« September 8, 2021 | Main | September 10, 2021 »

September 9, 2021 Archives

Thursday, September 9, 2021

THE HAPPENING WORLD: The Metaverse—Second Coming for Second Life?

Posted at 13:06 Permalink

TRACKING WITH CLOSEUPS: Were the Boskops, Prehistoric Hominids, More Intelligent Than Modern Humans?

And if they were, and evolution selects for intelligence, what happened to them? Maybe they invented socialism, let technological development stagnate and be regulated out of existence, then ceased to breed when the cost of forming families and raising children became too high for the young.

Posted at 12:47 Permalink

CONTEXT: Moonfall—Do It Yourself Guide

There is a teaser trailer out for a movie scheduled for release in February 2022, Moonfall, which looks to be a particularly cheesy and absurd techno-disaster-thriller flick, even by the standards of the genre. See for yourself.

The premise is that the Moon has, for some reason, fallen out of its orbit and is closely approaching the Earth—in 2022. (I guess it really takes something to beat 2020 and 2021.) Anyway, as opposed to tidal disruption of the Moon when it crosses the Roche limit (which, for the Earth, is 6378 km), ocean tides scrubbing clean all the continents, etc., what seems to happen involves crashing cars, explosions, and for some screwball reason, the NASA space shuttle coming back from museums to fly again. How bad can it be? Well, the credits include Donald Sutherland.

Just how did the Moon lose enough orbital velocity to come close to the Earth? I'm not saying it's aliens, but from the trailer, that's the way to bet. And why would aliens expend enough energy to de-orbit the Moon to wreak havoc on the Earth rather than the more economical approach I used in Trek's End? I guess we'll have to wait and see which, for me, means until it comes around on Netflix.

Here, Scott Manley does the math on bringing the Moon down to Earth, and simulates the event in Universe Sandbox. For aspiring cosmic supervillains, he explains how, if you're patient, you can do it with half the delta-v by using a bi-elliptic transfer.

Posted at 12:20 Permalink

CONTINUITY: Hewlett-Packard 150A Oscilloscope Restoration: Part 3

With basic functionality restored, the focus turns to the inoperable second channel, a mystery thermistor, dodgy tubes, leaky capacitors, calibration, and the eternal confusion of RMS and peak-to-peak AC voltages. The behaviour of vacuum tube direct coupled and balanced amplifiers can be subtle, and even the slightest change can be puzzling.

Posted at 11:14 Permalink