source: Big Questions Online
author: Frank Wilczek
Editors’ Note: It has been one year since scientists announced the discovery of a particle believed to be Higgs. Read this essay by a Nobel prize winner in physics and share your comments on ourFacebook page.
Imagine a planet encrusted with ice, beneath which a vast ocean lies. (Imagine Europa.)
Within that ocean a species of brilliant fish evolved. Those fish were so intelligent that they took up physics, and formulated the laws that govern motion. At first they derived quite complicated laws, because the motion of bodies within water is complicated.
One day, however, a genius among fish, call her Fish Newton, had a startling new idea. She proposed fundamental laws of motion––Newton’s laws––that are simpler and more beautiful than the laws the fish had derived directly from experience. She demonstrated mathematically that you could reproduce the observed motions from the new, simpler laws, if you assume that there is a space-filling medium that complicates things. She called it Ocean.
Of course our fish had been immersed in Ocean for eons, but without knowing it. Since it was ever-present, they took it for granted. They regarded it as an aspect of space itself––as mere emptiness. But Fish Newton invited them to consider that they might be immersed in a material medium.
Thus inspired, fish scientists set out to find the atoms of Fish Newton’s hypothetical medium. And soon they did!
That story is our own. We humans, like those fish, have been living within a material medium for millennia, without being consciously aware of it.
The first inkling of its existence came in the 1960s. By that time physicists had devised especially beautiful equations for describing elementary particles with zero mass. Nature likes those equations, too. The photons responsible for electromagnetism, the gravitons responsible for gravity, and the color gluons responsible for the strong force are all zero mass particles. Electromagnetism, gravity, and the strong force are three of the four fundamental interactions known to physics. The other is the weak force.
A problem arose, however, for the W and Z bosons, which are responsible for the weak force. Though they have many properties in common with photons and color gluons, Wand Z bosons have non-zero mass. So it appeared that one could not use the beautiful equations for zero mass particles to describe them. The situation grew desperate: The equations for particles with the properties of W and Z, when forced to accommodate non-zero mass, led to mathematical inconsistencies.
The right kind of cosmic medium could rescue the situation, however. Such a medium could slow down the motion of W and Z particles, and make them appear to have non-zero mass, even though their fundamental mass––that is, the mass they would exhibit in ideally empty space––is zero. Using that idea, theorists built a wonderfully successful account of all the phenomena of the weak interaction, fully worthy to stand beside our successful theories of the electromagnetic, strong, and gravitational interactions. Our laws of fundamental physics reached a qualitatively new level of completeness and economy.
The predictions of those “medium-based” laws got tested with the sharpest precision and in the most extreme conditions that experimenters could devise. They were eager to disprove them. The Swedish Academy of Sciences gives prizes for things like that! But the laws passed every test, with flying colors. This grand synthesis has been so successful, for so long, that it has become known as the Standard Model.
Of course, the success of the Standard Model gave circumstantial evidence for the cosmic medium it relies on. Nevertheless, until a few months ago a nagging question remained: What is that cosmic medium made from? No known particles had the right properties.
On July 4, 2012, scientists at the CERN laboratory, near Geneva, announced the discovery of a new particle that seemed as though it might have the required properties. Over the last few months, more detailed measurements have confirmed and sharpened the initial discovery. Several tough consistency checks came in positive. In March CERN declared victory. The main building block of our cosmic Ocean, the Higgs particle, has been successfully identified.
Why does it matter?
The discovery of the Higgs particle is, first and foremost, a ringing affirmation of fundamental harmony between Mind and Matter. Mind, in the form of human thought, was able to predict the existence of a qualitatively new form of Matter before ever having encountered it, based on esthetic preference for beautiful equations.
We plumb the depth of that Mind-Matter harmony if we meditate on the challenge the Higgs particle discovery posed.
The Higgs particle is heavy, couples poorly to matter, and is extremely unstable. (Its lifetime is much too short to be measured directly, but is inferred to be roughly 10-22sec.) To produce it, scientists had to plan, and then build, the Large Hadron Collider, or LHC. That machine is an extraordinary feat of engineering. The main ring, which houses counter-circulating beams of extremely energetic protons, is 27 kilometers around. The protons are moving at very nearly the speed of light, so they make the circuit about 10,000 times per second. Their paths must be controlled very accurately, using powerful, precisely machined, superconducting magnets. Superconductivity requires low temperatures, so the ring is held at just 2 degrees above absolute zero. Even intergalactic space, filled with the 2.7 degree microwave background, is hotter than that. Thus the LHC ring is the coldest extended region in the universe, unless of course some extraterrestrial civilization is doing similar tricks.
