Need a scientist?

[springs]

Um, I think I need a lot of scientists.

Again, I'm not trying for hard sci fi on any level but there are a couple of things I need to sharpen up a little - a lot, actually.

1. I have a port which I'd like to be self-defending once shields are up ie if there is enemy fire it is repelled back to the source. Is there a type of shield could do this? Ionic?

2. the port also has the capacity to fire plasma bolts when shield is down; if shield went up would such bolts be able to pass through? I can work around it if not.

3. The system/galaxy I have this in has a centre of 12 planets and associated satellites with around 30 planets around what I've described as the outer rim although this is more to do with their proximity to the centre of government than any spacial consideration. Is this big enough for a galaxy/too big? I'm not going to get into light years etc as I think it takes me into detail that will confuse the book/slow it down.

Thanks to anyone who can help

[The Judge]

Can't help you with the port thing, but about (3) you do realise that galaxies are big, don't you? Really big. You just won't believe how vastly, hugely, mindbogglingly big, to coin a phrase. The Milky Way (our galaxy) contains 200-400 billion stars. Even if only a tiny percentage of them have planets, that still an awful lot.

A system is presumably a solar system? ie the planets around one star? 42, even 12, might be pushing that a little, I'd have thought, if they are all meant to be habitable. As you can see from our system, you need a Goldilocks planet, one that's not too close to the sun, not too far away, but just right, to sustain life. I don't know how many could jostle into that amount of space without affecting each other adversely with their gravitational forces.


EDIT: don't know if this will help, but the pictures are pretty http://en.wikipedia.org/wiki/Milky_Way -- about half-way down it talks of a Solar Interstellar Neighborhood [sic] which might be more the name you need rather than system, perhaps?

[springs]

So maybe two/ three systems in close proximity or a galaxy in which the forty or so planets are the habitable ones? Assuming they may have extended the parameters for making a planet habitable?

[Venusian Broon]

Hey Springs,

for (1) You could either go for a 'thingy-ma-jig' technolgy and just give it a cool name and exactly the right sort of properties - for the example the city-wide shield of Arrakis in Dune is not really made physically 'right', but we know that 'atomics' are required somehow to break through them.

or

we'd have to know what the enemy fire is to try and guess what sort of shield might stop it. (and what you mean by plasma bolts - real plasma?)

If you take first approach then you can build whatever property you need to satisfy (2) with of course.

As for (3) - when I was building my universe for my current WIP I said that there was probably ~130,000 earth size planets at the right orbit in our galaxy. But it all is based on very rough estimates that can be fixed to give you practically any number.

I could post/mail you my research notes on the calculation if that helps.

[Abernovo]

Another common way of adding planets is by having habitable moons orbiting gas giants in the Goldilocks zone of a star. One thing that always bothered me about this is that, in orbiting the gas giant, the moons will go behind it and be blocked from the sun for a period of time, but it's never, or rarely, addressed. It could work for you though, in adding extremely cold, two week long (or whatever) nights every X months. The other thing that moons can do to a story is show differing gravities from each other and from the habitable planets in the system.

If you're looking at wiki's Milky Way page, you might also want to look up stellar classification. Not all stars are the same colour, obviously, and this affects the distance of the Goldilocks Zone from the star - red closer in, yellow further out, orange in between. Just as a (possibly useless) note of interest, it has been suggested that plants' leaves under a red sun might appear black or dark brown as opposed to green.

[chrispenycate]

I'm not sure I dare answer a Springs science question; I show a slight but definite tendency to freak her out.

There is no type of shield which would repel electromagnetic (laser etc.), kinetic and particle weapons. If you need one, I'm afraid you're going to have to invent it yourself, which has the advantage that you can specify exactly what it needs to do.

A solid, material screen (say a perfectly reflecting superconductor sheet) has the disadvantage that it has inertia, so would take time to put into place. If multilayer, it can reflect back laser beams (and superconductivity dissipates the waste heat at the speed of light), while electric currents circulating in it generate magnetic fields which dissipate particle beams, or plasma (which is by definition ionised). Which leaves us bunging kinetic energy weapons at it (like Roman catapults) or impact fused nuclear rockets. Since we can see these coming, we can try and burn them up with laser weapons; easier for warheads than mere fast moving lumps of rock.

Force fields presumably propagate at the speed of light. We don't actually know, because we can't yet generate them. This makes 'closing the door' much faster. A gravity generator, if one could be built, would make quite a good shield, assuming it could be given a sufficiently high gradient – a sort of black hole a picometre thick. What you would get off it in the way of radiation when it was tuning on or off, and the energies involved, I don't really want to know. And you wouldn't be able to see through it, so you couldn't know when it was safe to turn it off, let alone be able to lob plasma bolts back. A spindizzy lets visible light through, so is useless against lasers and their ilk. A stasis screen allows no time to pass inside the shield, so the on-off switch has to be outside the shield itself, as does the generator, otherwise it can never switch off; which is a pity, as otherwise it would protect against anything, including siege.

A scanning shield (a point shield, like say a quantum black hole moved across the area to be covered like the electron beam in a TV set, although much faster, obviously) a percentage of radiant energy would get through, and, if you synced things perfectly, you could get your plasma bolts out. Unfortunately, if the enemy could analyse your pattern, they could get their plasma bolts in, so perhaps that's not so good an idea.

Or invent your own; nobody can contradict you.

