In 1916 Albert Einstein predicted gravitational waves. In 2017 the Nobel Prize committee awarded a group of scientists the award in physics for making the first direct measurement of gravitational waves. Previously they had only been inferred indirectly.

So, what does this mean? Who cares? What it means is that we are progressing technologically to levels not thought possible in the past. When Einstein predicted gravitational waves, it was said that they would be so weak that we would never be able to measure them. That was before we even knew that anything with the mass of black holes existed. It was before we had computers and many of the other technological devices that we commonly use today, like lasers. We should care because it means that nothing at the technological level seems impossible.

So, what is a gravitational wave? Think about a bathtub full of water that is left undisturbed for long enough such that the surface is perfectly still. Now, poke your finger into one end of the water. You will see a wave move away from your finger and move to the other end of the tub. If the wave starts out small, it may never reach the other end of the tub. Einstein predicted that the universe was like the tub, and any matter (like a star) moving would act like your finger, causing a gravitational wave to be sent through the universe. The problem is that the force of gravity is so weak that it seemed impossible to measure this wave. It would be like measuring the wave at one end of your tub caused by a mosquito landing on the other end.

What pieces of the puzzle allowed us to measure gravitational waves? First, there was the discovery of black holes. The mass of these objects was much greater than anything envisioned during the early 1900s. This would be equivalent to discovering an elephant-sized mosquito. However, a single black hole isn't going to be moving fast enough to produce a significant wave. With computers, scientists were able to simulate various scenarios of large masses that might produce gravitational waves. With lasers and very high-speed computers, scientists learned how to measure very small changes in a position of a test object with an incredible accuracy of time. With two measurement devices, placed sufficiently far apart, each would see the wave at slightly different times.

The measurements observed were compared with various computer simulations to determine that they saw two black holes colliding. They were also able to determine that the event occurred in the southern skies about 1.3 billion years ago.

This scientific result and advancement in technology was the result of research by American scientists at a cost of about $620M. Given today's turmoil, I hope that Americans feel that it is worth it, and would like to remind people that the money went to jobs for Americans in America. The benefit to society is as yet unknown.

Some interesting websites to learn more about these waves: https://spaceplace.nasa.gov/gravitational-waves/en/, http://news.nationalgeographic.com/2017/10/gravitational-waves-discovered-neutronstars-pictures-science/, and https://www.washingtonpost.com/news/speakingof-science/wp/2017/10/16/scientists-detect-gravitational-waves-from-a-new-kind-of-nova-sparking-a-new-era-in-astronomy/?utm_term=.ade3dc2b56be