If you could fast-forward some 1,000 years and peek into a college science textbook from the year 3000, what would you see? I doubt you’d find many of our current theories still in there. Today, the Standard Model of particle physics and Albert Einstein’s general relativity seem like twin pinnacles of human intellectual achievement. Tomorrow, they might be cast into history’s dustbin, relegated to mere footnotes alongside old ideas about the Earth-centred solar system and the deterministic Universe. It would be a humbling sight – and a tremendously reassuring one.
Given the choice, I would prefer to see our current theories not validated. I’d much rather live in a Universe where we discover that today’s view of physics is comically naïve. If I am so lucky as to live to see deep new discoveries about the true nature of reality, I hope to find them bizarre and shocking. In 1,000 years, physics and mathematics will probably have progressed so far that the very nature of the questions will be incomprehensible to us. Researchers will have moved on to bigger, more mind-blowing questions that today’s deepest thinkers are not yet even equipped to ask.
Consider the recent total solar eclipse that transfixed North America. Thousands of years ago, such an event might have seemed like a clue about the divine order of the world or a portent of the future. Modern astronomers recognise the eclipse as a cosmic coincidence – the Sun and the Moon just happen to be the same size in our sky – but one that is useful for studying the plasma physics of the solar atmosphere.
How will physicists in the year 3000 view our current consternation over the apparent coincidences within the Standard Model of particle physics? The charge of the electron and the proton are thought to be unrelated arbitrary constants, yet they balance exactly. The mass of the Higgs boson would be many thousands of times heavier if two other seemingly unrelated constants didn’t match to many decimal places. Are these clues that will help us unravel the secrets of nature, or are they simply more misleading coincidences that future physicists will chuckle over at our expense?
If we really could get our hands on that future science text, I like to think we would have just about zero chance of understanding it. If you have the opportunity to visit the year 3000, don’t waste your time sneaking into university libraries. You’d be better off snatching children’s books from kindergartens if you want to have any chance of comprehending them. Better yet, you can peek into the future right now by exploring the biggest things we already know that we don’t know about the Universe.
For starters, there is much that we do not understand about the nature of matter. We don’t know why there is both matter and antimatter, and why there’s much more of one than the other. Most of the observable Universe consists of four basic particles called fermions (the up quark, down quark, electron and neutrino). They each have two cousins that mimic them in nearly every way, but are much more massive. Why? We have no idea.
Even this limited knowledge is relevant only to the 5 per cent of the Universe made of these familiar particles. Physicists refer to the ‘dark matter’ and ‘dark energy’ that make up that 95 per cent. In this case, dark means not just that we do not see these components, but that we have no idea what they are or where they come from. Nearly all we know about dark matter is that there is about five times as much of it as what we used to think of as normal matter – the stuff that makes up you and me and ice cream and stars. The bulk of the energy density of the Universe is devoted to dark energy, about which we know even less, except that it’s busy pulling the Universe apart.
Connecting the mysteries of matter and energy are questions about the nature of gravity. Quantum mechanics and general relativity don’t agree about what happens when gravity gets extremely strong, such as inside black holes. This discrepancy is an exotic symptom of a serious gap between our two most successful physics theories.
Behind the curtain loom even larger mysteries. What – if anything – is outside the observable Universe? What – if anything – came before the Big Bang? There are also open questions about basic elements of existence. What are space and time? We have learned recently that space is much more than an abstract backdrop on which events of the Universe play out. It bends in the presence of mass, and ripples with gravitational waves. Some theorists propose that space can be quantised, built up out of discrete units. Such speculations sound to us like science fiction, but might make physicists in the year 3000 smirk at our cluelessness.
And even these questions can understate how little we know. The most dramatic insights are likely to appear not in places where our ignorance is obvious, but where we are not even aware of our conceptual errors. Humans have a long track record of overgeneralising. When J J Thompson discovered the electron in 1897, he imagined it as the building block of all matter, simply because it was the first fundamental particle discovered. Now, as we wonder what dark matter is made of, the leading candidates are undiscovered particles known as WIMPs (for weakly interacting massive particles), because they fit neatly into our current theories. Maybe so… or maybe our extrapolations will again fail, and future discoveries will upend bedrock assumptions.
I get impatient to have the cosmic mysteries solved right now. You probably do, too. After all, the answers must exist, and the clues to piece them together are likely all around us. Confronting our profound ignorance is frustrating, but it is also crucial. It is the force driving us forward. Real progress in understanding the Universe requires recognising that every instance of our ignorance is a scientific opportunity, and then resolving to chip away at it. Advancing our understanding requires venturing beyond the edifice of current thought and opening our minds to new ideas.
Someone might reasonably ask: why bother? Does it matter how many cousins the electron has, or whether the Universe is finite or infinite? To me, those seemingly abstract questions help us answer the deepest questions we all face: why are we here, and how should we live our lives? Think how different our modern mindset is from that of 1,000 years ago. Learning that Earth is not the centre of the cosmos changed our view of our significance, for scientists and non-scientists alike. Discovering the basic structures and ordering principles of the Universe will reveal something even more fundamental about our place in the natural world.
That is why it’s important to fund the basic research that lets us stumble into great new discoveries. By acknowledging what we don’t know – the areas where we have no idea, really – we give direction to this stumbling. Then we can press, slowly but inexorably, toward a future in which our children will read about astonishing new discoveries in the colourful pages of a kindergarten picture book.
From ‘We Have No Idea: A Guide to the Unknown Universe’ by Jorge Cham and Daniel Whiteson, published by Riverhead Books, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2017 by Jorge Cham and Daniel Whiteson.