258
M
ost major discoveries
in astronomy have
been made possible by
advances in technology. Recent
developments have provided
powerful tools to collect radiation
from space and to process vast
amounts of data, and the pace
of discovery has accelerated at a
breathtaking rate. Microelectronics
and computing capability, in
particular, have opened up new
possibilities over the last 40 years.Telescopes and detectors
The New Technology Telescope
(NTT) opened by the European
Southern Observatory (ESO) in
the Chilean Andes in 1989 is
an example of a telescope with
revolutionary innovations that have
subsequently become standard
equipment. Its main and secondarymirrors are flexible, but kept
precisely in shape by a network
of computer-controlled supports
called actuators.
ESO’s choice of Chile was part
of the trend for astronomers to
scour the world, testing for the
best sites where the air is clear,
still, and dry, and the sky free
from light pollution. Another
major center for astronomy was
established at the summit of the
volcano Mauna Kea on the Big
Island of Hawaii in 1967. This prime
site is now home to 13 telescopes.
Until the early 1970s, all
astronomical imaging was carried
out by means of conventional
photography. Then, in the mid-
1970s, a completely new way of
recording an image electronically
became a practical reality. This
was the charge-coupled device(CCD). CCDs are electronic circuits
with light-sensitive pixels that
generate electrical charges when
light photons land on them. They
are far superior to photography for
sensing faint light and recording anINTRODUCTION
1977
1979
1990
1995
1980
1986
The Hubble Space
Telescope enters orbit.
It provides the best-ever
images in the visible and
near-visible spectrum.US cosmologist Alan
Guth develops the idea
that the early universe
experienced a period
of rapid inflation.US astronomer Vera Rubin
publishes data showing
that the rotational speeds of
galaxies indicate the presence
of invisible “dark matter.”American Frank Shu
and colleagues present
a new model for
star formation.NASA launches
the two Voyager
spacecraft on a
mission to tour the
outer planets.
The first brown dwarfs
are detected, confirming
a theoretical prediction
made in 1962 by
Shiv S. Kumar.We’re going to need a
definitive quantum theory
of gravity, which is part of
a grand unified theory—it’s
the main missing piece.
Kip Thorne