On 17/02/2021 11:16, Jethro_uk wrote:
On Wed, 17 Feb 2021 11:11:22 +0000, Tim Streater wrote:

On 17 Feb 2021 at 10:48:40 GMT, Jethro_uk
wrote:

On Wed, 17 Feb 2021 08:12:16 +0000, jon wrote:

New type of engine using arbitrary waveform drive for producing
forward motion.....experimental or is it just mental ?

Very first thought was "Em-Drive"

https://en.wikipedia.org/wiki/EmDrive

Looking at that, not sure why both ends have a hole. Send all the
microwave radiation out of one end and you should get a thrust. See:

https://en.wikipedia.org/wiki/Pioneer_anomaly

Read the third para about what is generally accepted as the explanantion
for the anomaly - namely that the spacecraft is emitting thermal
radiation more in one direction than another.

Of course, the thrust is miniscule.

When you emit radiation like that you should get a thrust as you are
sending out photons, which equtes to mass according to Albert.

There was a brief suggestion - presumably debunked - that the energy was
subtly changing the space-time in the cavity and shifting the centre of
gravity ever so slightly to create thrust.

I am nowhere near well versed enough in the physics to know if that's
even worthy of consideration, but energy has to go somewhere. If not into
moving the thing then at least warming it up.

I wonder what the possibilities are of getting to build some sort of base
on one side of an asteroid, and fire fusion bombs on the other to create
thrust. (Anyone remember Space 1999 ?)

Many years ago one of the well known science fiction writers (I can't
recall which) wrote a story involving large "rockets" with massively
thick bases, powered by repeatedly dropping and detonating atom bombs
under the bases.