As regards sizes of stellar configurations, Galaxies are big; why not go for a stellar cluster; a hundred or so stars, many probably have planetary systems, a few inhabitable planets or moons (after terraforming; I don't expect to find many use as delivered), plenty of loose junk; radiation levels probably a bit higher than on Earth, but hey, like that you can evolve faster…

[Vertigo]

1. Any kind of shield is inevitably speculative in nature as we have no technology to produce such a thing right now. So you could theoretically give it any properties you wish. However I would personally think a shield that actually repells the enemy's fire back at them would be pushing believability. If you are talking physical weapons like missiles then I would say definitely no. If you are taking beam weapons then they could possibly reflect the beam in some way but the chances of that reflection going straight back at the attacker would be slim.

2. Most people using shields in their stories generally drop the shield for a microsecond or so whilst their weapons are firing. Again it would be pushing believability a little to have a shield that let stuff through one way but not the other.

3. I think having more than two or three planets in the habitable zone is unlikely however, further to Abernovo's post, they were talking on the last Sky at Night about the perfectly reasonable possibility of a gas giant in the habitable zone (they have actually detected a system with a gas giant so close to its sun that it orbits in a matter of days). Now such a gas giant could have multiple moons all of which would share it's position in the habitable zone. Though as Abernovo comments few authors seem to give much consideration to the long nights you would experience whilst in the gas Giants shadow. Of course that assumes that the gas giants moons orbit in the same plane as the star system's ecliptic. If the gas giant's moons orbit orthogonally to the star systems ecliptic then, although they might be spinning (ie. not tide locked) they may still only present only one face to the star itself which would be their poles.

[springs]

Chrispy I cannot tell you how much I enjoy a Chrispy response - I do not neccesarily understand said but I always read with much interest
Seriously ty to everyone my understanding is the shield's okay supported by a weaponry system as opposed to firing back indepently and I could go with linked solar systems with a nice Imperial name see how I totally bypassed the science but it's all sinking in and appreciated

[David B]

Originally Posted by springs1971

3. The system/galaxy I have this in has a centre of 12 planets and associated satellites with around 30 planets around what I've described as the outer rim although this is more to do with their proximity to the centre of government than any spacial consideration. Is this big enough for a galaxy/too big? I'm not going to get into light years etc as I think it takes me into detail that will confuse the book/slow it down.

There are approx. 1,400 star systems within 50 light-years of Earth containing 2,000 stars (due to binaries etc.). This should accomodate the number of habitable worlds you are using. The following link gives a good overview map:
http://www.bibliotecapleyades.net/vi...sp_hall02a.htm

Equally, if you want to generate planetary systems, try stargen:
http://fast-times.eldacur.com/StarGen/RunStarGen.html

[springs]

Originally Posted by Venusian Broon

Hey Springs,

I could post/mail you my research notes on the calculation if that helps.

Verusian, many thanks; I suspect it would totally bamboozle me but I really appreciate the offer.

[Arkose]

Anyone know if your mining for turquoise would acid drainage be a problem? I understand what acid drainage is, but most research has looked at coal and metal mining. I figure it would be the same since turquoise is usually found with/same family as copper. Since I am more of restorer (stream restoration, fixing acid drainage, and what not) and not a full chemist/geologist, I figured I should ask first.

Thoughts?

[Rider of scaled wing]

I'm sorry i don't have an answer for you Arkose, i came here with a question i needed answering.

The story i'm working on concerns dragons, as you could probably tell from my avatar i'm a huge fan of the big beasties. what i'm trying to figure out is an aspect of a 'realistic' biology of dragons. in particularl, massive ones. Like, the size of a whale massive.

To support them in land based motion, and flight, their bones need to be remarkably strong, and lightweight by proportion to their size, i've got that figured already, but i suddenly had a thought about their scaled hides. I've allways thought of them has being no thicker or tougher skinned than, say, a crocodile. With some smattering of 'scutes' on their hides, scales that are large, and hard like a turtle's shell. However, soem recent discussions with a clsoe friend of mine made me think of 'what about all the forces that the hide has to deal with? not only from the outside, but also from inside their bodies? all that weight, all the motion of those huge muscles, and their own bodyweight, would that require an exceptionally tough and flexible hide to be functional? would having a 'averag'e hise mean they'd be getting skin tears constantly, or am i talking nonsense?

[chrispenycate]

We know (from dinosaurs, if nothing else) that the reptillian structure can accommodate great size in a land living creature- even large crocodiles demonstrate that there should be no problem with getting hide tough enough. What's more, the "cube-square" law, which is what is hitting you on the skeleton, does not hold for skin, which is surface area, not weight (=volume). An elephant's skin need be no thicker, in proportion, than a mouse's.

Obviously, wing surface area (normally wingspan, but perhaps other forms would be more effective at large masses) increases faster than linear length, and skin strength there (as well as rigidity of support structure, probably bone) gets rapidly critical, but you weren't going to put scales there, anyway, were you? Yes, I do see your user name, but…

[Rider of scaled wing]

The scales are usually on the 'struts' or digits on the wing, or anywhere there's muscle and bone. but i digress.

Thanks Chris. you're so widely knowledgeable. it's amazing.

[hopewrites]

So I was looking up on how to make skin blue, and I found a skin condition that occurs when silver is applied or ingested for a period of time over a persons life and their skin becomes the depository for the excess mineral and when the person comes in contact with the sun they turn blue.
I wanted to use this for the basis for why a group of people on my post-apocalyptic (6-12M post-apocalyptic) world were blue. Can it be hereditary (as in they are no longer drinking silver infused water) or would they still need to be ingesting it. Also how soon after a deployment of Mutually Assured Destruction level of nuclear bombing would silver-infused water not be a contributing cause of radio-active death?
It's a fantasy story not a sci-fi, but I dont want to be blatantly wrong about things.