Posts Tagged Help!

Showing My Math

So here’s the deal. I’m working on a new project and I want to make sure at least some of the details have actual technical grounding. I’m okay with a little handwavium, it’s probably unavoidable, but I want to at least have some grounding in reality. Problem is, I’m not all that great at actual technical grounding, as the last physics class I took was non-AP physics in high school where I barely got a B. So I might occasionally make these posts, I might make just this one, in an attempt to crowdsource some of my equations. The questions I have are whether I’ve got the right equations, and whether I’m using them correctly, and to also play around with LaTeX a little. But mostly the first two things.

So here’s today’s problem: Given a cylindrical space ship with an internal radius of 6km, how fast must it be rotating to create a centripetal acceleration equivalent to earth gravity for someone standing on the inside surface? I didn’t know any of these equations, but found them at this rather helpful forum post. First, we must find the speed at that 6km point that would produce an acceleration of 9.8m/s²:

a=9.8 \frac{m}{s^2}
r=6000 m
v=242.49 \frac{m}{s}

That number sounds awfully damn fast, but consider the speed of rotation of the earth at sea level on the equator is roughly 465 m/s. Next step, at least what I’m assured is the next step, is converting this into radians/second:


Finally this can be converted to revolutions per minute. The conversion formula I found is:

1 \frac{rad}{s} = \frac{60}{2pi} = \frac{30}{pi} rpm
0.0404 \frac{rad}{s} = \frac{30*0.0404}{pi}=\frac{1.212}{pi}=0.386 rpm

Therefore the ship is rotating at a rate slightly faster than once every three minutes. What I didn’t expect is that, since the rate of rotation is a constant, centripetal acceleration increases linearly from the axis of rotation. I’m so accustomed to formulas for gravity having squares all over the place, but this isn’t, strictly speaking, gravity. It’s an acceleration equal to gravity. So at half the distance from the axis of rotation, we can work backwards with W as a constant…


a=\frac{121.2^2}{3000} = \frac{14689.44}{3000} = 4.9 \frac{m}{s^2}

Which is equivalent to half gravity.

My next trick will be to find a formula that describes the rate of descent for a body falling through linearly increasing gravity. That’s less likely to come up in-story, but more for my own curiosity.

Edit: Some further poking around (which, I’m ashamed to say, has mostly been at Wikipedia so far) suggests that 2rpm is about the maximum rotation that most humans can adjust to with no ill effects, so my rotation of nearly 1/6 that rate is shockingly safe in and of itself. So that’s good to know. Now if only it didn’t have a “citation needed” tag.

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An Experiment

Something unusual and entirely unexpected has happened in my neck of the woods.  A long-term road improvement project had the effect of actually improving a road.  I’m sure this is some massive bureaucratic oversight that will be corrected in the coming months, but for the time being, eliminating a pointless bottleneck on my morning commute has shaved fifteen minutes off my drive every morning.  No kidding, one bottleneck, fifteen minutes.

What this means is fifteen minutes of my day that I don’t know what to do with.  Yes, I know this is a good problem to have.  This morning I played a stupid zombie infection Flash game, which was nicely mind-numbing, but doesn’t feel like a legitimate use of that time.  I could set my alarm to go off fifteen minutes later, but fifteen minutes of extra sleep doesn’t seem worth it, especially because I’m sure I’d end up reading fifteen minutes longer each night figuring it balances.

So I’m going to try something really crazy.

I’m going to try writing during those fifteen minutes.

I’ve seen a lot of writers with day jobs suggest morning writing when trying to eek out bits of the day to wordsmith.  Some who go so far as waking up at 5am to pound out a few thousand words.  I’m not sure I’m going to go quite that crazy, but if I could get in a regular habit of five hundred words each workday before hopping in the car and joining the rat race each day, that’s 2500 words a week, and roughly 100,000 words over the course of a year, even if I took every day of leave I earn.  That’s three or four novellas, or a novel, or 20 long short stories, 100 flash pieces, or more likely some combination of those.  Assuming I can actually get my act together and do it.

That’s the rub.  Actually doing it.  Mornings are rough on my brain, and a big part of the experiment won’t be whether I can pound out 500 words before work, but whether those words will be of a quality worth keeping.  That’s why I’m going to focus on rough drafts in the morning, getting down broad ideas, things that can be polished later in the day when my brain is more fully awake and capable of perhaps figuring out why I wrote “larble poop whee” that morning.

