Month: April 2014

A Song Without A Tune

Good Advice

“Write every day.”

It’s one of the basic tenets of the writing life: if you’re not writing, you’re not a writer, and you need to write every day to keep learning, to stay in touch with what you’re writing, and just to finish stuff. It also echoes the good practice of tackling big tasks a little at a time.

Bad Practice

What with one thing and another, I haven’t done much work on Song recently.

The problem with not touching a story every day is that you lose context: you forget the feel of the characters and the narrative in your head, then when you come back to it there is nothing to say. It’s not writer’s block, this emptiness – it’s disinterest.

How to reattach to the story, then?

Some ideas:

  • reread it – I’ve done this before in this drafting stage, before I dug in on act two. Maybe a reread is the right thing as I roll into act three also.
  • implement some notes – I’ve found some notes on things broken with the story, things like a new character invented for no good reason when there is more useful character to hand already. Fixing that kind of bug would reacquaint me with the narrative. This is the writerly equivalent of learning your way around a code base by fixing bugs.
  • skip time – I stopped writing when I was mired in a scene I don’t know how to bring to a conclusion. I could skip past that scene and write the next one I have something to say about. The skipped scene will still be written, just when the context is better embedded in my brain.

It’s not hopeless, of course. I really just need to spend some time with the story again.


I do write every day, just not always on the things that serve my long term goals. What with the day job, the demands of family life, and my irritating habit of accreting hobbies and projects I somehow end up with almost no time to spend on The Work, and those times are often the lowest quality: early in the morning, for example. I can be productive at 0500, but that productivity is fragile.

So, the reality is I need to figure out how to apply not just an amount of time, but time that is worth making use of.

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Training For A Race

June's race

my race in June

I have a half marathon I am signed up for in June. In fact, it’s the first Saturday in June.

I ran a 15K in March (9.3 miles), but the farthest I have run since then was a hilly seven miler on Wednesday last week, so I have some work to do.

Basically, I want to run a twelve mile training run two weeks before the half itself, which would need to be the weekend of 17-May-2014. I need to ramp up another five miles in four weeks.

Fortunately, I also ran another hilly seven yesterday and there is a pretty straight line from that seven to the twelve miler as follows:

  • 26-Apr-2014 – eight miles
  • 03-May-2014 – nine miles
  • 10-May-2014 – ten miles
  • 17-May-2014 – shorter run, probably the seven I did yesterday again
  • 24-May-2014 – twelve miles
  • 31-May-2014 – shorter run, probably something like five
  • 07-Jun-2014 – Helvetia Half marathon

The other thing I need to do is figure out the training plan for Hood To Coast in August, especially in amongst our holiday plans.

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Scheduling Change

Making official what has been de facto for a little while, I am dropping the post frequency here to once a week. The intent is to make these less-frequent posts more substantive, but really it’s a load issue: writing the blog to the standard I want is not compatible with doing any other writing at all, really.

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The Science of Science Fiction: Sunlight and Shadow

corn-by-jupiterlightThis is another post about making your story more credible by applying some science and maths.

Story Parameters

“You know moons are tidally locked, don’t you?”

Once upon a time I was talking to a friend about the setting for Bluehammer, and I mentioned that it was set on a moon orbiting a gas giant. I had already figured out that there would be a certain amount of time when the parent planet would occlude the sun from the moon, and in the interests of minimizing the amount of time in the day that this occlusion would last I put the moon in an orbit that would take a couple of weeks to complete[1],

But my friend was right: every moon in our solar system – even the asteroid captures like Phobos and Deimos around Mars – are tidally locked: the same face always points towards the parent[3].

For the orbit that my moon was in, that meant that its day/night cycle was a week[4] of darkness followed by a week of daylight. The planet-ward side would always at least have the parent planet in the sky to light the way, except during the period of occlusion.

Would that glowing ball in the sky be enough for earthly crops to grow?

The answer to that required two pieces of information:

  1. how big would the parent planet appear in the sky?
  2. how much of the local star’s light would be reflected?

How Big In The Sky

The interesting thing about gas giants is that Jupiter is about as large as they get, in terms of volume. They can be more massive, but the actual diameter of the body won’t increase much because the gas will just compress. So, I used the radius of Jupiter and the orbital dynamics of my moon (particularly the orbit’s radius) to figure out the angle subtended by the parent planet in the sky. I put my moon in about the same spot as Callisto, and those are the numbers I use here[5].

Orbital radius: 1.88×106 km [6]

Diameter of planet: 1.4×105 km

The angle we want is at the pointy end of a very extended isosceles triangle. An isosceles triangle is two right angled triangles back to back, so if we calculate the small angle for one of those and double then that will be subtended angle of the gas giant in the sky.

