A Blip That Speaks of Our Place in the Universe
Cern European Pressphoto Agency
By LAWRENCE M. KRAUSS
Published: July 9, 2012
ASPEN, Colo. — Last week,
physicists around the world were glued to computers at very odd hours (I was at
a 1 a.m. physics “party” here with a large projection screen and dozens of
colleagues) to watch live as scientists at the Large Hadron Collider, outside Geneva, announced
that they had apparently found one of the most important missing pieces of the
jigsaw puzzle that is nature.
The “Higgs particle,” proposed almost 50 years
ago to allow for consistency between theoretical predictions and experimental
observations in elementary particle physics, appears to have been discovered — even as the detailed
nature of the discovery allows room for even more exotic revelations that may
be just around the corner.
It is natural for those not
deeply involved in the half-century quest for the Higgs to ask why they should
care about this seemingly esoteric discovery. There are three reasons.
First, it caps one of the
most remarkable intellectual adventures in human history — one that anyone
interested in the progress of knowledge should at least be aware of.
Second, it makes even more
remarkable the precarious accident that allowed our existence to form from
nothing — further proof that the universe of our senses is just the tip of a
vast, largely hidden cosmic iceberg.
And finally, the effort to
uncover this tiny particle represents the very best of what the process of
science can offer to modern civilization.
If one is a theoretical
physicist working on some idea late at night or at a blackboard with colleagues
over coffee one afternoon, it is almost terrifying to imagine that something
that you cook up in your mind might actually be real. It’s like staring at a
large jar and being asked to guess the number of jelly beans inside; if you
guess right, it seems too good to be true.
The prediction of the Higgs
particle accompanied a remarkable revolution that completely changed our
understanding of particle physics in the latter part of the 20th century.
Just 50 years ago, in spite
of the great advances of physics in the previous half century, we understood
only one of the four fundamental forces of nature — electromagnetism — as a
fully consistent quantum theory. In just one subsequent decade, however, not
only had three of the four known forces succumbed to our investigations, but a
new elegant unity of nature had been uncovered.
It was found that all of
the known forces could be described using a single mathematical framework — and
that two of the forces, electromagnetism and the weak force (which governs the
nuclear reactions that power the sun), were actually different manifestations
of a single underlying theory.
How could two such
different forces be related? After all, the photon, the particle that conveys
electromagnetism, has no mass, while the particles that convey the weak force
are very massive — almost 100 times as heavy as the particles that make up
atomic nuclei, a fact that explains why the weak force is weak.
What the British physicist
Peter Higgs and several others showed is that if there exists an otherwise
invisible background field permeating all of space, then the particles that
convey some force like electromagnetism can interact with this field and
effectively encounter resistance to their motion and slow down, like a swimmer
moving through molasses.
As a result, these
particles can behave as if they are heavy, as if they have a mass. The
physicist Steven Weinberg later applied this idea to a model of the weak and
electromagnetic forces previously proposed by Sheldon L. Glashow, and
everything fit together.
This idea can be extended
to the rest of particles in nature, including the protons and neutrons and
electrons that make up the atoms in our bodies. If some particle interacts more
strongly with this background field, it ends up acting heavier. If it interacts
more weakly, if acts lighter. If it doesn’t interact at all, like the photon,
it remains massless.
If anything sounds too good
to be true, this is it. The miracle of mass — indeed of our very existence,
because if not for the Higgs, there would be no stars, no planets and no people
— is possible because of some otherwise hidden background field whose only
purpose seems to be to allow the world to look the way it does.
Dr. Glashow, who along with
Dr. Weinberg won a Nobel Prize in Physics, later once
referred to this “Higgs field” as the “toilet” of modern physics because that’s
where all the ugly details that allow the marvelous beauty of the physical
world are hidden.
But relying on invisible
miracles is the stuff of religion, not science. To ascertain whether this
remarkable accident was real, physicists relied on another facet of the quantum
world.
Associated with every
background field is a particle, and if you pick a point in space and hit it
hard enough, you may whack out real particles. The trick is hitting it hard
enough over a small enough volume.
And that’s the rub. After
50 years of trying, including a failed attempt in this country to build an
accelerator to test these ideas, no sign of the Higgs had appeared. In fact, I
was betting against it, since a career in theoretical physics has taught me
that nature usually has a far richer imagination than we do.
Until last week.
Every second at the Large
Hadron Collider, enough data is generated to fill more than 1,000 one-terabyte
hard drives — more than the information in all the world’s libraries. The
logistics of filtering and analyzing the data to find the Higgs particle
peeking out under a mountain of noise, not to mention running the most complex
machine humans have ever built, is itself a triumph of technology and
computational wizardry of unprecedented magnitude.
The physicist Victor F.
Weisskopf — the colorful first director of CERN, the European Center for
Nuclear Research, which operates the collider — once described large particle
accelerators as the gothic cathedrals of our time. Like those beautiful
remnants of antiquity, accelerators require the cutting edge of technology,
they take decades or more to build, and they require the concerted efforts of
thousands of craftsmen and women. At CERN, each of the mammoth detectors used
to study collisions requires the work of thousands of physicists, from scores
of countries, speaking several dozen languages.
Most significantly perhaps,
cathedrals and colliders are both works of incomparable grandeur that celebrate
the beauty of being alive.
The apparent discovery of
the Higgs may not result in a better toaster or a faster car. But it provides a
remarkable celebration of the human mind’s capacity to uncover nature’s
secrets, and of the technology we have built to control them. Hidden in what
seems like empty space — indeed, like nothing, which is getting more
interesting all the time — are the very elements that allow for our existence.
By demonstrating that, last
week’s discovery will change our view of ourselves and our place in the
universe. Surely that is the hallmark of great music, great literature, great
art ...and great science.
