Scientists are sure how it works since the so-called EmDrive defies all known laws of physics
The ‘impossible’ fuel-free engine called EmDrive could transport astronauts to Mars in just 10 weeks has been proven to work, even though no one known how or why it works. The revolutionary engine creates thrust by bouncing microwaves in a closed chamber and is powered only by solar energy.
While researchers have pointed out the engine is an impossible concept since it defies all known laws of physics, the engine has turned out to be a feasible option for future spacecraft.
Now, scientists have come up with a theory that could explain how it can actually work. In the next coming months, the engine will undergo peer review as scientists hope it can become a reality shortly.
The idea, however, isn’t new. The concept was proposed for the first time 16 years go when researcher Roger Shawyer came up with the incredible idea. Since 2000, four independent research facilities including one belonging to the National Aeronautics and Space Administration have recreated the drive and even though it creates thrust, no one has been able to explain how. The EmDrive converts electrical energy into thrust without the necessity for rocket fuel. Classical physics suggest that this engine should not work since it appears to violate the law of conservation of momentum.
According to the law, the momentum of a system is constant if there are no external forces acting on the system –because of this, propellant is used in traditional rockets.
However, Dr. Mike McCulloch of Plymouth University firmly believes he might have figured out the impossible drive, and his explanation is based on a new theory of inertia, describing the resistance of massive objects to changes in motion and acceleration.
The idea as to why inertia exists at all has puzzled researchers for centuries.
Dr. McCulloch proposes that inertia can be explained from an effect predicted by Einstein’s theory of general relativity called ‘Unruh radiation.’ This effect states that if there is an acceleration in a vacuum, empty space will contain gas particles at a temperature which is proportional to that of the acceleration, meaning that that universe basically heats up objects as the accelerate.
Dr. McCulloch suggests that inertia can be defined as the pressure exerted by the Unruh radiation on an accelerating body. Size matters, this is why when accelerations involved are smaller, like the case of the EmDrive, the wavelength of Unruh radiation gets larger. At extremely low accelerations, wavelengths become simply put, too large to fit into the observable universe. Researchers suggest that as a result, inertia may only take on whole-wavelength units over time, causing it to become ‘quantized.’
Researchers have discovered that at extremely low accelerations, inertia jumps unexpectedly in value, an effect already observed by scientists previously when spacecraft perform a flyby of Earth, causing them to move much faster that what scientists calculated they should.
However, we could be looking at the same thing in the EmDrive by reducing the size of allowed wavelengths of Unruh radiation.
According to a report by MIT, the cone allows Unruh radiation of a certain size at the large end but only a smaller wavelength at the other end. The inertia of photons inside the cavity changes as these bounce back and forth. In order to conserve momentum, they are forced to generate thrust.
McCulloch says there is some evidence that exactly this happens. ‘This thrust reversal may have been seen in recent Nasa experiments,’ he says.
The next step is to test out the EmDrive on a larger scale, and if it works, it could carry both passengers and equipment to the moon in just four hours, or take them to the red planet in just ten weeks. The EmDrive will be a huge thing if it works on a larger scale since it would make it possible for humans to travel outside our solar system. Fro example, a trip to Alpha Centauri would take tens of thousands of years with our current technology, however, using the EmDrive engine, a trip to Alpha Centauri would take just 100 years.
Featured Image Credit: StarTrek Movie