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Science & Space

The most popular blog posts about science & space on Hacker News. 2,038 posts.

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1292

Packing the world for longest lines of sight

I have a side project to find the longest line of sight on the planet 1 using a novel Total Viewshed algorithm . At a resolution of 3 arc-seconds (~92m x 92m), the planet contains around 4.5 billion elevation samples 2 . Now obviously we don’t need to calculate the visibility between literally every single one of…

1294

High Precision Mapping from Scratch

The fun of owning rural property is that knowing where your land actually starts and ends is a guess usually. Sure, you have a parcel description, and maybe even an online service with “official” GIS boundaries (for us here in New Brunswick, this is GeoNB ). However, since it’s in the middle of the forest, the odds of…

1312

Holography without Lasers: Hand-drawn Holograms (1999)

I've stumbled across a technique for drawing holograms directly upon a plastic plate by hand. It sounds impossible, but I've been sitting on the livingroom sofa making holographic images of floating polyhedra, words, 3D starfields, opaque objects, etc. No laser, no isolation table, no darkroom, no expensive film…