The most interesting recent physics news is that the Large Hadron Collider at CERN, in Geneva, is finally working at its highest-ever design energy and intensity. Why that is so important is because it may at last allow the discovery of new particles—superpartners—that would enable formulating and testing a final theory underlying the physical universe.
As Max Planck immediately recognized when he discovered quantum theory over a century ago, the equations of the final theory should be expressed in terms of universal constants of nature, such as Newton’s gravitational constant G, Einstein’s universal speed of light c, and Planck’s constant h. The natural size of a universe is then tiny, about 10–33 cm, and the natural lifetime about 10–43 seconds, far from the sizes of our world. Physicists need to explain why our world is large and old and cold and dark. Quantum theory provides the opportunity to connect the Planck scales with our scales, our world, and our physical laws, because in quantum theory virtual particles of all masses enter the equations and mix scales.
But that only works if the underlying theory is what is called a supersymmetric one, with our familiar particles, such as quarks and electrons and force-mediating bosons each having a superpartner particle (squarks, selectrons, gluinos, etc.). In collisions at the LHC, the higher energy of the colliding particles turns into the masses of previously unknown particles via Einstein’s E=mc2.
The theory did not tell us how massive the superpartners should be. Naïvely, there were arguments that they should not be too heavy (“naturalness”), so they could be searched for with enthusiasm at every higher energy that became accessible, but so far they have not been found. In the past decade or so, string theory and M-theory have been better understood and now provide clues as to how heavy the superpartners should be. String theories and M-theories differ technically in ways not important for us here. To be mathematically consistent, and part of a quantum theory of gravity and the other forces, they must have nine or ten space dimensions (and one time dimension). To predict superpartner masses, they must be projected onto our world of three space dimensions, and there are known techniques for doing that.
The bottom line is that well-motivated string/M-theories do indeed predict that the LHC run (Run II), which started in late 2015 and is moving ahead strongly in 2016, should be able to produce and detect some superpartners, thus opening the door to the Planck-scale world and promoting study of a final theory to testable science. The news that the LHC works at its full energy and intensity and is expected to accumulate data for several years is a strong candidate for the most important scientific news of recent years.