Recently in TRACKING WITH CLOSEUPS

Saturday, October 30, 2021

Exploring Ant Nest Architecture with Molten Metal

Prof. Walter Tschinkel's book, Ant Architecture: The Wonder, Beauty, and Science of Underground Nests, published in June 2021, describes the techniques he has developed for casting ant nests and what he has learned about the various ways ants structure their subterranean habitats.

Posted at 12:21 Permalink

Friday, October 29, 2021

Supersonic Baseball: 1, Mayonnaise Jar: 0

Posted at 10:15 Permalink

Thursday, October 28, 2021

An Appreciation of Pure LISP

John McCarthy's 1960 paper, “Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I” [PDF, reproduction of original], which introduced the LISP programming system, was a stunning achievement in the history of computing. McCarthy proved that with only a minimal set of functions and linked lists, it was not only possible to evaluate any computable function (Turing completeness), but that there was no distinction between programs and data—programs could manipulate themselves as easily as they could items of data. In a sense,a large part of the history of programming languages in the six decades that followed was re-inventing concepts inherent in Lisp from its origin.

In this talk from 2019 Linux conference, Kristoffer Gronlund describes LISP, demonstrates how so few primitives can have such power, and describes how it has influenced programming languages and how we think about computing over the years.

Posted at 12:33 Permalink

Wednesday, October 27, 2021

Starship Mars Missions Before Refuelling on Mars

SpaceX's plans for an Earth-Mars transportation infrastructure assume the ability to refuel Starships on Mars with methane and oxygen propellant manufactured from resources on Mars (carbon dioxide and water, plus electricity generated from solar or nuclear power), a process called “in-situ resource utilisation” (ISRU). But first the propellant plant has to be delivered to Mars, so initial Starship missions will necessarily be one-way, at least until the plant they deliver has produced sufficient fuel to permit them to return. Marcus House looks at the logistics of this, including the mass budget for a solar powered propellant plant.

Posted at 13:22 Permalink

Tuesday, October 26, 2021

Origins of Photography: From Daguerrotype to Roll Film

Posted at 12:55 Permalink

Monday, October 25, 2021

Flying Ants in Slow Motion

These male (drone) ants are of genus Odontomachus (trap-jaw) and Aphaenogaster and were recorded taking off and flying at 1500 and 3200 frames per second,

Posted at 14:23 Permalink

Investigating the Apple M1 Pro and Max Chips in Detail

Here is the full AnandTech article, without clicky-breaks between sections, “Apple's M1 Pro, M1 Max SoCs Investigated”.

Posted at 13:17 Permalink

Sunday, October 24, 2021

Blue Field Entoptic Phenomenon—Seeing Blood Cells in the Retina

The really remarkable thing about the blue field entoptic phenomenon isn't that you can see the red blood cells moving, but that you don't see the blood vessels and blood in front of the retina all the time. This is the brain up to its old trick of “editing out” distracting information.

Posted at 14:38 Permalink

Saturday, October 23, 2021

Collecting and Curating Crayfish in Carolina

Posted at 12:52 Permalink

What Is This? Exploring a Mystery Hewlett-Packard Instrument From 1950

I was about to call this an “early Hewlett-Packard product”, but that wouldn't be correct. Hewlett-Packard was founded in 1939 and by 1943 already employed 200 people manufacturing a line of electronic test equipment sold to industry and the military. This indisputably is, however, an odd Hewlett-Packard product.

Posted at 10:44 Permalink

Friday, October 22, 2021

Piranha Solution

A mixture of around 3/4 concentrated sulfuric acid and 1/4 hydrogen peroxide (don't add too much peroxide or it may explode, which would be bad) is called “piranha solution”. It does the most remarkable things to organic material. It is used in semiconductor manufacturing to remove photoresist from silicon wafers.

Posted at 13:07 Permalink

Embryonic Development of the Alpine Newt

Posted at 11:08 Permalink

Wednesday, October 20, 2021

James Webb Space Telescope Deployment—“29 Days on the Edge”

Here are some statistics to ponder:

  • 50 major deployment events
  • 178 release mechanisms
  • 300 single-point failure items
  • Sun shield:
    • 140 release mechanisms
    • 70 hinge assemblies
    • 8 deployment motors
    • 400 pullies
    • 90 cables, totalling 400 metres in length

All of this has to work, or the James Webb Space Telescope, which has been under development for 25 years and cost US$10 billion, will be space junk. Positioned in an Earth-Sun L2 halo orbit, no repair mission will be possible.

Posted at 13:25 Permalink

Tuesday, October 19, 2021

Morley Cigarettes and More—Hollywood's Fake Brands

Posted at 12:59 Permalink

Monday, October 18, 2021

A Monolithic Schmidt-Cassegrain Telescope

A Schmidt-Cassegrain telescope has multiple optical elements: a spherical primary mirror, a hyperbolic secondary mirror, a Schmidt corrector plate (aspheric lens), and sometimes a field flattener lens to create a planar image. Could you make all of these out of one solid piece of glass?

Posted at 11:19 Permalink

Sunday, October 17, 2021

Orbiting Nothing—Lagrange Points and Halo Orbits

Posted at 12:14 Permalink

Friday, October 15, 2021

Prelude FLNG—600,000 Tonne Floating Liquefied Natural Gas Plant

Here is more about Prelude FLNG. It is 488 metres long, 74 metres high, and rises 105 metres above the water line. Unpowered, it is towed into position by oceangoing tugboats, then tethered to the sea floor by chains and connected to well head equipment by flexible pipes. It is designed to be able to ride out a category 5 cyclone, and has the ability to “weathervane” into the wind.

Posted at 12:47 Permalink

Thursday, October 14, 2021

Payout Mechanism from a Vintage Slot Machine

Posted at 13:55 Permalink

Wednesday, October 13, 2021

Destructive Interference: Cancelling Light

Where does the energy go?

Posted at 14:16 Permalink

Tuesday, October 12, 2021

Firefly Aerospace Factory and Test Site Tour

Posted at 12:12 Permalink