If things go poorly and the words I’m writing down aren’t worth keeping, I’ll likely discontinue the experiment.  But not any sooner than two months down the road.  I’m not going to give up just because I have a rough first week, that’s no way to approach any job, least of all writing.  It’s going to take awhile to get one more routine into my brain each morning.

If things go well, I’ll keep going and have a lot of rough drafts that will need editing.

If things go brilliantly, I might try an even crazier experiment and even get up a little earlier and see what I can do with half an hour of writing time each morning.

I’ll be tracking my progress next week on Twitter, starting Tuesday (THREE DAY WEEKEND!).  As always, I find baring my plans and progress create an odd sense of obligation, even if none of you have ever held me to it in the past.


Nostalgia is a funny thing.  The word itself, I mean.  During the Civil War the definition was closer to what we would today call PTSD.  Anyway, I’ve been looking for a word for years that I swear I heard defined once, but have never found again.  It translated loosely to “nostalgia about an idealized past the feeler didn’t experience.”  In the mainstream it would be used to define a typical American attitude towards the 1950s as a time of no evils.  It’s the kind of word that I assumed would be German, but I’ve not found it if it is.

And yes, I realize this could be a definition of nostalgia itself, but I swear I once heard this word.

UPDATE:  My wife has passed along the word Sehnsucht, which fits the criterion of being a German word and describing a form of nostalgia.  It’s about 95% of the word I remember, which likely means it’s the word I heard and I don’t quite remember the definition correctly.  Still, I’ll leave the question up in case anyone has a more likely suspect.  A little further from the definition is the Portuguese word Saudade, which I am certain isn’t the word I heard.

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Ace Doubles

I’ve been to the used book sale at the local library several times.  Never walked away with much, largely because not much ends up speaking to me.  When I go into any used book store, I beeline to the Science Fiction section.

I will stop here so you can be suitably shocked.

Lately what I’ve looked for is old pulp.  What I sometimes call the “skinny novels,” the ones that fill the narrow gaps in between the inch-wide spines that dominate the shelves.  My local used book store, Hole in the Wall Books, has a fantastic selection of these.  The spines of Daw books give the entire room a yellowish tinge, and I dig through the titles, looking for authors I’ve never read or even heard of, but who are represented with a dozen titles.  I keep my smartphone on, looking up starting points in series.  Because of this I have books like Dorsai! sitting on my night stand, and am currently reading Destination: Void.  I don’t end up liking all of them.  That’s almost part of the fun.  They’re short, they’re cheap, so I feel better about not liking them.  When they end up corny fun (Dinosaur Beach) I enjoy the ride.  When I don’t (Assassins from Tomorrow) I start picking apart what’s going wrong.

When I go to the twice a year library book sale, I wander the shelves of intermingled fiction looking for these titles.  Nothing is sorted out.  Lord of the Rings sits next to Tom Clancy.

This last time my wife called me over to the hobby and craft section.  There, sitting in three cardboard boxes, were little paperbacks in Ziploc bags.  If they’ve always been at the book sale, I can tell why I’d miss seeing them.  Who’s going to look for pulp science fiction in the hobby and craft section?  Perhaps someone thought they fell under the header of being collectibles so they were shunted away with books on collecting.  Perhaps they’ve never had these books at the sale before.  I’m not sure.  All I know is they were there and I started to dig through them.

Among them were hiding the Ace Doubles.

I knew they’d printed books like that before, two short novels printed back to back, one upside down so that there are two front and no back covers.  All with the fantastic artwork that graced pulp fiction in the 40s and 50s.  All priced at $2.50 or $3.50 for the sale.  I maintained some composure, held myself to just six books, four doubles and two standalone titles.  I wasn’t picking authors, I wasn’t picking titles, I didn’t recognize most of them.  I was picking artwork and taglines.  How could I turn down a man in a white fright wig hooked up to a machine, with the tagline “The god-king, the man-wolf, and the I-machine”?  Flip it over and two men stand on a chessboard with rockets flying behind them.  Sold!

As I was digging out my wallet at the checkout, the volunteer mentioned that everything would be half price on Sunday.

