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Need a scientist?

MemoryTale

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The scenario I've used is that barrels of flour were fired into the enemy ranks with catapults, before the airborne flour was detonated using a rudimentary explosive. Is that feasible for causing damage?
 

hopewrites

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sounds to me like you'll need to get it out of the barrels. i would guess with some kind of giant bellows (at which point someone could make a derisive comment about how they like their chicken baked not fried [you said no oil]) once sifted into the air above the entrenched enemy besiegers, then you would detonate it.

I have no idea actually, that's just my interpretation of what was said before.
 

Vertigo

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Actually that might just work; the impact of the barrel smashing into the ground would probably disperse enough flour to be flammable (make it reasonably weak so it smashes open - maybe some sort of sack of flour might even work better). I don't think you would get an explosion in the normal sense of the word as it would not be contained. However you would probably get a fireball of some sort. Which might even do more damage to unprotected foot soldiers than an explosion would.
 

Piousflea

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How powerful is an explosive based on flour mixed with air? In my WIP, a beseiged castle uses flour barrels as an improvised defense. The intended result is the destruction of incoming seige equipment and the first couple of lines of the enemy army. The more traditional route of oil vats + fire isn't really an option in this scenario.
Fuel-air mixtures are pretty badass, and we've seen the Mythbusters do it with wood chips, sawdust, and coffee creamer. Flour is certainly plausible. The difficulty is in rapidly mixing the fuel and the air. The Mythbusters used a very large blast of high pressure air. Modern fuel-air bombs use a series of two explosive charges - one to disperse the fuel, and a second one to detonate it.

Relying on impact with the ground would probably result in a very weak fuel-air blast at best. It would work much better if the flour was under pressure. For example, use bellows to pressurize a large air bladder on the inside of each flour barrel, prior to loading the flour into catapults. Then fire the catapults, then fire flaming arrows, and BOOM. Fuel-air bomb!
 

MemoryTale

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Thank you all, HopeWrites and Piousflea have especially given me a better idea of how this strategy would work. I feel a bit silly for not having thought of it actually
 

Jo Zebedee

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Ooooh, remember this thread? Okay, scientist types....

I have a scenario where an alien space ship is sending out beacons to its civilisation to come and rescue it. I have this scenario to cause a general malaise amongst humans in contact, and the surge is strong enough to kill small animals.

The setting is a forest. Would a surge taking energy/causing energy depletion in mammals also have an effect on plant life. Ie would you buy it that it takes organic energy in whatever form it could find? I mean, mammals are organic, aren't they? And so are trees?

I hope this makes sense. I have my doubts.... ☺
 

chopper

Steven Poore - Epic Fantasist & SFSF Socialist
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so the energy pulse draws from all life around it, but is indiscriminate enough to kill small animals... and probably all insect life too. as plants etc don't have heartbeats, would they wither & regrow as they draw nutrients from the soil once more? would the ground itself become less fertile?

sorry, more questions :)
 

Venusian Broon

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If your signal is E-M in nature, then putting by hard science hat on, I can't see how you can simply 'target' small mammals etc...:)

So if, to give an example, the device was causing powerful secondary microwaves, then everything with water in its body, both plant or animal, that receives a big enough dosage will get cooked. Similarly, hard radiation such as gamma-rays, or alpha and beta particles won't make a distinction - they are just interacting with what ever matter 'they' find.

You might be able to argue that some species (and that might be certain trees) are naturally a bit more resilient.

In fact of the signal has been going for a very long time, the local flora and fauna could have adapted to it better (and evolved if long enough) - while species that are alien to the region would be likely die off very quickly - This might give you the effect you are looking for?

Do you have a clear idea what the signal really is? (Possibly there is another way...let me think!)


EDIT - oh of course - In Stephen King's Tommyknockers....

the alien artefact in the ground deliberately tries to change the environment so that when it's making aliens these can actually survive on Earth (which is I believe poisonous to them). So perhaps the beacon does a bit of that. It also means you can be a bit more specific (and hand-wavy!) on what is killed or affected by its presence.
 
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Jo Zebedee

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The signal is new, and I thought the size of the animal might dictate the damage being done? I need it to be something dangerous to humans, but not killing them immediately. I'd also like it to be something recoverable from. And the purpose of it needs to be signalling out for a pick-up. Other than that, I can play around with how, what sort of rays etc. :D

You guys are brill. I am still a scientific amoeba...
 

Venusian Broon

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I think (not being a radiation specialist, so I am all ears for a definitive answer :)) that for some sort of radiation problem you are describing, yes, the bigger the animal the lower the surface area to volume ratio - and so in principle I think bigger animals would survive a dose that would kill a smaller animal. Eventually as well, I'd expect a dead patch of vegetation closest to the source if we are going for a hard science answer - but there will be a degree of resilience as well here, so some big trees might hang on in and just slowly die.

They always say that cockroaches and rats would rule the world after something like a nuclear-war devastated world, but I think that is because these types of animals generally live in protected nooks and crannies. And there's huge numbers of them and they eat anything.
 