Formula: tan(θ) = Opposite / Adjacent sides

Adjacent side = orbital radius = 1.88×106

Opposite side = radius of planet = diameter / 2 = 7×104 km

tan(θ) = 7×104 / 1.88×106 = 3.723×10-2 = 0.03723

θ = tan-1(0.03723) = 2.13˚

parent planet subtended angle = 2θ = 4.26˚

That is about eight times bigger than the moon’s subtended angle of 0.52˚, which of course happens to be about the same as our Sun.

How Bright On The Ground

The amount of energy reflected from a planetary surface is the albedo of that surface.

The obvious comparison is with our own moon, which seems nice and bright in the sky, at least at night when it is full[7]. What is surprising is that the Moon’s albedo is really low at 0.12 – it’s comparable to that of coal. By contrast, Jupiter has a much higher albedo of 0.52, so that much more of the Sun’s light is reflected from that surface.

So, let’s say that 50% of the local sun’s radiation is reflected back from the parent planet.

That’s going to work out, right? A body in the sky eight times as wide as our Sun reflecting five times as much light as the moon will light the sky enough to grow crops, yes?

Possibly not.

The difference is between emitted and reflected light: our sun emits a lot of energy, and we are primary consumers of it – the surface of Earth absorbs the energy from the Sun directly.

By contrast, a planet is a convex reflector so the relevant calculation is not just what angle the parent planet subtends in our sky, but what angle the child moon subtends in the gas giant’s sky. That will tell us what minuscule proportion of the local star’s energy received by the planet will be reflected back onto the moon.

Callisto’s radius = 2.4×103 km

Orbital radius = 1.88×106 km

tan(θ) = 2.4×103 / 1.88×106 = 1.277×10-3 = 0.001277

θ = tan-1(0.001277) = 0.073˚

Callisto subtended angle on Jupiter = 0.146˚

Let’s say that the sky is 180˚ wide:

fraction of sky angle = 0.146˚ / 180˚ = 0.000813 = 8.13×10-4 = ~0.08%

… except the sky is not a line, so we need to square that proportion to get the actual fraction of energy reflected from the parent planet.

fraction of sky area = 8.13×10-4[2] = 6.6×10-7

Oh, and halve that again to account for the albedo

proportion of energy received by Callisto = 3.3×10-7

Wow – that’s not a lot. But what does it mean?

Well, let’s say that the amount of energy collected by this moon is 1. The amount of energy collected by the parent planet is more than that, related to the relative surface area of the planetary disc.

Callisto radius = 2.4×103 km

Jupiter radius = 1.4×105 km

Area of circle = πr2

Jupiter : Callisto disc ratio = Jupiter disc area / Callisto disc area = (1.4×105)2 / (2.4×103)2 [8] = 1.96×1010 / 5.76×106 ~= 2×1010 / 6×106 = 0.3×104 = 3×103

In other words, Jupiter collects about 3,000 times the amount of solar energy that Callisto does, but Jupiter reflects back to Callisto 3.3×10-7 of that: 3×103 x 3.3×10-7 = 10×10-4 = 1×10-3

Jupiter’s reflected light is about a thousandth of a Sun.

Which is a lot more than the moon gives us, but not likely to be enough for healthy crop growth.

So, I had to think of something else, but that is another story.

Fermi Estimation

I mentioned Fermi estimates in my last post. This TED Ed video is a good introduction to these kinds of order of magnitude estimates.

[1] I also wanted to put it that far out for other reasons: so that the moon could have its own satellites, and so that the tidal forces on the moon would not make it unsurvivably volcanic. Living on Io would be tough in part for that reason[2].

[2] and also because Io is a toxic ball of sulphur.

[3] Pluto and Charon are mutually tidally locked, another point against Pluto being considered a planet in my book.

[4] a “week” here meaning seven Earth days. These words get slippery when not dealing with Earthly rhythms.

[5] my moon is a little larger than Callisto and so orbits a little further out.

[6] using kilometres rather metres since these are large scale distances, but the units will also cancel out for these calculations

[7] this brightness is partly because the moon’s surface has a strong opposition effect: it looks brighter when the light is behind the observer. That’s not relevant for the reflectivity of a gas giant, however.

[8] the π factor cancels out

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The Science of Science Ficton: Estimation

poison-waterWhen writing science fiction, sometimes you have to have some science in there.
The science can come from many places, but one skill that is useful in applying it is estimation1: taking observations and extrapolating them. Sometimes this is to answer specific questions, other times it might be to define the parameters of the story.

A Note On Units

When doing these kinds of estimations, using metric units helps. A lot. I am happy enough to convert metric units into US or British Imperial units for presentation2, but the equalities built into the metric system make these calculations much simpler.

  • 1 litre = 1,000 millilitres
  • 1 mililitre = 1 cm3
  • 1 mililitre of water weighs 1 gram3

I also recommend using exponential notation since that makes comparing and cancelling orders of magnitude much quicker.

