosphere, and (e) solar-wind interaction with comets
and the Moon. There are twenty-eight papers by about thirty authors. The various
papers and discussions are tied together into a book by the Foreword written by
S. Chapman who, in a sense, originated it all.
C. W. ALLEN
Giant Meteorites
E. L. Krinov
(Pergamon Press, pp. 397, E5)
Most geophysicists have now ventured far enough into astronomy to realise that
meteorites are going to play a significant part in their long term theories concerning
the universe. The Earth’s core is well believed to consist of iron, largely because
those outside bodies that fall on the Earth are sometimes iron meteorites and sometimes stony objects. Recently the cold-accretion theories of Professor Urey have
been reconciled with that large body of geological opinion which desires an initial
liquid Earth by the metallurgical studies that have been made on iron meteorites.
The etch-patterns show that iron meteorites, which are supposed to be formed by
the break-up of small asteroids formed by cold-accretion like the Earth, indicate
that the iron has been melted and has cooled quickly. This could not possibly have
happened with the radioactive heating of our known warmers, potassium, uranium
and thorium, but it would be possible if there was a mystery element on the scene.
The mystery element could well be AIZ6,which would decompose to magnesium
and therefore be too difficult to observe. A half-life of one million years is proposed
for AlZ6and this means that we can have both cold-accretion which is supported by
the existence of light elements on Earth, together with an originally molten earth,
which is in accordance with all the facts of geological investigation.
It is therefore important that we should all learn about the evidence of
meteorites-and this book is one of the better and easily read primers on the subject.
The history of the discovery of large meteorite craters is fascinatingly displayed and
at the same time Dr Krinov gives us a detailed factual account of what has been
found, and what is mere conjecture. For those who do not know such things, it
is important to learn that some meteorite craters are formed by lumps of material
hitting the ground, like the pits left by shrapnel on buildings. The massive holes,
however, like that in Arizona, are due to a high speed projectile from outer space
that hit the Earth and had to get rid of so much energy quickly that it exploded
and left a giant crater as its gravestone. That is about all it left, except some fine
traces of highly pulverised material, because the impact caused everything, including
the iron and the neighbouring rock to be broken up. They talk, in the jargon of the
trade, of ‘ meteorite flour ’.
Book Reviews
541
The Barringer meteorite, which conveniently fell in a flat part of Arizona, is a
mile or so in diameter. For many years the Barringer family have tried to locate
the million ton block of iron, which they supposed made the crater. However,
modern thought suggests that their riches are dispersed as a fine rain over the
surrounding desert.
The Russians have been blessed with two good impacts in this century. The
Tunguska fell in 1908 but was not followed up quickly. Later research has shown
that it must have been a large explosion-type meteorite fall, but it is a pity the Czar
did not organise an earlier expedition than those that have discovered the facts so
far obtained.
The Sikhote-Mine iron meteorite shower, which also fell in a fairly remote place
in Russia, was on the other hand covered beautifully by all the efforts that a wellpersuaded powerful government could organise. The results (in spite of a certain
confusion because about half the samples were shuffled due to a train accident on
the way to Moscow) are a most excellent account of how the smaller lumps of iron
stay put after forming a crater, while the larger pieces split up on impact, so that we
are left with the paradox of small craters and large specimens, and large craters
with nothing but a mass of fine fragments.
The book does not stop at the Russian craters. You can find all the details of
craters that are many kilometres in diameter. The Canadians have used air photographs to pinpoint many new meteorite impacts with the Earth, and for those who
like records, the largest is probably 440 km in diameter. In case any research
student wishing to pursue this subject is averse to cold weather, there is a very good
looking prospect in Ghana, about 15 km diameter, and the Asantahene in Ghana
will no doubt tell him all about the difficulties of checking on this particular crater
T. F. GASKELL
Photographic Atlas of the Moon
Z. Kopal
(Academic Press, 1965, f6.8s.Od.)
In view of the present need for detailed maps of the lunar surface the U.S.A.F.
Aeronautical Chart and Information Center sponsored in 1960 a programme of
lunar photography to be carried out at the Pic du Midi Observatory, by a team led
by Professor Z. Kopal, from the University of Manchester. Photographs were
made on 9tinch roll film with a K-22 aerial camera, and from them 300 metre
contour charts of the moon have been constructed.
The Photographic Atlas of the Moon consists of a selection of over 200 prints
selected from the total available, together with nine frames from the series obtained
by the American probe, Ranger VII. The photographs are preceded by some notes
on the experimental problems encountered and by three introductory chapters
providing information about the physical properties of the Moon, the first of which
deals with the characteristics of the orbit and librations, the mass and density of the
Moon and the inferences about internal conditions which can be drawn from them.
This chapter concludes with a discussion of the possibilities of a gaseous lunar
atmosphere.
More controversial matters are dealt with in the second chapter which, after
describing the common surface features of the Moon, considers the origins of the
major ones, and also of domes, rilles and wrinkle ridges. Many of the internal