Yes.  I went back.  I set a budget of $20, and I gobbled up Ace Doubles.  Ten more, bringing the total haul to 14 books and 28 individual stories.  It’s overwhelming, and I hardly know where to begin.  No, that’s a lie, I don’t know at all where to begin.  Among books picked at random I ended up with the first edition of a Hugo winner (Jack Vance’s The Dragon Masters), a story by the author of Dinosaur Beach (Keith Laumer’s Worlds of the Imperium), a story by one of the first major female science fiction writers, and screenwriter of the first draft of Empire (Leigh Brackett’s The Nemesis from Terra) and even a title just obscure enough that I got to add it to Goodreads (Robert Moore Williams’s The Darkness Before Tomorrow  paired with Keith Woodcutt’s The Ladder in the Sky).

So here’s a quick breakdown.  I don’t have cover scans of all of these, sorry, and I will likely read both halves of each Double before moving on to the next.

  • D-335.  Poul Anderson The War of Two Worlds (Earth must choose — The Martians or the monsters!) and John Brunner Threshold of Eternity (All time and space was their battlefield!)
  • D-479.  Wilson Tucker To Tombaugh Station (Was his spaceship haunted — or only booby trapped?) and Poul Anderson Earthman Go Home (This quarantined world resisted change.)
  • F-108.  Damon Knight The Sun Saboteurs (Exiles from a hostile universe) and G. McDonald Wallis The Light of Lilith (Trapped in time’s vortex.)
  • F-119.  Gordon R. Dickson SpAcial Delivery (Rendezvous with a double-sized goliath) and Delusion World (If you don’t look, she’ll go away!)
  • F-123.  Leigh Brackett The Nemesis from Terra (Caught in the web of the fourth world) and Charles N. Fontanay Rebels of the Red Planet (Was he man, mutant, or Martian?)
  • F-127.  Keith Laumer World of the Imperium (His deadliest foe was his own Alternate World self) and Marion Zimmer Bradley Seven from the Stars (Secret war of the space castaways)
  • F-141.  Robert Moore Williams The Darkness Before Tomorrow (Were all humans their guinea pigs?) and Keith Woodcutt The Ladder in the Sky (Black magic or unimaginable superscience?)
  • F-145.  Robert Silverberg The Seed of Earth (If your number is up, you go to the stars) and Next Stop the Stars (Exciting stories of wonders in new worlds)
  • F-149.  Robert Moore Williams King of the Fourth Planet (The god-king, the man-wolf, and the I-machine) and Charles V DeVet & Katherine MacLean Cosmic Checkmate (10,000 worlds against one)
  • F-153.  Marion Zimmer Bradley The Planet Savers (One body, two minds, and a world in the balance) and The Sword of Aldones (All lines of cosmic force met in their hands)
  • F-161.  John Brunner Times Without Number (Beware the masters of “if”) and David Grinnel (aka Donald A. Wollheim) Destiny’s Orbit (He sought an empire in the stars)
  • F-177.  Robert Moore Williams The Star Wasps (Cybernetic men versus the invisible monsters) and Terry Carr Warlord of Kor (Backwards world — or secret outpost to another galaxy?)
  • F-185.  Jack Vance The Dragon Masters (Which was master, which was monster?) and The Five Gold Bands (Find the five keys to earth’s freedom)
  • H-59.  Louis Trimble Anthropol (Secret mission to save a hostile world) and Philip E. High The Time Mercenaries (What port awaited the end of their thousand years beneath the sea?)

I’m probably going to put together reviews of them as I read them, just because I’ve been meaning to get into reviewing something on this blog.  So if you want my views on a specific one, let me know in the comments.  If you really need the covers to make a decision, Google image search for “Ace Double” and the letter-number combination I listed. Oddly, my inclination would be to not start with the Hugo winner, because I don’t want to potentially start with the best of the lot.

Wikipedia lists 224 total science fiction doubles (and several hundred more western, mystery, and non-genre doubles).  That means I now have just over 6% of them.  I’m not going to go super crazy.  I’m not going to buy things like this lot of 104 currently going for over $400 on ebay.  But I’ll keep my eye out for them in the future.  If you see them in and around the DC area, going for under $4 each (or especially under $2 each) let me know.


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