‘Impossible’ EmDrive could prove Newton wrong

Shaw thing: Inventor Roger Shawyer and the EmDrive. (See the video in Become An Expert.)

It is the most fabled law of physics: ‘For every action, there is an equal and opposite reaction.’ But now NASA says that an invention, once mocked by scientists, could prove Newton wrong.

For years, the EmDrive was dismissed as an ‘impossible’ machine invented by a delusional aerospace engineer. It was the butt of jokes in the scientific community. But this weekend, a ‘maverick research team’ at NASA published an astonishing report. They had tested the machine themselves in Texas — and it worked.

Its inventor Roger Shawyer is delighted. For over a decade, he has said that it could lead to flying cars, speedy interstellar travel, even a solution to climate change.

These are bold claims for something which looks like a tin bucket. In fact, it is a ‘propellantless propulsion system’: an engine which moves without exerting force on the world around it.

Isaac Newton’s third law of motion says that objects move by interacting with other objects. Think of how a car’s wheels roll back against the road, or how a rocket takes off when its engines fire towards the ground.

But the EmDrive does not do anything like that. Instead it uses electricity to produce microwaves which bounce around its insides. Under the right conditions, Shawyer says this creates a small amount of thrust which moves the machine forwards. It is not by much — imagine someone moving a car by pushing very hard on the steering wheel from the driver’s seat. But Shawyer insists that it works. And now NASA says that he may be right.

There’s just one problem: that should be impossible. Newton’s third law has been one of the foundations of physics for more than 300 years.

For this reason, many scientists remain skeptical. One quoted the astrophysicist Carl Sagan: ‘extraordinary claims require extraordinary evidence’ — and so far the evidence is still flimsy. Another called the machine ‘baloney’, and described Shawyer’s science as ‘mumbo jumbo’.

And yet the report has reignited interest in the EmDrive. Next year Guido Fetta, an American inventor, plans to send a similar device to be tested in space. If it works, we may need to rethink everything we know about the universe.

Moving on

For some, this is a terrifying prospect. Newton’s theories were the start of modern science. Their publication was the first time that someone had used reason, mathematics and logic to explain the world around us, lifting the curtain — just a little — on the mysterious forces that govern our universe. If he was wrong, how can we trust anything at all?

Don’t panic, say others. By breaking the third law of motion, the EmDrive could be the beginning of a truly amazing future, in which we hop between planets at previously unthinkable speeds. The fact that it would make us question the laws of physics is an added bonus — after all, rethinking the world around us is part of what makes science so exciting.

You Decide

  1. If the EmDrive works, it could take you as far as Pluto in mere months. Which planet would you visit?
  2. Is it terrifying or exciting to think that 300 years of science could be wrong?


  1. Design a rocket, using the EmDrive’s technology, which can take people into space.
  2. Research Newton’s three laws of motion, then imagine they suddenly stop being true. Write three ways in which the world as we know it would be different.

Some People Say...

“Nothing in life is to be feared, it is only to be understood.”

Marie Curie

What do you think?

Q & A

I’m confused — does it really work?
We don’t know for sure. The scientists at NASA (a small team known as ‘Eagleworks’) behind the experiments found that it produced a thrust of 1.2 millinewtons per kilowatt. Although they tried to acknowledge and remove any other influences on the machine, they admitted that they could still have made an error. In other words, more research is definitely needed.
Does it really make any difference if a theory is disproved?
Disproving Newton’s theory would not suddenly mean that forces stopped having equal and opposite reactions in almost all cases. So in your day to day life, things might not change. But if it works, the EmDrive could revolutionise future technology, and lead to a much deeper understanding of the universe — which can only be a good thing.

Word Watch

Shawyer invented the machine in 1999. He argues that it does not in fact break the laws of physics, although most scientists dismiss his explanation. If it does work it would be a major breakthrough for space travel, as rockets would not need heavy fuel.
The report was published in the AIAA Journal of Propulsion and Power. It was peer reviewed, meaning other independent scientists could not find any mistakes — although that does not mean they did not happen, as the authors themselves admitted.
Interstellar travel
Travel between stars. Without worrying about fuel, a working EmDrive could use electricity (perhaps generated by solar power or a small nuclear reactor) to travel faster and more cheaply than any other spacecraft.
Climate change
A light, simple alternative to burning fossil fuels would certainly help reduce carbon emissions.
Third law of motion
Every force is met with an equal reaction in the opposite direction. This has been proved consistently since it was published in 1686.
Guido Fetta
The engineer will send his ‘Cannae Drive’ into low orbit for six months.


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