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Goddard Space Flight Center Engineering Colloquium

Date: Monday, April 28, 2003

Speaker: Robert Ehrlich

Title: Faster-than-Light Speeds and Tachyons: An Overview with Demonstrations


In his 1905 theory of Special Relativity, Albert Einstein concluded that "speeds in excess of light have no possibility of existence." Indeed, the universal speed limit c = 3 x 10^8 m/s appears to be built in to the equations of relativity, because an infinite amount of energy would be required to bring an object having speed less than c to a faster-than-light (FTL) speed. Despite Einstein's claim about the impossibility of FTL speeds, forty years ago George Sudarshan and two coworkers described a way FTL speeds might be formally consistent with the equations of relativity. Hypothetical FTL particles, known as tachyons, have been searched for over the last 40 years, but nothing conclusive has been found. Nevertheless, there are hints that tachyons may exist, and some researchers in string theory and cosmology have a new interest in such objects as a way of explaining cosmic inflation and dark energy. This talk presents an up-to-date overview of tachyons, FTL speeds, and their role in special relativity, and it includes a number of low tech demonstrations.


Robert Ehrlich is a professor of physics at George Mason University -- having joined GMU in 1976 as its chair, a position he held for 13 years. A 1964 Columbia University Ph. D., Dr. Ehrlich has also held positions at the University of Pennsylvania, Rutgers University, and the State University of New York College at New Paltz. His most recent book: "Nine Crazy Ideas in Science -- a Few Might Even Be True," was published by Princeton University Press last year. One chapter of the book deals with the subject of this talk. 

Colloquium Committee Sponsor: Jim Heaney

Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov