Geoscience Reference
In-Depth Information
such methods the periodicity of cratering could be corroborated, and
if three or four craters could be tied to specific extinctions, the
Raup-Shoemaker impact-kill curve (see Figure 24) could be roughly
calibrated and at least its overall shape determined, giving graphic
form to a scientific revolution.
We have seen how a young geologist in Italy, studying something
else, decided to bring home for his father a specimen that captured
one of the major events in earth history. Thus was launched a scien-
tific partnership that, conjoined with the work of hundreds of pro-
ponents and opponents alike, led to the solution of a great mystery.
Today we have gone about as far as science can go in corroborating
the notion that the impact of a meteorite caused the extinction of
the dinosaurs. But as always, answering one set of questions raises
others, and we are left pondering the true role of impact. As even its
bitterest opponents have to admit, the Alvarez theory has brought
geology not only a new set of questions, but a greatly improved set
of sampling techniques and analytical methods for answering them.
Paleontologists collect much larger samples and subject them to sta-
tistical tests. Today geologists know how to find and identify terres-
trial craters. These are the hallmarks of a fertile theory.
In 1996, science writer John Horgan published a highly contro-
versial topic,
The End of Science,
15
in which he argued that such dis-
ciplines as physics, cosmology, evolutionary biology, social science,
and chaos theory, have run into intellectual cul-de-sacs, are no
longer productive, and therefore have come to their natural end.
Whether or not one is persuaded by his argument, it is significant
that Horgan mentions not a single example from the earth sciences.
Far from coming to an end, beginning with plate tectonics in the
1960s, moving on to incorporate the advances of the space age, con-
tinuing today with the exploration of the Alvarez theory, and pro-
ceeding on tomorrow to determine the true place of impact and the
causes of mass extinction, geology is in its golden age.
