They did it! Scientists at CERN have finally found convincing evidence for the Higgs. I’ve been trying out a new Higgs explanation. Let me know what you think:
The story begins in 1932 with the discovery of the neutron. This was an amazing and important discovery for a lot of reasons. It made sense of all the different isotopes scientists had discovered since the early 1900s. It led in a very direct way to even more isotopes and to nuclear fission (just in time for World War II). And it also opened the window to a new fundamental force.
Two forces are quite familiar to us. Gravity caused Newton to get conked with the apple (not really, probably) and causes the Moon to stay in orbit around the Earth. Electromagnetism does, well, just about everything else. Friction, curve balls, chemical reactions, the weather, radio waves, and the color of the sky are all the results of electromagnetism. Gravity and electromagnetism are so good at explaining just about everything that we didn’t even notice the other two forces until the 1930s.
First came the strong nuclear force (at first just called the nuclear force, because it was the only one). It holds the nucleus of atoms together. It has to be strong because the nucleus, with positive protons and neutral neutrons, could never stay together with just electromagnetism. In fact, when a neutron breaks a nucleus in two, it’s the overwhelming electromagnetic repulsion that causes the huge release of “nuclear” energy.
But eventually scientists realized there was another force in nature, something they called the weak nuclear force. That force caused the newly-discovered neutrons to decay when they sit all alone. Put a billion neutrons in a box, and in around fifteen minutes half of them will have decayed into a proton, an electron, and another particle called a neutrino. It took around thirty years for scientists to really understand the weak nuclear force. When they finally did, they received a shock. When looked at in the right way, the weak nuclear force looked a lot like electromagnetism. Eventually they renamed the whole works the “electroweak interaction.”
Though they look a lot alike mathematically, in reality electromagnetism and the weak interaction are quite distinct, one easy to tell from the other. Why?
Imagine you are a fish living in a very strange ocean. This ocean has no surface, no floor, no islands or continents or anything at all to break it up. It is nothing but water as far as the fins can stretch. All you’ve ever experienced is this ocean all around you all the time.
This is exactly the situation scientists say we are in. In the 1960s a large number of scientists (including one named – wait for it – Higgs!) proposed that we are living in an ocean of sorts, an ocean they call the Higgs field.
To go back to our fish analogy, how would you ever learn that you’re living in water? Well, one way would be to do experiments. Maybe this water affects some objects more or less than others. Maybe some objects feel the stickiness of water more than other objects.
Higgs and others proposed that the reason the weak interaction looks so different from ordinary electricity is that the particles responsible for the weak interaction, called the “W” (for weak, get it?) and the Z (for – OK, I don’t know what that’s for. I guess they were running out of letters), “stick” to the Higgs field. This stickiness we see as heaviness. The photon, on the other hand, which carries electromagnetic signals, doesn’t stick to the Higgs field at all. It passes right through, as if the Higgs isn’t there at all. This different behavior in the Higgs ocean leads to all the differences between electromagnetism and the weak force as we observe them.
But wait, there’s more. Scientists realized that not only the W and Z’s would be sticky in the Higgs field. Almost every other particle, including electrons, protons and neutrons (well, really the quarks that protons and neutrons are made of) would be sticky, too. The reason any of us weigh anything, it turns out, is because the stuff we’re made of feels this invisible Higgs ocean all the time!
This may sound crazy, but here’s the thing: Scientists predicted the W and Z particles must exist as massive particles present whenever the weak force is at work. Then those scientists went looking for W and the Z, in just the way theory said they ought to be found. What happened? The W’s and Z’s were really there! Doing so well with the W’s and Z’s gave scientists confidence that they were on to something, and so they starting looking for the Higgs, a much harder thing to find. In fact, it’s been nearly fifty years since ideas about the Higgs first formed. Finally, scientists were able to build the right tools to find the Higgs, and lo and behold, there it is!
It’s an amazing time for physics. The discovery of the Higgs after all these years may well mean we’re on the verge of new breakthroughs that we never dreamed of. Only time can tell what the scientists will discover next.
Science is a long and beautifully connected story of discovery after discovery, each one revealing a bit more of this amazing universe. Congratulations go out to all those scientists who’ve given us another precious bit called the Higgs. Now, what can we discover next?