Nikolai Lofving Hersfeldt

Habitable Zone Charts

Working on some updates to Part IVc and I liked how these hab zone charts came out so I figured I'd preview them. As a quick key:

Dry (high albedo): inner limit for marginal habitability with almost no surface water and a questionably plausible albedo of 0.8

Dry (low albedo): as above with more reasonable albedo of 0.2

Slow Rotation: inner limit for planets with slow or fully tidal-locked rotation

Recent Venus: based on the (questionable) assumption that Venus was ...

Hurried Thoughts: Late Tidal-Locking Planets

Another short one on a concept I came across recently

Earth at 0.4 eccentricity (and no tilt)

Starting to look funky

Earth with 0.3 eccentricity (and no tilt)

Weirdly normal-looking isn't it

Earth with 0.2 eccentricity (and no tilt)

Climate Explorations: Day Length

Not a tuesday like usual, but wanted to get this one out before the blackout a lot of subreddits are doing next week

Turns out there's some issue with the 324x day run outputs (the days are much longer than they should be; not sure yet if this is an input issue on my end or a timekeeping issue inside exoplasim) so I left it out of this post and I'll probably do a set of runs with very long days another time.

Earth with 0.1 eccentricity (and no obliquity)

Now that exoplasim supports higher eccentricity I'm running my set of them and redid this one even though it doesn't seem to have come out much different.

I did complete a 324x day run but I need to make an adjusted koppenpasta script for it because the warm and cool parts of the year don't necessarily fall on the same season every year. Writing on the day length climate exploration post is underway

Incomplete run with 360x day length

This one crashed repeatedly it reached about 8 C; not sure why, the max temp only got up to around 30 C. I don't think I'll run it any further, though, because on further thought I think for purposes of this day length post it might be more interesting to see a case where day and year length aren't so closely synchronized (which produces some odd heating patterns that are variable by longitude as well as latitude; you can see the particularly cool areas over canada and east greenland where th...

Hurried Thoughts: Time Dilation Loop

Something new I thought I'd try every now and then; taking a concept that doesn't quite fit in any existing post or deserves a bit more highlighting and running with it for a little bit, might help break up the time between the big posts.

Update to Part IVb

This is perhaps the most substantial of these updates I'll be doing; I was never quite happy with how sparse the list of surfaces felt before and now it's a lot closer to what I originally intended. As usual the alterations page includes some highlights https://worldbuildingpasta.blogspot.com/p/alterations-to-existing-posts.html but really basically everything up to the "alien ...

Earth at 30x day length

Earth with 10x day length

green

Climate experiment outputs

I'll link this on the blog somewhere soon, but here's a folder with the netcdf outputs from the previous climate exploration posts, and I'll add to it as I make future posts. To keep the filesize down, I've removed a lot of the atmospheric data, but it still includes things like surface temperature, precipitation, snowfall, near-surface winds, total cloud cover, etc; i.e., enough to reproduce the climate maps and other figures I put on the blog.

Earth with 2x day length

Earth with 5x Day Length

If you want a rainforest world, this looks like it'd do it.

The 2x day length run borked while I was out of town, so I'll restart that, and I think I said I'd do 4x before but forgot I switched to 5x because it works better with how exoplasim stores data.

Earth with 3-hour days (properly this time)

Finally got this to balance at the right temperature; didn't take much more CO2 (6400 ppm), just tweaking the initial conditions to warm up faster before the big glaciers can set in. Exoplasim does not like rotation this fast, most of the run crawled along at 10-minute timesteps, but we got there in the end.

I'll be moving on to longer days now; current plan is 2x, 4x, 10x, 30x, and 360x day length (exoplasim doesn't distinguish sidereal and synodic days btw, it treats them as being eq...

Geology and Landforms: Constructing Global Terrain

Finally worked through this one, though it's still a bit of a work in progress; there's still a lot of tweaks and extras I want to investigate, but given how long it's been I figured I'd put out this tutorial on the core process now and update it with any new discoveries later.

ProjectionPasta

A little bit of software I put together for use in a couple future posts, for reprojecting maps between different aspects and projections. Not quite as user-friendly as something like G.Projector, but it has two key advantages:

1, It can take any of the supported projections at any aspect (orientation of the map relative to the globe) as either input or output.

2, It will preserve the color mode of the input, which is useful for stuff like 16-bit greyscale heightmaps.

T85 Experiments

A couple experiments with ExoPlaSim at t85 resolution (128 by 256 cells). The first is one for Earth, done by a friend at cartographer's guild, which shows a somewhat interesting mix of improvements and issues compared to T42 which I usually run at. The second is a T85 run for Teacup Ae which came out a tad warmer than I wanted but should help as input into the terrain generation process.

Collection of climate maps across the Phanerozoic

I recently ran across this paper https://www.nature.com/articles/s41597-022-01490-4 and realized I could pretty easily tweak my koppenpasta script to extract climate maps from their dataset. This folder contains the resulting maps, both in the Koppen-Geiger system and my approximation of the Holdridge system, named by their age in millions of years--the whole set covers the last 540 million years in 10-...

Simulating Star Evolution with Starpasta

For some reason patreon isn't properly embedding the link so here it is:

https://worldbuildingpasta.blogspot.com/2022/11/an-apple-pie-from-scratch-part-ii.html

Earth with 3-hour days (not final)

This is the latest output before I shut down the model for winter. You can see how severely the poleward heat transport has been affected, with the big ice caps cooling the whole planet; the global average temp here is 5 C despite over 5000 ppm CO2. The attached maps are surface winds in january and july, respectively, in m/s (the weird caption is just how panoply works these out, I usually replace that for the final posts).

General Progress Update

Because it's been quite a while since the last post in the main series, I figure a general update on how everything's going might be nice:

1, The next major post in the main "apple pie from scratch" series is going to be on making topographical maps, and has been taking a while largely because I thought it would be a great idea to once again find an obscure bit of research software with limited documentation and try to get that working. The good news is that it does actually work, but ...

Earth with 6-hour days

Climate Explorations: Obliquity

Earth with 12-hour days

It turns out removing the "fixedorbit=True" parameter does not actually allow for simulating high eccentricity, it just makes the model ignore the orbital parameters and run with Earth's orbit and rotation. I've made the dev aware of this, but in the meantime I'll run models with different day lengths instead (given that the model doesn't like switching day lengths and so each of these models has to be run from the start, it might take a little bit, but maybe not *that* long if, as appears to...

Earth at 35 and 40 Obliquity

Ran these two as quick extras to explore the rather stark transition between 30 and 45 degrees in more detail before I write up the obliquity post.

Incidentally, couple of quick tips:

-The "fixedorbit=True" parameter seems to cause crashes when eccentricity is over 0.1.

-It also seems like restarting from a model at one rotation period and changing to another rotation period can cause crashes as well, though I need to test that a bit more.

Climate Explorations Supplement

This is just  short supplement explaining the collection of scripts I use for automating the process of running ExoPlaSim models.

Earth at 0.1 eccentricity

This and all the other eccentricity models have zero obliquity. Eventually I want to do some tests with combined eccentricity and obliquity, but it's a ways down the list for now.

Earth at 15, 5, and 0 Obliquity

These all ran pretty quick so here they all are at once. The last one shouldn't have any seasonal zones, but because my automated process ran with the default settings, it shows a couple along borderline cells due to minor random variations.

That's the last of the obliquity models but I won't get home to look at the data until August. In the meantime, it'll move on to modelling different eccentricities, and I should have a quick overview of the code behind all this by the end of the mon...