frame-dragging which might be measured experimentally, saying:"In Einstein's General Theory of Relativity, both matter and energy can create a gravitational field. This means that the energy of a light beam can produce a gravitational field. My current research considers both the weak and strong gravitational fields produced by a single continuously circulating unidirectional beam of light. In the weak gravitational field of an unidirectional ring laser, it is predicted that a spinning neutral particle, when placed in the ring, is dragged around by the resulting gravitational field."In a later paper, Mallett argued that at sufficient energies, the circulating laser might produce not just frame-dragging but also closed timelike curves (CTC), allowing time travel into the past:For the strong gravitational field of a circulating cylinder of light, I have found new exact solutions of the Einstein field equations for the exterior and interior gravitational fields of the light cylinder. The exterior gravitational field is shown to contain closed timelike lines.The presence of closed timelike lines indicates the possibility of time travel into the past. This creates the foundation for a time machine based on a circulating cylinder of light.Funding for his program, now known as the Space-time Twisting by Light (STL) project, is progressing. Full details on the project, Mallett's theories, a list of upcoming public lectures and links to popular articles on his work can be found at the Mallett's faculty web page, and an illustration showing the concept on which Mallett has designed the time machine can be seen here. Mallett also wrote a book entitled, Time Traveler: A Scientist's Personal Mission to Make Time Travel a Reality, co-written with author Bruce Henderson, that was first published in 2006. In June 2008, motion picture director Spike Lee's production company announced it had acquired the film rights to Mallett's book. Lee is co-writing the movie script and directing the picture. In 2006, Mallett declared that time travel into the past would be possible in the 21st century and possibly within a decade. Mallett used general relativity to attempt to substantiate his claims. He created a prototype illustrating how lasers could be used to create a circulating beam of light that twists space and time, and has an equation which he claimed supports his theory. Criticism of time-travel research In a paper by Ken Olum and Allen Everett, the authors claimed to have found problems with Mallett's analysis. One of their