Refrigerators are like rockets, right?

[Antiphon]

It can be. It's just not very efficient propulsion.

Maybe a flashlight is like a roman candle.

 

[russ_watters]

If radiation/light/infrared has momentum, why can't it be a source of propulsion without ejecting any kind of particle matter?

It can be - it just doesn't provide very much (as I discussed earlier).

 

[brainstorm]

It can be. It's just not very efficient propulsion.

Maybe a flashlight is like a roman candle.

Maybe a roman candle is like a sparkler scaring away fireflies. These absurd analogies are fun. I think a whole section of the forum should be devoted to them. It would be like youtube without the videos.

 

[DaveC426913]

Maybe a flashlight is like a roman candle.

It is. In principle.

 

[brainstorm]

It is. In principle.

Why, because they both send out discrete packages of luminosity that require chemical propellant to achieve subsonic velocity and then fade away after @50ft?

Or because they're both cylindrical and produce illumination?

 

[DaveC426913]

Why, because they both send out discrete packages of luminosity that require chemical propellant to achieve subsonic velocity and then fade away after @50ft?

Or because they're both cylindrical and produce illumination?

Because both produce thrust.

 

[brainstorm]

Because both produce thrust.

Ok, let's assume you were trying to come up with a propulsion system that uses EM radiation. Obviously you want it as efficient as possible in terms of unit energy to unit propulsion. What would the variable parameters be for waste? Would there be certain wavelengths that would generate more thrust than others?

 

[DaveC426913]

Ok, let's assume you were trying to come up with a propulsion system that uses EM radiation. Obviously you want it as efficient as possible in terms of unit energy to unit propulsion. What would the variable parameters be for waste? Would there be certain wavelengths that would generate more thrust than others?

My post 34 consists of exactly 4 words. Of those 4 words, it seems I have the need to repeat two of them:

In principle.