The proton beams are made to cross at a few points, where collisions can occur. The collisions are violent encounters. They reproduce densities of energy achieved when the universe was a mere microsecond old, close to the Big Bang. They make Little Bangs, from which hundreds of energetic particles emerge. Less than one collision per billion contains a Higgs particle. And those that do, don’t come labeled “Higgs particle here!” Far from it. As I mentioned previously, the Higgs particle is extremely unstable. One sees only the products of its decay. From those remnants––which, remember, are delivered mixed up with lots of other debris––one must reconstruct what happened well enough to identify the Higgs. Related QuestionsDoes Quantum Physics Make it Easier to Believe in God?Is Information the Basis of Reality?
From this description, I hope you’ll get the (correct) impression that the discovery of the Higgs particle built upon, and required, a tremendous foundation of prior knowledge. We relied on our mathematical equations to guide us in building the machine and to anticipate, in quantitative detail, 99.9999999 percent of what would happen when it ran, so we could concentrate on the interesting novelties. Our equations proved up to the task! This is profound testimony that Mind, in its mathematical productions, accurately reflects the system Matter lives by.
Confirmation of the idea that we live in a cosmic medium has two other, more specific philosophical consequences, as well.
We have learned that some of the observed peculiarities of elementary particles can be blamed on the cosmic medium they inhabit. We can work creatively with beautiful equations that seem to be––and that, taken literally, actually are–– “too good for this world” by imagining a simpler, emptier world where they hold, and devolving from there to here. Can we take that strategy further? Might most––or all?––of the apparent differences among elementary particles be due to the complicating influence of other cosmic media, made from heavier and more elusive Higgs-like particles?
Physicists have taken up that imaginative opportunity, with gusto. We can construct specific, attractive models whose basic equations obliterate the distinctions among strong, weak, and electromagnetic forces. These unified theories go well beyond the Standard Model. They predict the existence of new particles and forces, which could well be discovered within a few years, after the LHC is upgraded to run at higher energies. They are credible, because they also predict quantitative relationships among the observed forces that agree with existing measurements. Specifically, they predict the relative strengths of the strong, weak, and electromagnetic interactions, which are free parameters with the Standard Model itself. In this way, Einstein’s vague dreams of unification have begun to take on tangible, quantitative form.
The other implication is cosmological. Given that we live in a material medium, it is natural to ask whether that medium might change with time, or might have different properties elsewhere — just as our standard analogue, water, can boil into steam, or freeze into ice. Indeed, calculations show that the Higgs-particle medium that fills our universe today could not persist at arbitrarily high temperatures. It is like a liquid that “boils away.” Then the W and Z bosons lose their masses, and the operative laws of physics look different! That almost certainly occurred, during the earliest moments of the Big Bang.
Cosmologists have taken up these imaginative opportunities, also with gusto. Although the cosmic phase transition associated with the (now) known Higgs-particle medium was probably tame, other transitions of that sort could have had dramatic consequences. In particular, they might trigger periods of extremely rapid expansion––cosmic inflation. That has proved to be an extremely fruitful idea in early-universe cosmology.
Space-filling media with variable properties also encourage speculations that the laws of physics might operate quite differently in different locations. There is presently no direct evidence for any effect of that kind, but an inhomogeneous Multiverse is a logical possibility that no longer seems entirely fanciful.
In conclusion, coming back to Earth, I’d like to mention an aspect of the discovery I can only describe as moral. The scientific work leading to the Higgs particle discovery involved thousands of engineers and physicists, not to mention billions of taxpayers, from all over the world co-operating to pursue a common goal. For most of the highly gifted participants, it involved long, often frustrating and sometimes tedious labor, with modest prospects for personal reward. They did it, anyway, because they wanted to understand the world better, and to be part of something great. They did, and they were. In this we have seen, I think, an example of humanity at its best.
Can you imagine some works of art, or events, that would add to our appreciation of these discoveries? Music? Multimedia? Performances? Installations?
What does the beauty of the fundamental laws––which everyone who understands them senses––mean? Is it a lucky accident, a trick of perception, or something deeper?
Do the achievements of CERN, and of the scientific research enterprise in general, provide a model for creative human cooperation that we can build on, to address other, more immediate problems?