On Mon, Nov 21, 2016 at 10:48:57PM +0000, Timothy Collinson wrote:
> Was Marc Miller more prescient than we give him credit for in m-drives?
>
> Or is this going to turn out to be another disappointment when reality
> hits?!

Probably the latter, but I'm still hopeful.

> Even NASA doesn't know how it works. NASA scientists have determined
> that an ‘impossible’ engine that could take us to Mars in just 10
> weeks does actually work, despite needing no fuel to operate it.

They haven't confirmed that it works.  They've confirmed that torque
measurements they took in a very delicate ground-based apparatus were
nonzero, though much smaller than everyone else who claims to have
tested this type of device.

That latter property is already a bit of a danger sign: in the history
of science, effects that get smaller when tested in more carefully
controlled conditions usually mean that the results are due to
problems in the experimental setup, and not to some previously unknown
new laws of physics.

Their previously experiment had the seriously flaw that they were
testing in air, which introduced many possible sources of torque
including simple convection airflow.  The new paper presents the
results of testing in vacuum, though still with much the same type of
complicated torque balance.

They still caution that they know of at least two possible sources of
experimental error that they haven't yet ruled out, and articles
elsewhere list another half dozen or so.  They do plan to test the
device in orbit at some later stage, which would rule out most of
those sources of error.  Obviously launching and testing in space is
quite a lot more expensive than in a lab, so trying to rule out any
effect on the ground was a prudent first move.  After that, they would
need to test in a wider variety of conditions to rule out other
possibilities such as local interaction with Earth's magnetic field.

There is still quite some way to go before they can proclaim that it
works as a space drive.

- Tim