hunter_hunted
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AS an astronomy-obsessed kid in the 1970s, I subsisted on a steady diet of science fiction. It promised a future filled with technological wonders: talking computers, bionic limbs, flying cars. Forty years later, though much of that future has arrived, it’s still missing what I consider its most important ingredient. Sure, we’ve got the iPhone’s Siri, and the Food and Drug Administration just approved a prosthetic arm controlled by signals from the brain — but where are our smooth-gliding flying machines, our Landspeeders (“Star Wars”) and airborne DeLoreans (“Back to the Future”)?
You may think that the absence of such cars speaks to a failure of engineering or distorted incentives in the marketplace. But the humbling truth is that we don’t have these vehicles because we still don’t know, even in principle, how to directly manipulate gravity. Indeed, the cars missing from our skies should serve to remind us that, to a degree rarely appreciated, we have surprisingly poor control over most of nature’s fundamental forces.
Physicists have compiled a comprehensive inventory of all the ways things can pull or push on other things, a complete itemization of nature’s forces. They’ve found just four.
The first is gravity, the force that keeps your feet on the ground. The second is electromagnetism, which is responsible for anything involving light or the arrangement of atoms. The third is the strong nuclear force, which binds protons and neutrons together inside every atom. And the fourth is the weak nuclear force, which (among other things) helps guide the fusion reactions that power stars.
And that’s it. Just four forces, just four ways to make things happen.
For all the power of modern science, we are masters of only one of these forces: electromagnetism. Laptops, smartphones, wirelessly connected thermostats, Google Glass — all our high-tech miracles exist because we’ve learned to control the electromagnetic force at the subtlest of levels. We routinely nudge electrons around circuits with the precision of an atomic watchmaker and coerce light to do our bidding with the barest of whispers. When it comes to electromagnetism, we have powers that are almost godlike.
With the other three, we’re not even close. Consider nuclear power plants. Yes, they rely on our remarkable knowledge of the strong and weak nuclear forces. But when all is said and done they simply use the heat generated by splitting atomic nuclei to boil water, which then spins turbines, which then generate electricity. That’s not so different from a 19th-century steam engine. Compared with the precision of an electron microscope (or even a grocery-store laser scanner), our handling of nuclear forces is still at the level of slamming rocks together.
The same is true of gravity. Obviously, we can make a plane fly by forcing air to flow over a wing, which generates the pressure to lift it off the ground. But the interaction of those air molecules is a result of electromagnetic forces. And the fuel we use to power planes (and blow rockets off the planet) is a result of our understanding of chemistry, which again is a matter of electromagnetism.
In other words: All our ways of flying involve a heavy-handed application of the electromagnetic force through fuels and engines. The noise, the danger, the pollution and the inefficiency that accompany the current ways of flying are a testament to our crude approach to defying gravity.
The problem is that we don’t really understand gravity at its most fundamental level. Much as a seemingly smooth shoreline is actually composed of quintillions of individual sand grains, every aspect of the world — matter, energy and motion — is actually parceled into infinitesimal building blocks. The four forces that shape the world come in little packages, too. With electromagnetism and the nuclear forces, we understand how the parceled behavior — the quantum mechanics — of these forces works. And the digital culture we’ve built rests directly on our ability to understand and manipulate electromagnetism’s quantum manifestations.
But with gravity we remain in the dark. We have no theory of quantum gravity. And without the ability to manipulate the quantum gravitational world, we won’t be gliding around in the silky hush of hover-cars anytime soon. Instead we will have to fly the old-fashioned electromagnetic way.
The lesson here is that for all our technological powers, we are still constrained by the deepest structures underlying physical reality. If one force can be easily manipulated at room temperature but another requires the power of a cosmic explosion, then those are facts we just have to work with.
So the next time you’re squeezed in the middle seat in row 37 and your bones are vibrating with the whine of the giant engines, remember: The fault is not with the airline, but with the universe.
http://www.nytimes.com/2014/06/08/o...romised-flying-cars.html?hp&rref=opinion&_r=0
You may think that the absence of such cars speaks to a failure of engineering or distorted incentives in the marketplace. But the humbling truth is that we don’t have these vehicles because we still don’t know, even in principle, how to directly manipulate gravity. Indeed, the cars missing from our skies should serve to remind us that, to a degree rarely appreciated, we have surprisingly poor control over most of nature’s fundamental forces.
Physicists have compiled a comprehensive inventory of all the ways things can pull or push on other things, a complete itemization of nature’s forces. They’ve found just four.
The first is gravity, the force that keeps your feet on the ground. The second is electromagnetism, which is responsible for anything involving light or the arrangement of atoms. The third is the strong nuclear force, which binds protons and neutrons together inside every atom. And the fourth is the weak nuclear force, which (among other things) helps guide the fusion reactions that power stars.
And that’s it. Just four forces, just four ways to make things happen.
For all the power of modern science, we are masters of only one of these forces: electromagnetism. Laptops, smartphones, wirelessly connected thermostats, Google Glass — all our high-tech miracles exist because we’ve learned to control the electromagnetic force at the subtlest of levels. We routinely nudge electrons around circuits with the precision of an atomic watchmaker and coerce light to do our bidding with the barest of whispers. When it comes to electromagnetism, we have powers that are almost godlike.
With the other three, we’re not even close. Consider nuclear power plants. Yes, they rely on our remarkable knowledge of the strong and weak nuclear forces. But when all is said and done they simply use the heat generated by splitting atomic nuclei to boil water, which then spins turbines, which then generate electricity. That’s not so different from a 19th-century steam engine. Compared with the precision of an electron microscope (or even a grocery-store laser scanner), our handling of nuclear forces is still at the level of slamming rocks together.
The same is true of gravity. Obviously, we can make a plane fly by forcing air to flow over a wing, which generates the pressure to lift it off the ground. But the interaction of those air molecules is a result of electromagnetic forces. And the fuel we use to power planes (and blow rockets off the planet) is a result of our understanding of chemistry, which again is a matter of electromagnetism.
In other words: All our ways of flying involve a heavy-handed application of the electromagnetic force through fuels and engines. The noise, the danger, the pollution and the inefficiency that accompany the current ways of flying are a testament to our crude approach to defying gravity.
The problem is that we don’t really understand gravity at its most fundamental level. Much as a seemingly smooth shoreline is actually composed of quintillions of individual sand grains, every aspect of the world — matter, energy and motion — is actually parceled into infinitesimal building blocks. The four forces that shape the world come in little packages, too. With electromagnetism and the nuclear forces, we understand how the parceled behavior — the quantum mechanics — of these forces works. And the digital culture we’ve built rests directly on our ability to understand and manipulate electromagnetism’s quantum manifestations.
But with gravity we remain in the dark. We have no theory of quantum gravity. And without the ability to manipulate the quantum gravitational world, we won’t be gliding around in the silky hush of hover-cars anytime soon. Instead we will have to fly the old-fashioned electromagnetic way.
The lesson here is that for all our technological powers, we are still constrained by the deepest structures underlying physical reality. If one force can be easily manipulated at room temperature but another requires the power of a cosmic explosion, then those are facts we just have to work with.
So the next time you’re squeezed in the middle seat in row 37 and your bones are vibrating with the whine of the giant engines, remember: The fault is not with the airline, but with the universe.
http://www.nytimes.com/2014/06/08/o...romised-flying-cars.html?hp&rref=opinion&_r=0
