Celebrating Einstein Through 100 Years Of General Relativity
Courtesy of Christopher O'Leary
Inside Science Minds presents an ongoing series of guest columnists and personal perspectives presented by scientists, engineers, mathematicians, and others in the science community showcasing some of the most interesting ideas in science today. The opinions contained in this piece are those of the authors and do not necessarily reflect those of Inside Science nor the American Institute of Physics and its Member Societies.
By Joey Shapiro Key and Nicolas Yunes, Guest Columnists
(Inside Science Minds) -- Albert Einstein is probably the most well-known scientific genius. His creative ability allowed him to dream of new physics and create scientific revolutions, including his masterpiece, the theory of general relativity. While people around the globe instantly recognize Einstein's image, many in the public still have not had an occasion to learn some of the astonishing details and amazing implications of his most monumental discovery.
Today, a window of opportunity is beginning to open for those of us in the physics community who wish to communicate Einstein's vision to the public. Two years from now, in 2015, we will mark the 100th anniversary of the year Einstein discovered general relativity. The Celebrating Einstein event, launched in anticipation of the centennial, tells the story of Einstein to the world and shares the excitement of Einstein's theory. To organize the project, we're working with artists, musicians, composers, scientists, dancers, filmmakers, historians, architects and educators on a series of interconnected events designed to engage the general public. Celebrating Einstein begins in 2013 with a series of free public events in Bozeman, Mont., but everyone in the world—including you—can join the celebration.
General relativity is the prevailing, modern theory of gravity. It describes the motion of all large-scale objects, including stars, planets, and galaxies. Sir Isaac Newton described gravity as an instantaneous and invisible force between two objects. His laws of motion and universal gravitation are still relevant today because objects still obey these laws approximately in everyday human experience. But Newton's laws are inaccurate when describing the gravity produced by very massive objects, such as black holes or neutron stars.
Einstein devised a completely new description of gravity. First, he realized that objects in the universe exist in three dimensions of space and one of time. He then combined these into a four-dimensional spacetime. The motion of an object throughout its entire history in the universe could then be fully described by its trajectory in spacetime. A four-dimensional spacetime is challenging for all of us to imagine, so to further continue this explanation, let's simplify spacetime as a flat canvas on which all matter lies.
Just as a bowling ball dents a canvas, a massive object such as the sun significantly bends spacetime in the solar system. As Einstein showed, relatively small objects, such as planets and comets, moving in the curved spacetime of a much more massive object, like the sun, will be deflected into curved paths, instead of traveling on straight lines. This is not because of an invisible force that pulls the small objects toward the massive one, but because the latter is curving the fabric of spacetime on which the small objects must move. In this sense, mass tells spacetime how to bend and spacetime tells mass how to move.
In a famous thought experiment, Einstein imagined a person in a windowless elevator on Earth's surface, and another person in a similar elevator but in space, far from Earth and accelerating at the same rate as that due to Earth's gravity. We all experience acceleration on elevators; we feel the floor pressing upward on our feet when an elevator starts to move upward. Einstein realized that there is no experiment that either person could conduct to distinguish between gravity's pull and this kind of acceleration, and so no fundamental difference existed. He therefore promoted the equivalence of gravity and acceleration to a general principle that gravity had to obey.
Coincidentally, as we approach the centennial of the discovery of the theory of general relativity, physicists are on the verge of directly confirming Einstein's final untested prediction in this theory: any accelerating mass produces gravitational waves, ripples in the fabric of spacetime. In Einstein's theory, these ripples would travel at the speed of light, essentially undisturbed and carrying invaluable information about the celestial objects that created them.
Astrophysicists already have indirect evidence for the existence of gravitational waves. In 1993, Russell Hulse and Joseph Taylor were awarded the Nobel Prize in physics for such an indirect detection through their observations of a binary pulsar, a pair of neutron stars going around each other, and emitting precisely timed electromagnetic waves. They observed that the binary's orbit was losing gravitational energy at exactly the rate predicted by Einstein if gravitational waves were carrying energy away from the binary system.
But the direct detection of gravitational waves is another story. Such an experiment is incredibly hard because these elusive gravitational waves are predicted to be very faint--too tiny for all but the most recently developed instruments to detect--even for the strongest waves generated in the collisions of the most massive objects in the universe. The precision required by these detectors is equivalent to measuring distances to as small as one thousandth the size of a proton.
Located in Hanford, Wash., and Livingston, La., the Advanced LIGO twin facilities -- along with a worldwide network of detectors -- are expected to make the first direct detections in the coming years, consequently ushering in a new era of astrophysics. If all goes as expected, these new gravitational-wave observations will allow researchers to directly detect the merger of two black holes and the collisions of neutron stars.
Celebrating Einstein strives to communicate all of this beauty and excitement to the general public by bridging the gap between the sciences and the arts in both its design and end products. This event is a truly collaborative and interdisciplinary effort between the departments of physics, history, communication, music, film, photography, art, and architecture at Montana State University, Princeton University, and UCLA. These many different fields all use creativity to invent new ideas that deepen our understanding of the world. Einstein's iconic figure, the centennial of the discovery of his most important theory, and the imminent direct detection of his final prediction produce a perfect theme for Celebrating Einstein.
Celebrating Einstein includes several events: a public lecture series by world-renowned scientists, including University of Maryland's Jim Gates, recipient of the National Medal of Science and member of the President's Science Advisory Panel, and David Kaiser, a best-selling author and the head of the MIT Program in Science, Technology and Society; Celebrating Einstein in the Schools, a collection of K-12 classroom lessons and activities; the Black (W)hole art installation, featuring visualizations and sounds of a small black hole spiraling violently into a supermassive one; and the Shout Across Time live multimedia theatre show, which will feature a dance-company performance illustrating a lecture on general relativity, a live orchestra, playing an original composition inspired by gravitational waves, and an original film featuring numerical simulations of black hole collisions.
Nearly 100 years after his masterwork, Einstein continues to inspire younger generations of scientists, philosophers and artists, as they strive to answer the big questions about our place in the cosmos. Celebrating Einstein draws on the power of Einstein and his ideas to tell the exciting story of gravitational-wave astrophysics through art, to bring cutting-edge physics to the public, to inspire younger generations to dare to dream about exploration, to dare to join in the most daunting quest of all: to unravel the mysteries of the universe.
Celebrating Einstein is an idea to be replicated nationally and internationally. After the events in Bozeman, which conclude in April 2013, our website will contain video, scripts, music scores, and other material from the festivities. Other locations and individuals—including you—can use these resources to host your own events. Celebrating Einstein provides a possible model, not only for general relativity outreach, but also for commemorating future scientific milestones in a truly collaborative and multidisciplinary fashion, to celebrate the ultimate in human potential through art and science.
Joey Shapiro Key, co-organizer of Celebrating Einstein, is an education specialist at the Montana Space Grant Consortium. Her Physics Ph.D. focused on Einstein's theory of general relativity. She has traveled across Montana to give presentations about gravitational-wave astrophysics, both as a physics graduate student and a NASA Student Ambassador.
Nicolas Yunes, project organizer of Celebrating Einstein, is an Assistant Professor of Physics at Montana State University in Bozeman and member of the executive committee of the NSF's Topical Group in Gravitation. He is well-known internationally, with over 80 publications on general relativity, black holes and gravitational waves. He has received several awards, including the Jürgen Ehlers Thesis Prize of the International Society of General Relativity and Gravitation and NASA Einstein Fellowship.
The authors would like to thank the sponsors that have made the Celebrating Einstein events possible.