Move over, Newton! New engine appears to defy laws of physics
"Regardless of whether or not there is a sensible explanation, more important is simply: does it actually work?" Hywel Owen, University of Manchester
BRITAIN: The EmDrive is quite literally enough to send Isaac Newton spinning in his grave, albeit at a very gentle rate.
An engine invented by a British engineer 16 years ago that appears to break at least one fundamental law of physics has been tested and found to work by scientists at Nasa.
The device, which is said to produce thrust without propellant, would be one of the most remarkable advances in the history of science, not only enabling interstellar travel within a single human lifespan but also ripping up two centuries’ worth of textbooks.
Up to now the drive has, to put it politely, languished in the outer darkness some distance beyond the frontiers of mainstream research.
Over the weekend, however, researchers at Nasa’s Advanced Propulsion Physics Laboratory in Houston, Texas - better known as the Eagleworks - released a longheralded paper suggesting that the drive might just work. This leaves two possibilities. Either Nasa and its independent reviewers got something wrong, or physics has some serious catching up to do.
Just after the turn of the millennium Roger Shawyer, an English aerospace engineer, released the blueprints for a lopsided box something like a microwave that would trundle along purely under the power of the electromagnetic waves bouncing around inside it.
How exactly this would work has remained a mystery. Newton’s third law of motion says ‘‘to every action there is always opposed an equal reaction’’ so the box should not be able to move without pushing something back.
Nevertheless, researchers at the Eagleworks tested a prototype similar to Shawyer’s EmDrive in a vacuum last year.
Their study, published in the Journal of Propulsion and Power, shows that it does indeed appear to produce 1.2 millinewtons per kWh of thrust. This means, essentially, that if you were to feed it enough energy to power an electric shower for 30 seconds, you would get a push equivalent to the weight of a single drop of water.
British scientists, however, were less convinced. Hywel Owen, lecturer in accelerator physics at the University of Manchester, said that the effect the Nasa experiment had identified was so tiny that it could easily have arisen from a mistake in the set-up.
‘‘Regardless of whether or not there is a sensible explanation, more important is simply: does it actually work?’’ he said.
If the finding does turn out to be real, how do scientists go about explaining a box that can move by itself?
The Nasa researchers suggest that perhaps both Newton and Shawyer were right: the EmDrive is pushing back on something in empty space due to an obscure byroad of quantum mechanics where even the nothingness of a vacuum is not quite nothing.
Conclusive evidence may be around soon enough. In September Guido Fetta, an American chemical engineer, announced plans to test his own version, dubbed the Cannae drive after a quote from Star Trek that ‘‘ye cannae change the laws of physics’’, on a small satellite orbiting the Earth next year. - The Times