Finding An Answer

This is some research I was doing for A New Dawn: how much poison do you need to poison a reservoir?

Some context which might help to explain my search history – the bad guys in A New Dawn are prosecuting a terror campaign against the good people of Portland4. Portland gets its water from snow melt collected in a system of reservoirs called Bull Run.

If you were wanting to scare people, how much nastiness would you have to put in the water?

Wikipedia tells me that Bull Run has been measured to hold between 4×107 and 6×107 m3 of water5. For the purposes of easy calculation, I round that out to 5×107 m3. There are 1,000 litres in a cubic metre, so that’s 5×1010 litres.

Now, what’s a good poison? We’re looking to scare people here rather than kill them, so let’s pick something non-lethal, and of course water-soluble. For no particular reason, I settled on LSD.

One of the amazing things about LSD is how potent it is: the threshold dose is 20-40 µg – that’s micrograms – and a normal dose is in the 100-500 µg range. Again, for the sake of ease of calculation, we’ll aim for a dose of 100 µg.

Let’s say that in order to get the dose into the people they will drink 100ml of water, which is two fifths of a US cup. So, in our reservoir of 5×1010 litres there are 5×1011 drinks.

Therefore, we need:

100µg = 100×10-6 g = 1×10-4 g for each drink, which is 1×10-4 * 5×1011 = 5×107 g of LSD

Let’s say that the LSD we are talking about is a fluid of similar density to water, so that the weight we talk about can be translated into volume directly. This is a highly dubious assumption, but it’ll get us close enough.

5×107 g = 5×107 ml = 5×104 litres

For the sake of argument, let’s say we pack the LSD in 55 gallon drums. Now it so happens that 55 gallons is about 200 litres, so you would need:

5×104 / 200 = 2.5×102 = 250 x 55 gal drums

… which is rather less than I expected, in fact, although it’s still a lot: right around 50 tons.

Back to Reality

Is this a credible threat for a reservoir the size of Bull Run?

No – or at least not in our world. Moving that weight would take five ten ton trucks, and the forest roads are not built for that kind of vehicle. The bad guys in A New Dawn of course have other resources which I will not go into here, but even so 250 barrels is a lot.

I toned things down for the game, in the end, loading up a boat with 75 drums instead, since I figured that would still deliver a threshold dose, especially if the victims drank more than half a cup of water.

[1] the sine qua none of estimation is Randall Munroe’s What If? site. There’s a useful discussion of Fermi estimation there too, which would be valuable for capturing the basic plausibility of a notion.

[2] I won’t talk about the differences between those two systems, except to note that the US label “standard units” is gratuitously wrong.

[3] at Standard Temperature and Pressure, to be sure, but the variance in human-habitable environments isn’t high

[4] and the bad people, of course.

[5] to reinforce my point about units. the figure on the Wikipedia page is first given in acre feet.

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Details, details

some details are more important than others

some details are more important than others

We make worlds and people to live in them, but we cannot possibly pour all of that onto the page. Instead, we must evoke setting and character by the use of precise details and choice of words.

I am thinking here, of course, of fiction where the intention is to tell a story rather than to fully describe the place or the person. In this case, the description applied to the elements has a couple of basic goals:

  • to make the elements serve the story
  • to make the elements distinctive

Serving the Story

“If in the first act you have hung a pistol on the wall, then in the following one it should be fired. Otherwise don’t put it there.”

Anton Chekov

Characters do surprising things, but readers feel cheated if those things are not seeded in the story: if a character has been hobbling about on a walker for the first hundred pages and then suddenly casts off their shackles of infirmity to chase after that criminal who just robbed the bank with no hint that she was someone else, or without some other kind of transformative event, then the reader may well cast the story aside.

Settings need the elements to be there to support the story. A nursery with a shotgun hidden under the baby’s bed only makes sense if you’ve seeded the idea that the nursery may not be all that you would usually expect – hints of the babysitter’s history as a drug runner, say, or the parents’ desire to be ready for the zombie apocalypse.


“We will add your biological and technological distinctiveness to our own.”

the Borg, Star Trek: The Next Generation

I’ve just started reading Redshirts by John Scalzi and I have been very struck that there is almost no physical description of the characters, and yet they are all distinct because of how they talk and what they speak about.

The details we put in need to be enough to be sure who is doing what.

Names help, of course. Having major characters with differing initial letters or at least easily distinguished names on the page helps make it clear who is speaking. Making physical descriptions clearly different – or even subtly different, if you focus on the subtleties – helps clarify who is acting.

Similarly with settings. We can’t put in everything* so we have to describe what makes each location distinct from the others, whether it’s the insect-crusted ceiling of the cave or the Louis XV sideboard in the sitting room rather than the Louis XIV.

How do you decide what to put in and what to omit?

[*] and this was one of the basic problems with Bluehammer, that I tried to.

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