Planet cracking missiles

[Nyrath]

[1] Reactionless drives are spacecraft propulsion systems that do not use Newton's law of action and reaction, that is, they do not expend reaction mass. Just pump in electricity, and your ship accelerates. This would revolutionize spacecraft design, and open the entire solar system if not the stars.

 

[2] Reactionless drives are thought to be impossible by mainstream physicists because they violate the law of conservation of momentum

 

[3] Roger Shawyer's EmDrive is a reactionless drive. All mainstream physicists are quite sure it is bunk.

 

[4] Chinese researchers are going to try and build it anyway.

 

[5] This could lead to serious consequences if they succeed. This would give China the ability to create planet cracking missiles.

[Cancer]

Re: Planet cracking missiles

 

Actually, if the thing exhausts neutrinos (which you can't detect without extraordinary measures), it wouldn't, technically, be reactionless. I'm in no way suggesting that's what's going on here, but there is that loophole.

[Sundog]

Re: Planet cracking missiles

 

Any time the scientific community gets totally up in arms about something like this, I usually take it as an indication that more research is appropriate.

[Nyrath]

Re: Planet cracking missiles

 

Actually' date=' if the thing exhausts neutrinos (which you can't detect without extraordinary measures), it wouldn't, technically, be reactionless. I'm in no way suggesting that's what's going on here, but there is that loophole.[/quote']

True, but if you read the description of the EmDrive, it becomes clear that it is just a tired re-hash of the Dean Drive hoax.

[Nyrath]

Re: Planet cracking missiles

 

Any time the scientific community gets totally up in arms about something like this' date=' I usually take it as an indication that more research is appropriate.[/quote']

Which the Chinese are doing...

[mirage]

Re: Planet cracking missiles

 

[1] Reactionless drives are spacecraft propulsion systems that do not use Newton's law of action and reaction, that is, they do not expend reaction mass. Just pump in electricity, and your ship accelerates. This would revolutionize spacecraft design, and open the entire solar system if not the stars.

 

[2] Reactionless drives are thought to be impossible by mainstream physicists because they violate the law of conservation of momentum

 

[3] Roger Shawyer's EmDrive is a reactionless drive. All mainstream physicists are quite sure it is bunk.

 

[4] Chinese researchers are going to try and build it anyway.

 

[5] This could lead to serious consequences if they succeed. This would give China the ability to create planet cracking missiles.

 

I would be more than happy to sell them plenty of write only memory, to help protect their data.

[pinecone]

Re: Planet cracking missiles

 

It is likely bogus...but less shouting and more testing is the "scientific" way to settle such things....

[Outsider]

Re: Planet cracking missiles

 

A planet busting missile isn't all that useful when you and your potential enemies live on the same planet, of course. Not that a working (& powerful) reactionless drive wouldnt have other uses...

[pinecone]

Re: Planet cracking missiles

 

You could put a reationless drive bus in a looping patern and toss BB's at anyone who annoyed you (By say not joining your empire...) at near light speed glass beads are city killers at least....

[Cancer]

Re: Planet cracking missiles

 

Just don't miss.

[Nyrath]

Re: Planet cracking missiles

 

You could put a reationless drive bus in a looping patern and toss BB's at anyone who annoyed you (By say not joining your empire...) at near light speed glass beads are city killers at least....

Of course, by the same token, if the planet leisurely tosses a glass bead into the path of the drive bus, the bus will also experience the equivalent of a city killer nuke. It doesn't matter if you are a stationary city hit by a relativistic glass bead, or a relativistic bus that hits a stationary glass bead. The same energy will be released.

 

So the bus will have to jink around a little, to become a harder target.

 

Which is good, unstoppable weapons are boring.

 

Now, a city killer is about 25 megatons worth of "boom". Say 1.1 x 10^17 Joules of energy, refer to the boom chart.

 

For a glass bead to kill a city, it will have to be moving pretty freaking fast. About 0.9999999999 c according to my slide rule (assuming a glass bead has a mass of about 0.02 grams).

 

If the projectile was one kilogram (about two pounds), it would only have to move at 0.95 c.

 

Note that once a projectile is moving faster than 0.866 c, it does more damage than a stationary lump of pure antimatter with the same mass.

 

The flip side is that you have to spend more than that amount of energy in the drive of your bus, in order to make the projectiles relativistic. Nothing is free.

[jaws]

Re: Planet cracking missiles

 

Nyrath,

 

Don't know if i should hate or love you. You bring comprehension to us non-scientific bunch, but you really destroy the simplicity of fiction . As one reader complained on your site. I can never read sci-fi the same way again. Sure it forces authors to be more scientifically accurate. But doesn't that take away from their spell bound story weaving?

 

Ok well, innocence once lost can never be recovered. You need a major disclaimer at the beginning of your illusion destroying truth revealing website.

 

But oh well. Such is the price of knowledge and knowledge is power. SO I guess, thanks.

