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I recently listened to The 4% Universe by Richard Panek and then returned to A Universe From Nothing by Lawrence Krauss. The story of how we discovered both dark matter and dark energy, and what these two mysteries might mean for our future, is breathtaking, a brilliant story of scientific exploration and surprise. What sticks out the most for me from this tale was something David Deutsch wrote in The Beginning of Infinity. The universe is filled with evidence.
When scientists found that they could not only see supernovae in distant galaxies, but actually monitor them over the course of days and weeks, and that this monitoring program would reveal information about the actual distance of the supernovae, they were taking advantage of this richness. Consider, the light from these supernovae has been part of the light striking our planet for millennia. That light is even now falling on our rooftops. Information is everywhere. All we need to make use of that information is a good idea (or, really, several of them).
And that brings me to the point of this entry. I think Lawrence Krauss is a fine writer and scientist, and I agree with him on many things. But after The Beginning of Infinity, I find that certain of his attitudes strike me as clearly misguided. Krauss likes to say, “We live at a special time, the only time when we can know that we live at a special time.” What he means is that in the future all evidence of dark energy, universal expansion, and all the other amazing discoveries we’ve made in the last 100 years or so, will have disappeared over the cosmic horizon. Cosmologists, if there are any a trillion years from now, will have no way of knowing that they live in an expanding universe dominated by dark energy. Even worse, as their one remaining galaxy cluster slowly ages, the visible universe, and any life it contains, must blink out until all is cold and dark.
This is unduly pessimistic, on several accounts.
Firstt, why does Krauss assume that our knowledge will die? Why couldn’t it be that our discoveries of the past 100 years will spread, along with our technology and in some form ourselves, to the far reaches of our galaxy and even beyond? The shortness of human life is no real barrier, as death and sickness are not universal truths but only problems we’ve not yet solved. In fact, there is no law of physics preventing our knowledge from spreading at or just below the speed of light.
Second, why does Krauss assume that we know all that we will ever know about dark matter and dark energy? Not so long ago, it was stated emphatically that we will never know what stars are made of, because we can never go and get a piece of one. Then scientists started collecting evidence, and, lo and behold, the answer was there in the star’s own light. In fact, that discovery lead in a straight line to the modern discoveries of dark matter and dark energy that Panek and Krauss discuss in their excellent books.
How can Krauss know that similar discoveries regarding dark matter and dark energy are not waiting to be made? If the history of science tells us anything, it tells us that new phenomena always lead to new understanding. As David Deutsch wrote, in a sentence both straightforward and profound, “We cannot know what we have not yet discovered.”
Finally, how can Krauss know that the discovery of dark matter and dark energy will not give people a new way of not just understanding, but in fact controlling the universe? Many modern science writers, including Krauss, Richard Dawkins, and others, lament the fact that we humans are so impressed with our own evolution of conscious intelligence. If intelligence were just another adaptation, like an elephant’s trunk, they’d be right. But our conscious intelligence isn’t like that. It is different because it has the ability to transform the world in utterly unpredictable ways.
Deutsch wrote that if you find a block of gold anywhere in the universe, you know the block was formed either by a supernova, or by a person. But if you find a good explanation, you know a person had to create it. A supernova alone could not. He also wrote that life on this planet will disappear, unless people decide otherwise.
This is the point. Unless people decide otherwise. The universe will grow cold and dark. Unless people decide otherwise. Unless the laws of physics prevent it (and how will we know unless we try), we can forge our own future in this universe. We need only to learn how.
Richard Dawkins wrote the afterward to Krauss’s very good book. He made a point that he and many others have made before. This new view of the universe may be depressing and bleak. So what. Get over it. The universe doesn’t owe us anything. While I agree with the hard-headed logic of this sentiment, I think it leaves out the obvious next step. We can make our own future. We can decide our fate. We can rage against the dying of the light and create a world that does suit our desires. Once again, we need only learn how.
So read both Panek and Krauss, good books full of wonderful ideas. But remember Deutsch’s principle of optimism. Problems are soluble, if we learn how.
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?