“See?” She asked.
I was distracted by how she looked, despite the grease. “I’m sorry, mechanics aren’t my strong suit.”
“Keep it spinning or we die.” That broke through long enough to analyze the instructions I was given.
“Why isn’t this automated?” I asked.
“Cylons.” The blank stare on my face led to a laugh. “It’s an old TV show, fiction. AI gained sentience, didn’t like being used as tools.”
I queued it for research. “I think I understand.”
That got a smirk, followed by a nod. “I’ll be in my bunk.”
A subsystem completed the research. It was…interesting.
Drabble is a form of extremely short storytelling, where you are limited to exactly 100 words. This one was written for a challenge, but not submitted in time.
This is related to Semi-Empirical Stellar Equations. I have had some questions easily answered, and others which are difficult or impossible to get the kind of accuracy I want.
I’m going to order what I’ve learned by the order I am planning to use these equations, marking equations loosely based on empirical data with an asterisk, and double asterisks for things I’ve completely made up to simplify calculation.
- Radius of Surface* (Rsurface):
5500km mean, 1550km standard deviation
- Density* [based on common rock types] (Dplanet):
4.7g/cm3 mean, 0.55g/cm3 standard deviation
- Volume [assumes a perfect sphere] (Vplanet):
4/3 * π * Rsurface3
- Mass (Mplanet):
Dplanet * Vplanet
- Surface Gravity (gsurface):
6.673×10-11Nm2kg-2 * Mplanet / Rsurface2
- Surface Area [assumes a perfect sphere]:
4 * π * Rsurface2
- Atmospheric Pressure Reduction Rate** (Pr):
Pr [unit: none] = -0.00011701572 [unit: s2 / m2] * gsurface
- Atmospheric Halving Height** (hd):
hd [unit: m-1] = ln(2) / Pr
- Atmospheric Volume at Constant Pressure** (Vsim):
(4/3 * π * (Rsurface + hd)3 – Vplanet) * 2
- Surface Atmospheric Pressure (Psurface):
Psurface [unit: kPa] = ???
- Lowest Safe Orbital Height** (h0):
h0 [unit: m] = ln(1.4×10-11 / Psurface) / Pr
- True Atmospheric Volume (Vatm):
4/3 * π * (Rsurface + h0)3 – Vplanet
Vsim exists to support a simulation of an entire planet’s atmospheric contents using my simple fluid simulation mechanic. The magic constant used to calculated Pr is based on Earth’s atmosphere, it can be changed to set an exact “atmospheric height” while maintaining other properties of this simulation.
- Atmospheric Pressure at Altitude** (Paltitude):
Paltitude [unit: kPa] = Psurface * exp(Pr * maltitude) [Pr may be -Pr, I don’t remember]
This post is obviously incomplete, but it’s been a while since I posted anything here, and I felt like I should go ahead and share what I’ve been up to.
A while back I produced a work of Modern Art with the software suite known as Factorio. This only needed minor editing but I was a very lazy girl. Today, I bring you… Everything Is Okay, a custom alarm to let you know that your world isn’t ending.
Decorations rattled from the boom of suddenly displaced air. A figure appeared in the hallway across from the study. Her eyes met a dragoness on a couch, looking back with a neutral expression. “Where am I? Are you a demon?”
“My home. And it depends on where you are from, summoner.. However, I do enjoy collecting lost souls.” She smirked, “You seem a little lost.” The dragon stood slowly, tasting the fear radiating from her visitor.
The figure held her ground as the dragoness approached, smile growing wider, “Want to make a deal, my dear?”
“What kind of a deal?”
Drabble is a form of extremely short storytelling, where you are limited to exactly 100 words.
I’ve spent a lot of time trying to answer certain questions in astronomy, where I just want a rough approximation for the purpose of a simulation, and don’t need an exact answer. These are some of the equations I’ve come up with.
Temperature (K) → Absolute Magnitude (visual):
Mv = 35.463 * exp(-0.000353 * T)
Roughly accurate between 2000-50000 Kelvin. Probably doesn’t continue accuracy at hotter temperatures.
Absolute Magnitude (visual) → Luminosity (solar luminosities):
Lsun = 100 * exp(-0.944 * Mv)
Accurate between 0-10 Mv. Probably continues accuracy relatively well.
Spectral (UBVRI) Filters:
Ultraviolet, Blue, Visual, Red, Infrared.
Objects are listed in different indexes:
U–V for the hottest objects (stellar remnants, galaxies), then B–V (the majority of stars), and R–I for the coolest (LTY “stars” and below).
B-V index (x) → Temperature (K):
T = -772.2x3 + 3152x2 – 6893x + 9500
Sorta accurate between 0-2. (This equation I am least comfortable with, and don’t plan to use.)
Main Sequence Luminosity/Mass Relation:
Lstar / Lsun = (Mstar / Msun)3.5
Yerkes Classes’ T/Mv Relations
These equations are shown as functions where x is temperature in Kelvin, and f(x) is absolute visual magnitude. Most are valid from 2400 K to a little bit past 30000 K, the exceptions are noted. For the hypergiants and white dwarfs, the range is within an elliptical region, of which these functions define the major axis; for all others, they are a center-point along a Yerkes classification.
f(x) = -8.9
f(x) = -0.00135x3 + 0.0233x2 + 0.0187x – 7.349
f(x) = 0.00329x3 – 0.0962x2 + 0.829x – 7.209
Bright Giants (II):
f(x) = 0.00557x3 – 0.166x2 + 1.505x – 6.816
f(x) = 0.0135x3 – 0.373x2 + 3.019x – 7.233
f(x) = -0.151x2 + 2.216x – 5.128 (4450-100000 K only)
f(x) = 0.00193x5 – 0.0615x4 + 0.742x3 – 4.257x2 + 12.439x – 12.996 (note: this one is the least accurate)
f(x) = 0.131x3 – 3.275x2 + 27.576x – 71.7 (3050-6000 K only)
White Dwarfs (VII):
f(x) = 0.489x + 10.01 (4450-30000 K only)