Venusian Broon

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Another idea Springs (then I must go off and continue MY RE-WRITE!!! :D)

I tried to see if there was any real world examples of what you were saying - and my current conclusion is that the magnitude of radiative intensity that would be required to kill would be so blinkin' enormous that it should stand out like a very sore flashing thumb. (although I suppose that's the purpose of a beacon, isn't it :))

What if instead the signal is strong but doesn't directly kill. i.e. it induces the local vegetation into secreting some substance - that the plants use to protect themselves - but as a by-product is specifically toxic to mammals? Again the big better rule would work in this case.
 

Ray McCarthy

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What sort of organic energy? Best not to say, as there isn't really any such thing.

Radio "Radiation", Xrays, gamma rays, beta radiation, neutron radiation, radioactivity generally etc all have very different properties.

Radio is "non-ionising" radiation. Basically it heats the object purely based on how much "loss" the object causes. Most objects are more lossy at higher frequencies. 8MHz may be fine for RF welding some materials. But to "cook" organic materials the 1500MHz and upward is better (Microwave ovens use 2500MHz approximately). Inverse square law applies to strength from source and type of organism doesn't matter. A microwave oven with no door will give you cataracts, not cook you or give you cancer. You need ionising radiation to trigger cancer. Radio is very low frequency Electromagnetic Radiation. It's quite different to Radioactivity or even X-Rays (which are Electromagnetic)

The susceptibility to Radioactivity or ionising radiation damage varies widely with species. Water bears are the most resistant. Generally it's worse for animals than plants and worse for larger fleshy animals with no exoskeleton. There are different kinds of particles. Alpha radiation is dangerous (basically helium nucleus) Beta radiation doesn't penetrate or so easily damage as it's electrons. Neutron radiation makes what it hits very radioactive. Air attenuates beta radiation.

[Edit I added some wiki links]
Gamma rays
X-Rays
Neutrinos hardly affect anything. Most will even pass entirely through the Earth

You can have Neutrinos or Radio as beacon. Ordinary Radioactivity won't work.
 
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Venusian Broon

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I'm like a big terrier with the bit between my teeth chasing after...whatever terriers chase after, Springs - so after sleeping on it :)

More thoughts:

You can have Neutrinos or Radio as beacon. Ordinary Radioactivity won't work.
This is true for the signalling part.

But your beacon will require a power source (and if it is a big beacon, it will require a big power source). Hence could be leaking radioactivity, heat, strange hums and vibrations or whatever you so desire, to make a your story work!

(or you could push the boat out of and make it do something just outside current known science and make it twist space-time and pulse gravity waves or access other dimensions off the brane universe etc... Personally for me in these cases - as long as it's consistent, your universe is your oyster. But I digress. :D)
 

Jo Zebedee

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I think the ship could be the power source easily enough. The beacon has come off the ship as it crashed - by design, I thought, somthat in the event of a crash the beacon survived. And yes, evidently it's some sort of alien technology that I don't have to describe or understand since my 15 yo protagonist will never know the details.... D
 

Ray McCarthy

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I doubt many people any age have any clue how existing beacons work.

@springs
A chemical used as REAL coolant in transformers on electricity poles is bad enough!
http://en.wikipedia.org/wiki/Yushō_disease

An organic chemical can have species specific poisoning effects. Some chemicals used in batteries (Mercury in the past and mysterious Organics now) are gruesome. As are some Bromine based fire retardants (quite likely in the beacon & power supply).

So you can have believable nasty stuff without making up unlikely radiation types for the actual beacon transmission!

I'd personally go for a leaking chemical. I like to save the fantasy science for something irreplaceable like Jump Drive, Cyborg Telepathy, Portable Fusion Generators etc.
 

Ray McCarthy

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The plants and insects might not thrive :)
But I do think fun for the writer and very believable.

Initially it affects small things most. Only later are larger trees and predators etc. affected. Isn't that what you wanted? Radiation can affect the large mammals worst.
 

Jo Zebedee

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Thread revival! Quick science question - bear with me as I phrase it clunkily. I know that the body we see in the sky - be it the moon or a star - is not the real-time object but one from however long ago, based on the speed at which we see it. (So, I see Ursa Major - the star, not the bear! - and the light I'm seeing is from years ago. Ursa Major could disintegrate and I'd not know)

I'm wondering how old the real-time Jupiter I see is? Does that make sense? If I'm looking at Jupiter tonight, how long ago would that vision of Jupiter have existed?
 

The Judge

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Presumably one could calculate it by taking the average distance Jupiter is from Earth and the speed of light and doing something mathematical with them.

Here's a link which gives details of how far Jupiter is from us How far away is Jupiter from the earth

My wizard with the calculator says that at Jupiter's nearest, light would take 2100 seconds to get here, or 35 minutes.

Apparently it's between 4 and 6 times the distance the sun is from Earth. It takes on average about 8.25 mins for light to reach us from the sun, so just multiplying by 4 would give 33 mins.

So, we're seeing Jupiter as it was about half an hour ago. Which doesn't sound very much, somehow, so may well be utterly wrong!


EDIT: I'm right!! How long does it take for light from Jupiter to get to the Earth?

about half an hour. On average, Jupiter is 5.2 AU from the sun and Earth is 1 AU from the sun, So its about 4 AU from Earth to Jupiter on the average. Light crosses 1 AU in about 8 minutes - so maybe 32 minutes.
and
Right now, about 35-40 minutes, give or take. But that changes every second, because Jupiter is now moving away from Earth.
 
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