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object’s brightness accurately, and
they made visible objects that had
previously been too faint to detect,
such as the small, icy worlds of the
Kuiper belt beyond Neptune.Computing power
Fast, reliable computers and
an immense capacity for storing
data have been key not only to
the way that telescopes and their
instruments are constructed,
but also to making sense of the
astronomical data they collect.
One major project alone, the Sloan
Digital Sky Survey, has collected
information about 500 million
celestial objects since it began
in 2000. This database has been
used to create a three-dimensional
map showing how galaxies are
distributed across the universe,
revealing its largest structures.Computers are indispensable
to theorists, too. Huge computing
power makes it possible to gain
insight into what observations
are telling us about the way
the universe works by creating
simulations based on the laws of
physics. For example, computers
allow scientists to model ways in
which the solar system may have
formed and evolved.
Space exploration has now
pushed right out to the edge of
the solar system, and no region
of the planetary system remains
unexplored on some level. The
New Horizons mission passed
Pluto in 2015 and is moving through
the Kuiper belt, while the Voyager
spacecraft, launched back in 1977,
are now sending back data from
interstellar space. With the advent
of the internet, missions can alsobe followed in real time, as the latest
images from the Hubble Space
Telescope or the Curiosity rover on
Mars are made instantly available.Landmark discoveries
Of the many discoveries in recent
decades that have had an impact
on our understanding, three stand
out. The surprise finding in 1998
that the universe’s expansion is
accelerating showed that there
is a gap in fundamental theory.
By contrast, the detection of
gravitational waves in 2016
confirmed Einstein’s 100-year-old
theoretical prediction. Meanwhile,
the discovery of the first extrasolar
planet in 1995, and thousands more
since, has energized the search
for alien life. It is impossible even
to speculate where the next 20
years may lead. ■THE TRIUMPH OF TECHNOLOGY
1995
1998
2012
2013
2015
2016
N A S A’s Curiosity rover
lands on Mars and begins
to explore its surface.The European Southern
Observatory opens
its Atacama Large
Millimeter Array, a giant
radio telescope in Chile.After an 11-year journey,
N A S A’s New Horizons
spacecraft makes its closest
approach to Pluto, revealing
details of its icy surface.Cosmic expansion
is found to be accelerating,
suggesting the existence of a
mysterious “dark energy.”Swiss astronomers
Didier Queloz and
Michel Mayor
discover the first
exoplanet orbiting
a sunlike star.
The Ligo Scientific
Collaboration announces the
detection of gravitational
waves, confirming Einstein’s
general theory of relativity.