In 2015, two detectors from the Laser Interferometer Gravitational-Wave Observatory (LIGO) identified the first gravitational-wave signal, which was produced approximately one billion years ago during a collision of two black holes.
In addition to confirming Einstein’s Theory of General Relativity, this monumental discovery demonstrated that scientists now had an innovative new way to observe the universe. While traditional telescopes observe by using electromagnetic waves (light), LIGO observes by measuring tiny ripples in space-time* which are produced by the acceleration of massive objects moving near the speed of light.
Since that initial detection in 2015, other black hole mergers have been observed, providing unprecedented insight into these signals—their formation and evolution—but nothing as significant as what was observed in late 2017, when the LIGO team, along with their collaborators at VIRGO (a gravitational-wave observing station in Italy), detected for the first time, gravitational waves produced from two colliding neutron stars.
More remarkable still, the teams were able to pinpoint the precise locations of the stars in order to watch the event unfold. When neutron stars (the most dense known stars) collide, they produce gravitational waves and a strong burst of electromagnetic radiation known as gamma-ray burst. In this case, both the gravitational wave and the gamma-ray burst observed, reached the Earth within two seconds of each other, and this, after having traveled the universe for more than 120 million years.
As one periodical put it, “These scientists were able to witness, directly, the alchemy of the universe in action.” [Vox, 10/16/2017]
In the hours and days that followed the detection, scientists studied all bands of the electromagnetic spectrum: radio, infrared, X-ray, and others. “Together,” says Professor Vuk Mandic, a member of the LIGO team, “these observations have enabled a series of new studies, including a novel measurement of the expansion of the universe and a study of the formation of the heaviest elements (such as platinum and gold) in the mergers of neutron stars.”
Join us March 1 when Mandic will detail how the observation of gravitational waves helped lead to the origin of gold, but more, to a golden new age in learning about the universe.
*In physics, space-time is a system of one temporal and three spatial coordinates by which any physical object or event can be located. This is also called the space-time continuum.
Vuk Mandic, PhD, University of California, Berkeley, is a Professor of Physics in the Minnesota Institute for Astrophysics, School of Physics and Astronomy, at the University of Minnesota, where his research focuses on the physics of the earliest stages and highest energies of the Universe. His primary experiments are in the areas of gravitational waves and dark matter. Within the gravitational wave field, he is interested in detecting potential signals emitted in the very early universe (a fraction of a second after the Big Bang). Within the dark matter field, he works as a member of the Super CDMS (Cryogenic Dark Matter Search) Collaboration, which aims to detect dark matter in the form of weakly interacting massive particles, as well as a member of the MINER Collaboration, which aims to measure the scattering of neutrino particles off nuclei. Mandic is a member of the renowned LIGO Scientific Collaboration, which received the 2016 Breakthrough Prize in Fundamental Physics and the 2016 Gruber Cosmology Prize. The University has honored Mandic with a McKnight Professorship (2010−2012) and the Taylor Research Prize (2017). He is a member of the American Astronomical Society and the International Astronomical Union, and a Fellow of the American Physical Society.
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