The Science Book

268

T

he second half of the
20th century saw rapidly
improving technology
being employed in almost every
field of science, from telescopes to
chemical analysis. New technology
has widened the possibilities
for calculation and experiment.
The first computers were built
in the 1940s, and a new science,
Artificial Intelligence, has emerged.
CERN’s Large Hadron Collider—a
particle accelerator—is the biggest
piece of scientific equipment ever
made. Powerful microscopes have
allowed the first direct glimpses
of atoms, while new telescopes
have revealed planets beyond our
solar system. By the 21st century,
science has become largely a
team activity, involving ever
more expensive apparatus and
interdisciplinary cooperation.

The code of life

At the University of Chicago

in 1953, American chemists

Harold Urey and Stanley Miller

set up an ingenious experiment

to find out whether life could have

started on Earth when lightning

sparked chemical reactions in

the atmosphere. In the same

year, two molecular biologists—

American James Watson and Briton

Francis Crick—in a race against

rival teams in the US and Soviet

Union, figured out the molecular

structure of deoxyribonucleic acid,

or DNA, providing the key to the

genetic code of life, which would

lead less than half a century later

to the complete mapping of the

human genome.

Armed with new knowledge

about the genetic mechanism,

American biologist Lynn Margulis

proposed the apparently absurd

theory that some organisms can

be absorbed by others, while both

continue to flourish, and that this

process had produced the complex

cells of all multicellular life forms.

After years of scepticism, she

was vindicated by discoveries in

genetics made 20 years after her

proposal. American microbiologist

Michael Syvanen showed how

genes can jump from one species

to another, while in the 1990s, the

old Lamarckian idea that acquired

characteristics can be passed

on gained new traction with

the discovery of epigenetics.

Knowledge of the mechanisms

by which evolution can take place

was becoming far richer.

By the end of the century,

American Craig Venter, fresh from

running his own human genome

INTRODUCTION

1946

1948

1953

1957

1951

1953

1961

James Watson and

Francis Crick discover

the chemical

structure

of DNA.

Richard Feynman works

on the new discipline

of quantum

electrodynamics.

Barbara McClintock

demonstrates genetic

recombination,

showing how genes

can move around on

a chromosome.

Charles Keeling

shows that the

concentration of

carbon dioxide in the

air is increasing.

Harold Urey and Stanley

Miller demonstrate a

possible chemical

mechanism for the

origin of life.

Fred Hoyle describes

how new elements

are made in stars.

Sheldon Glashow

presents a new

symmetry model for

electroweak

interactions.

Hugh Everett III is

the first to propose

the many-worlds

interpretation

(MWI) of quantum

physics.

1961