 

Yeah yeah yeah, spread spread... cant give it all to one genius it might go to his head.

[Nyrath]

Re: Planet cracking missiles

 

Nyrath,

 

Don't know if i should hate or love you. You bring comprehension to us non-scientific bunch, but you really destroy the simplicity of fiction . As one reader complained on your site. I can never read sci-fi the same way again. Sure it forces authors to be more scientifically accurate. But doesn't that take away from their spell bound story weaving?

Thanks! {blush}

 

I did include Tom Clark's lament that you mentioned. But maybe I should put it closer to the top of the page.

 

However, even though I take away some innocence, in return I give you the Game Master a source of all sorts of diabolical ideas to spring on your hapless players.

[jaws]

Re: Planet cracking missiles

 

Like I said.

Love... Hate... I can now take out my frustration on my players, for every sci-fi book I read from an author who though may be a great story teller, didn't do his physics homework

 

So i guess I'll just tell my players to hate you while I praise your great work.

 

[pinecone]

Re: Planet cracking missiles

 

Of course, by the same token, if the planet leisurely tosses a glass bead into the path of the drive bus, the bus will also experience the equivalent of a city killer nuke. It doesn't matter if you are a stationary city hit by a relativistic glass bead, or a relativistic bus that hits a stationary glass bead. The same energy will be released.

 

So the bus will have to jink around a little, to become a harder target.

 

Which is good, unstoppable weapons are boring.

 

Now, a city killer is about 25 megatons worth of "boom". Say 1.1 x 10^17 Joules of energy, refer to the boom chart.

 

For a glass bead to kill a city, it will have to be moving pretty freaking fast. About 0.9999999999 c according to my slide rule (assuming a glass bead has a mass of about 0.02 grams).

 

If the projectile was one kilogram (about two pounds), it would only have to move at 0.95 c.

 

Note that once a projectile is moving faster than 0.866 c, it does more damage than a stationary lump of pure antimatter with the same mass.

 

The flip side is that you have to spend more than that amount of energy in the drive of your bus, in order to make the projectiles relativistic. Nothing is free.

 

Well I figure it's easier to "stealth" a bus vs hiding a planet... Heck with a Emdrive I could use solar panels couldn't I?

 

As for "Lack of bang" just toss a handfull then, once you get up to speed, tossing junk gets easy...

[AmadanNaBriona]

Re: Planet cracking missiles

 

Well I figure it's easier to "stealth" a bus vs hiding a planet... Heck with a Emdrive I could use solar panels couldn't I?

 

As for "Lack of bang" just toss a handfull then, once you get up to speed, tossing junk gets easy...

 

OK, everybody who's read Nyrath's site, all together now....

 

a one, and a two,

and a one, two, three, four...

 

"There's no stealth in space!"

 

 

Sorry man...

Had to do it.

One of those dearly held tropes I had to let go of after reading the site.

 

 

Now I know what it's like to read one of those Mythos tomes that you can't unread

[pinecone]

Re: Planet cracking missiles

 

OK, everybody who's read Nyrath's site, all together now....

 

a one, and a two,

and a one, two, three, four...

 

"There's no stealth in space!"

 

 

Sorry man...

Had to do it.

One of those dearly held tropes I had to let go of after reading the site.

 

 

Now I know what it's like to read one of those Mythos tomes that you can't unread

 

OK, read the Blurb...an Emdrive is not a reactive motor.....and not all reactive engines are all that bright....(Say a laser...or a ion drive) so...nice shouting, but poor sciencing....

[AmadanNaBriona]

Re: Planet cracking missiles

 

OK' date=' read the Blurb...an Emdrive is not a reactive motor.....and not all reactive engines are all that bright....(Say a laser...or a ion drive) so...nice shouting, but poor sciencing....[/quote']

 

And how does one make the power for the the drive without heat?

 

 

 

 

(to be clear, I'm joshing with ya a teeny bit... I've literally spend days poring over his Atomic Rockets site.... call me one of Nyraths Disciples, spreading the word)

 

edit: linky

[Nyrath]

Re: Planet cracking missiles

 

OK' date=' read the Blurb...an Emdrive is not a reactive motor.....and not all reactive engines are all that bright....(Say a laser...or a ion drive) so...nice shouting, but poor sciencing....[/quote']

Ah, I suppose that in direct violation of the second law of Thermodynamics, the Emdrive is 100% efficient in converting electricity into thrust, without a single watt being lost as waste heat?

 

And where, exactly, is the electricity for the Emdrive coming from?

 

Yes, not all reactive engines are all that bright. An ion drive can only be detected if it is closer than 93 million miles! This is approximately the distance between the Earth and the Sun.

 

The Space Shuttle's main engines can be detected as far away as Pluto's orbit. The Space Shuttle's manoeuvering thrusters could be seen as far as the asteroid belt.

 

There ain't no stealth in space.

