Does The EmDrive Really Defies Newton's Third Law?

The Em drive (electromagnetic drive ) is a radio frequency (RF) resonant cavity thruster, is a controversial proposed type of electromagnetic thruster with a microwave cavity, designed to produce force from an electromagnetic field inside the cavity. Skeptics have deemed it to be impossible.

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On November 17 last year, EmDrive (Electromagnetic drive) finally entered the hall, appeared in formal peer-reviewed journals in the form of essays, triggering a new round of concerns. However, it is too early to say that it overthrew the classical laws of physics.

NASA's Johnson Space Center has a whimsical team. Not long ago, the team made a landmark breakthrough - formally published on the experimentally proven "EmDrive" essay, which many experts have not been optimistic about before. The propeller powers spacecraft in space without the use of any fuel.

EmDrive prototype in NASA Labs.--source

The team said in the paper that the electromagnetic propulsion system transforms electrical energy into propulsion by launching the microwave back and forth within a closed cavity. In theory, this lightweight engine delivers spacecraft to Mars in 70 days.

However, the main controversy that has long been placed on this engine is that it violates the classical laws of physics - Newton's third law and conservation of momentum. So, even if EmDrive was able to work as the team said, scientists did not understand how it works. Earlier, reports on the engine were heavily questioned, and many physicists even directly denounced it as pseudoscience.

However, the new paper, which claims EmDrive's work, passed independent peer review. So, the revolution in space travel is coming? Or is this "impossible" space propeller causing just a misleading move into another astray?

What is EmDrive?

The concept of EmDrive was first proposed by British scientist Roger Shawyer 20 years ago. NASA advanced physics research laboratory (also known as Eagleworks laboratory) put it into practice, and tested.

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In short, the principle of the EmDrive developed by Eagleworks Labs is that electromagnetic energy (microwave photons) is repeatedly ejected in a cone-shaped, closed cavity to produce propulsive force. When microwave photons hit the inner wall of the cavity, they push the device forward, and the device does not spray anything outward. This is very different from the previous propeller. Some NASA spacecraft use ion thrusters to generate power by ionizing propulsion fuels (typically xenon), although they eject outwardly charged electron beams.

If EmDrive can withstand the test, it means that future spacecraft will no longer need tons of propulsion fuel. Light loading is the key to high-speed, low-cost, long-haul space travel.

EmDrive, how it violates the laws of physics?

In 1687, Newton published three laws of motion, which later became the cornerstone of classical mechanics. Over the next few centuries, Newton's three laws of motion have been verified countless times.

EmDrive and Newton's third law have irreconcilable contradictions. Newton's third law states that when two objects interact with each other, the forces applied to each other are equal in magnitude and opposite in direction. Newton's third law explains why the boat advances when people paddle - because the paddles and the water interact, the water produces opposite forces on the paddles. Newton's third law also explains why the engine produces propulsion-the engine drains the hot gas backwards to get forward propulsion.

EmDrive stress diagram. Electromagnetic waves in the vacuum cylinder ejection, the upper and lower wall to produce different sizes of force.--source

Curiously, EmDrive does not emit anything outward, making it impotent under Newton's Third Law and another law of classical mechanics - the conservation of momentum. If EmDrive does not get forward momentum by removing matter backwards, where does its power come from? It's a bit like the crew in the spacecraft pushing the spacecraft by pressing the wall, or an older joke - grabbed his hair and lifted it up.

Has anyone tested EmDrive?

In 2014, the Eagleworks lab unveiled the results of the early successful test of the EmDrive engine. Later, they tested EmDrive under more stringent conditions, including several recently published experiments.

Other researchers have also developed and tested different versions of EmDrive. For example, some researchers in Europe and China conducted relevant research (Yang Juan, Northwestern Polytechnical University, who published a similar study, see references), and even some EmDrive enthusiasts are busy developing their own research and testing Possible physics engine. However, no one can prove that their engine can operate as the theory describes it.

How Em Drive is different?

Eagleworks Labs' paper is published in the peer-reviewed journal, Journal of Propulsion and Power. Passing peer review does not guarantee that the paper's findings or observations are valid, but it demonstrates that its experimental setup, results, and interpretation of results are endorsed by some independent scientists.

This essay describes the testing of EmDrive with testing near vacuum (similar to space). They placed the engine on a device called a twist, started the engine, and then deduced the amount of propulsion from the distance it operated. They estimate that the EmDrive can generate 1.2 milli-bump per kilowatt of power.

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Compared with the traditional engine, this push is nothing. But this is achieved without any fuel, so it can not be said to be insignificant. In technologies that are also not fuel-driven, solar sail and other technologies that rely on photon propulsion produce only a few hundredths of its propulsion at between 3.33 and 6.67 micro-Newtons per kilowatt.

Another criticism of EmDrive is that it warms up after it starts, and some people think it is using it to heat the surrounding air for propulsion. However, testing in a vacuum environment dismisses this concern. Of course, EmDrive faces more problems than this.

First of all, we do not know whether EmDrive really can produce propulsion, we need further confirmation on this point. However, a number of assumptions have been made that explain its operational logic.

Eagleworks Labs believes that microwave photons are driving the "quantum vacuum virtual plasma," a tumbling sea of ​​particles that continually emerge and disappear at the quantum level. Sean Carroll, a physicist at the California Institute of Technology, said the problem is that there is no evidence that "quantum vacuum virtual plasma" exists. He believes there is a quantum vacuum, but it does not produce a plasma that can be propelled.

In the paper, the Eagleworks lab team cites so-called "pilot-wave theory" to describe the process by which quantum vacuum produces propulsion. However, they also admit that the theory "is not the mainstream view of physics."

Mike McCulloch, a physicist at the University of Plymouth in the UK, argues that EmDrive has demonstrated a new theory of inertia that involves Unruh radiation (an accelerated observer can observe that observers in an inertial frame of reference can not see To blackbody radiation). According to him, because EmDrive's cones have different top and bottom ounce luminescence wavelengths, their inertia changes as the photons in the cavity come and go, causing propulsive forces when the momentum is conserved.

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Rochester Institute of Technology physicist Brian Koberlein said that although McCulloch believes that the existence of ominous radiation, but this phenomenon has not been experimentally confirmed. The theory also states that the speed of light inside the EmDrive cavity will change, contrary to Einstein's special theory of relativity.

However, part of the energy generated as the object accelerates may be stored in this object. Simply put, here involves the interaction of gravitational and transient inertial mass fluctuations. Jim Woodward believes this explains why EmDrive moves without violating momentum conservation. The Mach effect proposed by Woodward in 1990 relates to this.

EmDrive will not be a nonsense?

Of course, EmDrive may be nonsense. There have been many examples in history, such as "neutrinos that are faster than the speed of light" that eventually proved to be the erroneous results of bad experiments.

In this paper, the authors discuss nine sources of possible experimental errors, including air flow fluctuations, electromagnetic radiation leakage, and magnetic interactions. These errors can not be completely ruled out, need more experiments to further prove.

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