PSAT Reading Practice Question 613

Question: 613

The Death of Physics—a scientist presents information on recent developments in physics. Written in 2015.
At the turn of the nineteenth century, a
prominent physicist stated that physics as a
field of study was finished due to the belief
that everything about the physical world
05had already been discovered. Newtonian
Mechanics had held sway for over two
hundred years and our understanding of the
atom had not advanced much beyond the
concepts of the ancient Greeks. The view of
10a static universe was the accepted construct
and humanity's ignorance was a kind of
simple bliss and arrogance.
This all changed soon after the turn of the
next century. A German patent clerk, Albert
15Einstein, turned Newtonian Mechanics on its
head and developed the Theory of Relativity
and the notion of space-time. In the 1920s,
women studying photographic plates of
various star systems took measurements that
20Edwin Hubble used to demonstrate that the
universe is not static at all, but is expanding
in all directions, no matter where you might
be; this became known as Hubble's Law.
Hubble's constant—the rate at which the
25universe is expanding—is currently estimated
to be 21 km/s per one million light-years
from Earth. This ushered in the notion of
the Big Bang as the singular beginning of an
expanding space-time and everything in it.
30As years went by, the precision of measuring
the age of the Universe since the Big Bang
kept evolving to a current estimate of 13.2
billion years. Arno Penzias and Robert Wilson
provided additional evidence for this view
35of cosmology when an antenna they were
adjusting in the 1960s detected a small
amount of radiation from every direction in
space.
Scientists also began to explore the world
40of the very small, and the field of quantum
mechanics was hatched. From a world of
fundamental particles that included only
protons, neutrons, and electrons, a never-
ending march toward more fundamental
45building blocks ensued, and now quarks,
leptons, bosons, gravitons, etc. have become
the particles that physicists use to try to
make sense out of the nano-world. The
recent discovery (2015) of the Higgs Boson
50at the Large Hadron Collider in Europe
created much excitement in the scientific
community. This particle and the Higgs Field
are responsible for giving every substance its
mass and had been elusive since Peter Higgs
55postulated their existence in 1964.
Where will this process end? Each time we
cause particles to collide at ever-increasing
energies, new constituents are created and
investigated. It is as if we continue to peel
60back the layers of an onion only to find more
layers that invite exploration. In the modern
era, the field of String Theory has been
posited, theorizing that the vibrations of tiny
string-like mechanisms provide the building
65blocks of all particles. From String Theory,
the idea of Multiple Universes has been
proposed and evidence of this mind-blowing
idea was reported in late 2015.
Now scientists insist that the "visible"
70universe only contains about 30% of what
is really out there, and the concepts of dark
matter and dark energy are invoked to
explain the motions of various large bodies
that permeate our universe. We are 120 years
75beyond the time when physics was declared
dead to any new inquiries. Now, the steady
arrival of new and exciting perspectives
and data from more precise and powerful
instruments and machines launch new
80explorations on a monthly basis. There is
nothing dead about the field of physics, and I
would claim it has never been more alive.

What is the purpose of the sentence in lines 59–61 ("It is as if . . . invite exploration")?

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