[Cancer]

Re: Planet cracking missiles

 

Yes' date=' not all reactive engines are all that bright. An ion drive can only be detected if it is closer than [b']93 million miles![/b] This is approximately the distance between the Earth and the Sun.

 

The Space Shuttle's main engines can be detected as far away as Pluto's orbit. The Space Shuttle's manoeuvering thrusters could be seen as far as the asteroid belt.

 

There ain't no stealth in space.

 

And "concrete" design concepts for antimatter rockets -- presumably on interstellar ships --- can be seen and identified hundreds of parsecs away.

[pinecone]

Re: Planet cracking missiles

 

Yes all true...big energetic plumes are easy to see....but a infrared source Can be hidden with a heat sink (for while any way) and if that ion drive is facing away from you? 93 million miles?

 

Why are we all worried about detecting astoroids when everthing is so easy to see?

 

If someone is tossing photons out the back as a laser....how does anyone see it if they are not in the spread?

[L. Marcus]

Re: Planet cracking missiles

 

It's the problem with heat pumps -- it takes energy to direct those exhaust photons, and that energy will produce even more waste heat that will have to be redirected . . .

 

It's a vicious circle. You'd just end up with a ship built around a giant cooling system.

[Nyrath]

Re: Planet cracking missiles

 

Short answer: read the link

http://www.projectrho.com/rocket/rocket3w.html#nostealth

 

Yes all true...big energetic plumes are easy to see....but a infrared source Can be hidden with a heat sink (for while any way) and if that ion drive is facing away from you? 93 million miles?

An infrared source can be hidden with a heat sink, for about five minutes. Unless your heat sink is several miles in diameter.

 

Yes, an ion drive can be detected at a range of one astronomical unit, even if the drive is facing away from you. And this is only if the drive is throttled down to less than 1/1000 of a g of acceleration. If the acceleration is higher, the detection range grows.

 

The direction of the drive makes little difference. And even if it did, what use is it to only be able to accelerate directly at you? Unless you were trying to ram?

 

And the phrase "facing away from you" contains two assumptions:

[1] the ion drive owner knows where "you" are located

[2] "you" are the only observer in the solar system. If "you" deployed a few observational space probes around a few other planets, it will be impossible for the ion drive to face away from all of them.

 

And then there is the problem that an ion drive requires lots of electrical power to operate. Which requires a power plant of some kind, or a huge solar array. All of which will generate waste heat as it converts fuel or solar energy into electricity. Which will give away the ion drive's position.

 

You don't seem to understand that the background of space is at three degrees above absolute zero, so almost anything else stands out like a spotlight.

 

Why are we all worried about detecting astoroids when everthing is so easy to see?

We are not worrying that asteroids are hard to see. We are worrying that nobody is willing to fund a constant sky watch to detect dangerous asteroids.

 

If someone is tossing photons out the back as a laser....how does anyone see it if they are not in the spread?

 

[1] How can the laser user be sure they know where all the observational space probes are?

[2] A laser used as a photon drive requires about THREE HUNDRED MEGAWATTS to produce one measly Newton of thrust.

 

The three engines on the Space Shuttle produce a combined 5.37 million Newtons of thrust.

 

To produce this much thrust with a laser would require 1.6 petawatts (1,611,000,000,000,000 watts).

 

Lasers are notoriously inefficient. Most have efficiencies of about 25%. Say we have a free-electron laser which has a theoretical maximum efficiency of 65%. This means that 35% of the input energy becomes waste heat.

 

This means that if the laser energy is 1.6 petawatts, the waste heat will be 860 terawatts. This means that the laser will be creating waste heat at a power level of 300 times the yearly energy consumption of the United States each second.

 

And you are somehow going to hide all this waste heat?

 

Again, read the link. Chances are, whatever you try to come up with has been tried already.

 

Of course if in your role as a Game Master, you invent an exciting campaign for your players that depends upon magically creating stealth in space, then you can ignore scientific accuracy in the name of pleasing your players.

[Kristopher]

Re: Planet cracking missiles

 

It strikes me as quite useful to the author if he simply supposes a system, built of handwavium, that performs an end-run around the 2nd law of thermodynamics. Such as, say, a system which converts heat above a certain threshold temperature into electical power, at a rate greater than it generates waste heat.

[Nyrath]

Re: Planet cracking missiles

 

It strikes me as quite useful to the author if he simply supposes a system' date=' built of handwavium, that performs an end-run around the 2nd law of thermodynamics. Such as, say, a system which converts heat above a certain threshold temperature into electical power, at a rate greater than it generates waste heat.[/quote']

 

{shudder}

 

Ummmmmm, I have a suggestion. Wouldn't it be easier to just ignore the heat problems, pretend they don't exist?

 

Let me explain. As it turns out, your handwaving is more or less the same as a rather stubborn popular misconception that is the topic of many emails I get.

 

So if you take the easy route and ignore the heat problems, it's better for you, it's better for me, and it's better for any of your players that might decide to email me.