Tag: images

Drake equation correlations

Overall, the independence of the terms of the Drake equation is likely fairly strong. However, there are relevant size scales to consider.

  • Over multiple gigaparsec scales there can not be any correlations, not even artificially induced ones, because of limitations due to the expansion of the universe (unless there are super-early or FTL civilizations).
  • Over 100s of megaparsec scales the universe is fairly uniform, so any natural influences will be randomized beyond this scale.
  • Colonization waves in Brin’s model could have scales on the galactic cluster scale, but this is somewhat parameter dependent.
  • The nearest civilization can be expected around , where is the galactic volume. If we are considering parameters such that the number of civilizations per galaxy are low V needs to be increased and the density will go down significantly (by a factor of 100), leading to a modest jump in expected distance.
  • Panspermias, if they exist, will have an upper extent limited by escape from galaxies – they will tend to have galactic scales or smaller. The same is true for galactic habitable zones if they exist. Percolation colonization models are limited to galaxies (or even dense parts of galaxies) and would hence have scales in the kiloparsec range.
  • “Scars” due to gamma ray bursts and other energetic events are below kiloparsecs.
  • The lower limit of panspermias are due to being smaller than the panspermia, presumably at least in the parsec range. This is also the scale of close clusters of stars in percolation models.
  • Time-wise, the temporal correlation length is likely on the gigayear timescale, dominated by stellar processes or advanced civilization survival. The exception may be colonization waves modifying conditions radically.

Asperitas

that’s some rad-looking clouds

As the founder of the Cloud Appreciation Society, Gavin Pretor-Pinney, saw these submissions trickle in, he realized his group had collectively stumbled onto something interesting: A new type of cloud. This formation wasn’t listed in the International Cloud Atlas, published by the World Meteorological Organization since 1896. So Pretor-Pinney devised a name for this cloud — “Asperitas”, derived from “a passage in Virgil describing a roughened sea”. He’s been working for years to get it accepted into the next edition of the Atlas.

Medieval Fonts

Medieval script tells time, although usually not very precisely. Take for example the 3 major script families from the medieval period: Caroline minuscule, Pregothic script, and Littera textualis or Gothic script.

Despite the fact that these 3 families are relatively easy to distinguish and identify, they were used for extensive periods of time: Caroline from c. 800 to c. 1050, Pregothic from c. 1050 to c. 1250, and Gothic from c. 1250 to c. 1500. In other words, merely identifying the family of handwriting is not enough to pinpoint when precisely a book was made.

D&D maps

So here I’m collecting all my maps so you don’t have to dig through the whole archive of blog posts to find them. They are presented in reverse chronological order, starting with the most recent maps and then proceeding into older and older examples of my work. I’ve also included a legend of the majority of the mapping symbols used throughout these maps (well, mostly the overhead maps – the side-views are pretty much the same and/or self-evident I hope).