201
the probability of finding a particle
in a particular place and state.
His German colleague Werner
Heisenberg showed that there
was an inherent uncertainty to
the values of place and momentum,
which was initially thought to be a
problem of measurement, but later
found to be fundamental to the
structure of the universe. A strange
picture was emerging of a warped,
relative space-time with particles
of matter smeared across it in the
form of probability waves.
Splitting the atom
New Zealander Ernest Rutherford
first showed that an atom is made
mostly of space, with a small,
dense nucleus and electrons in
orbit around it. He explained
certain forms of radioactivity as the
splitting of this nucleus. Chemist
Linus Pauling took this new picture
of an atom and used the ideas of
quantum physics to explain how
atoms bonded to each another. In
the process, he showed how the
discipline of chemistry was, in
reality, a subsection of physics. By
the 1930s, physicists were working
on ways to unlock the energy in
the atom, and in the US, J. Robert
Oppenheimer led the Manhattan
Project, which was to produce the
first nuclear weapons.The universe expands
Up to the 1920s, nebulae were
thought to be clouds of gas or dust
within our own galaxy, the Milky
Way, which comprised the entire
known universe. Then American
astronomer Edwin Hubble
discovered that these nebulae
were in fact distant galaxies. Theuniverse was suddenly enormously
bigger than anyone had thought.
Hubble further found that the
universe was expanding in all
directions. Belgian priest and
physicist Georges Lemaître
proposed that the universe had
expanded from a “primeval atom.”
This was to become the Big Bang
theory. A further puzzle was
uncovered when astronomer Fritz
Zwicky coined the term “dark
matter” to explain why the Coma
galaxy cluster appeared to contain
400 times as much mass (as seen
from its gravity) as he could explain
from the observable stars. Not only
was matter not quite what it had
been thought to be, but much of it
was not even directly detectable.
It was clear that there were
still major holes in scientific
understanding. ■A PARADIGM SHIFT
1929
1930
1931 1935 1939
1934 1936 1942
Edwin Hubble finds
that the universe
is expanding.Subrahmanyan
Chandrasekhar
describes black holes.Georges Lemaître
suggests that the
universe began as a
primeval atom.Konrad Lorenz
explains the basis of
animal instinct.Linus Pauling writes
The Nature of the
Chemical Bond, which
uses the ideas of
quantum physics to
explain chemistry.Fritz Zwicky
proposes the existence
of dark matter.Alan Turing
describes the Universal
Turing Machine,
a programmable
computer.J. Robert Oppenheimer
takes on the
Manhattan Project
to develop the
atomic bomb.