The
recent
finding of gravity waves produced by the merger
of two distant black holes has been taken as yet another confirmation
of Einstein's Theory of General Relativity. There have been various
such confirming measurements, including the gravitational redshift
and lensing of light and non-Newtonian, changes in the orbit of
Mercury. But the deeper significance of this latest discovery lies
in what it may say about the rival grand theory, quantum physics.
The Standard Model of modern physics has proven remarkably good at
accounting for the known elementary particles (fermions, hadrons and
bosons). The measurement of
the Higgs boson in 2012 was an astounding
confirmation of our most basic understanding of the origin of mass.
Despite the “spookiness”
of some of the predictions of quantum physics – such as quantum
entanglement – many of its strangest have
been verified.
Indeed,
the Standard Model is rather too perfect. It seems to account for
most of the basic parameters of matter and energy including three of
the four fundamental forces: —electromagnetic and the weak nuclear
(unified as electro-weak) and the strong nuclear interaction (which
holds together the atomic nucleus). But it cannot explain gravity,
dark matter or dark energy (thus leaveing
out 95% of what we believe to be the universe).
In trying to extend its reach – to achieve a grand unified theory
to include gravity –- physicists have so far failed to find the new
phenomenon that would hint at new physics in the form of
supersymmetry
or string theory. The Standard Model explains
what it does so perfectly that those seeking to take it further
cannot seem to find any of the discrepancies that might point the way
to a Grand Unified Theory of Everything.
General
Relativity, on the other hand, has been confirmed in every case. It
provides a coherent theory of the universe as framed by spacetime and
the speed of light. It does not explain the Big Bang or the
menagerie of fundamental particles. Rather, General Relativity
describes how mass interacts with space and across time. Mass
deforms spacetime and matter and energy – including gravity waves –
travel in straight lines along the bends. Einstein's famous equation
– the E=MC2 of Special Relativity – does not explain
why mass and energy are interchangeable but provides a way to measure
the transformation of one into the other within the limitation
imposed by the speed of light (which cannot be exceeded).
Relativity
is in essence a top-down theory. It begins with Einstein's grand
view of the very nature of spacetime, the basic fabric of the
universe. Quantum physics is more bottoms-up, seeking to discover
the basic pieces of reality. Relativity is a complete and verified
theory within its defined area. The Standard Model of quantum
physics is incomplete within its domain. It
may be that relativity is somehow the more fruitful way to think
about the universe. For Einstein, gravity is not a force, as it was
for Newton, but an artifact of mass bending spacetime. Quantum
physics again treats gravity as a force and seeks to find its
particle, the “graviton.” But what considerations may be drawn
from looking at quantum physics in light of relativity, instead of
trying to extend it to account for gravity? The key may lie in
pondering more deeply mass, light and the role of the observer.
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