Amanda Gefter’s book Trespassing on Einstein’s Lawn is about her journey into the world of physics with her father. Throughout the book she and her father search for the ultimate building block of the universe. What is the smallest particle that forms the basis of all other particles? What aspect of the universe is constant among all scales and all perspectives? What constitutes reality in our universe?
From our perspective here on Earth, these questions seem like they should be strait-forward and easy to answer. However, once we start looking into the universe and observing more than what we can simply experience here on Earth, we begin to see that what we understand as reality is not as clear as it appears. The deeper we peer through space, the more we see strange phenomenon such as the curving of spacetime, and the more energy we put forward in the search of smaller and smaller particles, the more we find that matter seem to come and go and not behave as we expected.
Throughout their search, Gefter and her father look into the physics of various candidates for the ultimate building block of reality and meet many interesting scientists and physicists. From the beginning, one of Gefter’s favorite physicists was John Wheeler, and early on in his research he took down the idea that spacetime itself was the most basic unit of the universe. “Wheeler emphasized that spacetime couldn’t be reality’s ultimate ingredient, because at its highest resolution quantum mechanics and general relativity conspire to destroy it, warping its geometry until it isn’t geometry anymore.”
Over the last two years a principle predicted by Albert Einstein has been proven correct as we have discovered gravitational waves. These are ripples through spacetime caused by events of massive energy. The empty space of space, according to the theory of Einstein is not actually empty but is composed of what we have confusingly named spacetime. Our planets and everything in the universe permeates across and through this spacetime according to physics that Einstein helped describe. In her book, Gefter turns back to Wheeler to describe this concept, “As wheeler put it, ‘Matter tells space how to curve. Space tells matter how to move.” Our planet, our sun, our galaxy, and everything in the universe is interacting with spacetime which is everywhere and all around us. As matter interacts with what appears to be empty space it actually distorts that space, because that space is more than emptiness. Light, energy, and matter are all influenced by spacetime which itself is simultaneously shaped by the matter and energy flowing through it. Even more bizarre, across spacetime, particles seem to pop in and out of existence continuously, with particles and antiparticles appearing from nothing and then colliding on a sub-microscopic level to vanish back into nothingness.
Early on what Gefter demonstrated with the help of Einstein, Wheeler, and spacetime, is that our concrete understanding and experience of reality is not as concrete as it appears. We can only see, measure, and experience so much, and there is far more in the universe than what we currently know and understand. The ultimate reality of the universe is beyond our current comprehension, and what this reminds us is that we should not be too sure of our own knowledge, for we are always limited by what we can experience and observe from our perspective. The universe is more than the stories we tell ourselves about it.