New York Times: I Was Promised Flying Cars
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 do indeed have many things that even a short time ago would have been considered impossible. I wonder how many inventions lie in wait for the understanding of one of these other forces of nature. Maybe everything isn’t as impossible as it seems.
It seems to me that the trouble we have with harnessing the other three forces of nature is most related to our inability to measure them. We are wizards with electromagnetism because we can very acutely measure what is happening. We don’t have so much skill with the other forces.
You might expect that, all these years after Newton, we might have a good measure of his gravitational constant, G. As the authors of a new paper on the topic note, there are plenty of reasons to want a good measure of G “given the relevance of the gravitational constant in several fields ranging from cosmology to particle physics, and in the absence of a complete theory linking gravity to other forces.”
Yet most of our measurements of G come from an updated version of a device designed by Henry Cavendish back in the 1700s. And rather annoyingly, these measurements don’t agree with each other—they’re all close to a single value, but their error bars don’t consistently overlap. Now, researchers have made a new measurement of G using a method that certainly wasn’t available in the 1700s: interference between clouds of ultracold atoms. And the value that they have come up with doesn’t agree with many of the other measurements, either.
Better measurements will be the key to unlocking the potential of the other forces.1 That’s why we should be excited about advances in measurement technology even if they do not have immediate practical applications, like recent improvements to atomic clocks. The new NIST-F2 atomic clock is three times as accurate as the clock it replaces; the new clock is accurate within 1 second over 300 million years. Obviously we don’t need that kind of accuracy for most daily activities. But the thing about new technology is that it isn’t always clear ahead of time how it might be used.
Nist.gov: A New Era for Atomic Clocks
Improved atomic clocks obviously will benefit widely used technologies that have long relied on precision timekeeping, such as communications and GPS positioning. But the new atomic clocks are becoming so extraordinarily precise that they are likely also to be used as extremely sensitive detectors for many things besides time.
For example, the frequency (“ticking rate”) of atomic clocks is altered slightly by gravity, magnetic fields, electrical fields, force, motion, temperature and other phenomena. In today’s conventional atomic clocks, those frequency changes are errors to be tightly controlled. In next-generation atomic clocks, the frequency changes are measured to such a fine degree that the clocks could become world-class instruments for measuring gravity, magnetic and electrical fields, force, motion, temperature and many other quantities.
Just like being able to measure a goal or performance on a project is the key to improving it.↩