The EM drive is controversial in that it appears to violate conventional physics and the law of conservation of momentum; the engine, invented by British scientist Roger Sawyer, converts electric power to thrust without the need for any propellant by bouncing microwaves within a closed container. So, with no expulsion of propellant, there’s nothing to balance the change in the spacecraft’s momentum during acceleration. Hence the skepticism. But as stated by NASA Eagleworks scientist Harold White:

[T]he EM Drive’s thrust was due to the Quantum Vacuum (the quantum state with the lowest possible energy) behaving like propellant ions behave in a MagnetoHydroDynamics drive (a method electrifying propellant and then directing it with magnetic fields to push a spacecraft in the opposite direction) for spacecraft propulsion.

The story begins several years back with a British inventor named Roger Shawyer and his EmDrive, a prototype rocket engine which he claimed generated thrust by bouncing microwaves around in an enclosed metal funnel. Since no mass or energy emerged from the engine, Shawyer’s claim was another way of saying that he’d found a way to violate the conservation of momentum. In Baez’s words, “this is about as plausible as powering a spaceship by having the crew push on it from the inside.” Shawyer argued that he was exploiting a loophole within general relativity. Baez calls his explanation “mumbo jumbo.”

campermon wrote:Awesome!

I hear that he's working on a hesienberg compensator at the moment.

twistor59 wrote:

campermon wrote:Awesome!

I hear that he's working on a hesienberg compensator at the moment.

You can get them from China off ebay

Made of Stars wrote:Nerds.

campermon wrote:

Made of Stars wrote:Nerds.

And proud!

Made of Stars wrote:

campermon wrote:

Made of Stars wrote:Nerds.

And proud!

Speaking of nerds: I took my son to get his eyes checked yesterday, and he's getting new glasses. The first set of frames made him look like Joe 90.

Back to improbability drives - there's another thread about Emdrive kicking around somewhere. Some mod should get onto that.

twistor59 wrote:Maybe it should be in pseudoscience. I only posted in physics because it had John Baez and Sean Carroll in my link, although they're both there saying it's bollocks!