2017-10-09

On the Nobel Prize for Gravitational Waves

This is a short post about the news from last week, that the Nobel Prize in Physics went to 3 of the founders of the LIGO project that first observed gravitational waves. I was quite happy to see the news, for several reasons. One of the PIs, Rainer Weiss, is an emeritus professor from MIT, so there was the alma mater pride factor there; plus, that professor, along with the two other co-laureates, are all quite old, and it would have been a real shame if they hadn't survived to be recognized by the Nobel Prize committee for this incredible work, so it really was time for them to be recognized as such. From an applied science perspective, the amount of high-precision science and engineering they had to do, building laser systems, mirrors, and large-scale interferometers to measure atomic-scale and smaller displacements where quantum effects are important, has been amazing and will undoubtedly influence future technological development in those areas, even as gravitational waves themselves are at energy scales that are far too small to be useful in the near future (though people used to say that about quantum mechanics, and then transistors came about, so it's always better to be open to the possibility, while being mindful that this particular possibility is more remote).

Mostly, though, I'm thrilled to see this discovery being recognized from the perspective of fundamental science. My research is in fluctuational electrodynamics, which means that I deal with the propagation and scattering of electromagnetic fields at small length scales as they originate from quantum or thermal fluctuating atomic or electronic sources. Thus, all I think about on a daily basis is really electromagnetic interactions (and occasionally quantum exchange effects). But then, most physicists, with the exception of high-energy physicists (who study very short-ranged weak & strong interactions anyway), tend to make use of electromagnetism almost exclusively in their research, especially on the experimental side, as any spectroscopy, interferometry, and so on, would necessarily involve the propagation and scattering of light. In fact, if I think about how humans sense the world around them, vision is of course electromagnetic in nature, but so are hearing (detection of pressure waves caused by scattering of atoms and molecules in the air via short-range electromagnetic repulsion from atoms and molecules in the ear) and touch (short-range electromagnetic forces between atoms and molecules on the skin and a given surface), while electrical signals travel through neurons in the body by virtue of electromagnetic forces. Thus, in the context of sensing and understanding the world around us through truly long-range interactions, gravitational waves are fundamentally different, and it's weird to think that the interaction that keeps us on this planet can also be used in such a different way (i.e. propagating waves) to get information about faraway astronomical objects that wouldn't be available through purely electromagnetic means.

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