ver since the EM drive first made headlines, science lovers have puzzled over how the propulsion system seems to produce thrust, despite the fact it's 'impossible' according to one of the most fundamental laws of physics - Newton's third law of motion.
Now a team of physicists have put forward an alternative explanation - it turns out the EM drive could actually work without breaking any scientific laws, if we factor in a weird and often overlooked idea in quantum physics - pilot wave theory.
For those who need a refresher, the crux of the problem here is that the EM, or electromagnetic, drive appears to produce thrust without any fuel or propellant.
That's awesome because it means we can get to space with way less pay load - it's proposed it could even get us to Mars within 72 days.
But it's also perplexing, because, according to Newton's third law, every action must have an equal and opposite reaction. So without pushing any propellant out one end, the drive shouldn't be able to produce thrust in the opposite direction.
Still, as a NASA peer-reviewed paper showed last year, the drive does produce thrust, at least as far as we can currently tell. And a relatively large amount of thrust at that. We just don't know how.
So either our understanding of physics isn't right, or we're missing a big piece of the puzzle when it comes to the EM drive.
A new paper published in The Journal of Applied Physical Science International makes the argument that what we're missing is pilot wave theory - a slightly controversial alternative interpretation of quantum mechanics.
Researchers José Croca and Paulo Castro from the Centre for Philosophy of Sciences of the University of Lisbon in Portugal suggest that not only could pilot wave theory explain the mysterious behaviour of the EM drive, it could help to make it even more powerful.
"We have found that applying a pilot wave theory to NASA's EM drive frustum [or cone], we could explain its thrust without involving any external action applied to the system, as Newton's third law would require," Castro told ScienceAlert via email.
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