Tuesday, April 20, 2021

Lined Up to Land on a Taxiway: Air Canada Flight 759

“Where's this guy goin'? He's on the taxiway.”

Here is more about the incident. “Air Canada has stopped using flight number 759.”

Is “whoa” the most-misspelled four-letter word in the English language?

Posted at 13:02 Permalink

Monday, April 19, 2021

Bitcoin Miners Increasingly Supported by Transaction Fees

As Bitcoin has matured, the compensation (“reward”) paid to miners for solving a hash and publishing a new block of transactions on the blockchain has steadily fallen following the rule in the original design. The reward Rn for publishing block number n is:

Rn = BTC 50 / 2⌊(n + 1) / 210000)⌋

Thus, the first blocks to be mined received a reward of BTC 50 each, while at the present time (around block number 679750), compensation has fallen to BTC 6.25 per block.

For Bitcoin to be sustainable, the community of miners must continue to find the undertaking profitable. If it becomes a losing proposition, they'll abandon the task and Bitcoin transactions will not be verified and confirmed on a timely basis by a large and diverse enough community of miners to ensure the integrity of transactions.

The idea was that, over time, as the volume of Bitcoin transactions grows, transaction fees paid by users of the currency, while remaining affordable to them, would grow so that miners would continue to find it profitable to clear transactions even as their revenue from coining new Bitcoin continues to fall (eventually to zero, after all Bitcoin has been mined, around the year 2140).

Today I performed an analysis to see what progress is being made toward that goal, and the results are encouraging. I analysed blocks mined in the 24 hour period between 2021-04-18 12:08 UTC (block 679691) and 2021-04-19 12:00 UTC (block 679783), a total of 93 blocks, with a mean time of 15.5 minutes per block (compared to the goal of 10 minutes per block, but note that this period began on a Sunday). The current reward paid to miners for a block was BTC 6.25 for all blocks. When a miner publishes a block, in addition to this standard reward, they collect the transaction fees associated with all transactions they include in the block—the transaction fee is set by users who submit transactions, and miners generally choose the transactions which, based upon their length in bytes and the fee offered, will generate the most revenue for them. Transaction fees for blocks during this period varied from a minimum of zero (two blocks, 679774 and 679779, contained no transactions and thus earned their miners no additional income) to a maximum of BTC 2.864 (block 679703), with a mean value of BTC 1.828.

Thus, for this 24 hour period, transaction fees accounted for 22.6% of the total reward of BTC 751.27 earned by miners, with BTC 581.25 due to the standard reward for mining a block. While transaction fees still account for less than a quarter of miners' revenue, if Bitcoin continues to become a mainstream mechanism for transferring funds and transaction volume grows apace, it seems plausible that transaction fees will eventually provide the majority of income to miners, which will motivate them to continue their essential services as difficulty increases and block rewards decline.

Posted at 19:41 Permalink

Sunday, April 18, 2021

Pilling the Cat

Next comes the realist phase (“After all, from a purely geometrical point of view a cat is only a tube with a door at the top.”).

— Terry Pratchett, The Unalduterated Cat

Posted at 11:27 Permalink

Saturday, April 17, 2021

Flip Clocks: the Non-Digital “Digital” Clock

The way they get the hour to flip exactly when the seconds go from 59 to 00 while allowing sloppy manufacturing and assembly tolerances is very clever.

Posted at 15:42 Permalink

Friday, April 16, 2021

What Shall We Call the Hill?

Posted at 16:41 Permalink

Thursday, April 15, 2021

The Wolfram Physics Project: One Year Update

The linked article, “The Wolfram Physics Project: A One-Year Update”, is a long read (13,179 words), but well worth the investment of time. What Stephen Wolfram and his collaborators are attempting is breathtaking in its ambition and, if successful, profound in its implications for our understanding of the fundamentals of physics and perhaps much more.

I've long suspected that our “fundamental theories” such as quantum mechanics and general relativity were effective theories describing emergent phenomena from a much simpler, very different, and in all likelihood discrete underlying substrate, just as the Navier-Stokes equations of fluid mechanics describe behaviour which is entirely the consequence of electromagnetic interactions between molecules at a lower level, which could never be discovered by elaborating models of the emergent phenomenon. The Wolfram Physics Project is exploring very simple models which, they have discovered, manifest emergent phenomena which seem to exhibit properties like relativity and quantum mechanics, providing encouragement they're on the right track.

A vast collection of on-line resources is available at the Wolfram Physics Project Web site, and the book, A Project to Find the Fundamental Theory of Physics, is now available in a Kindle edition which is free for Kindle Unlimited subscribers.

In the article, I found the brief discussion of the possible applicability of multiway systems to economics fascinating.

A bit like in the natural selection case, the potential idea is to think about in effect modeling every individual event or “transaction” in an economy. The causal graph then gives some kind of generalized supply chain. But what is the effect of all those transactions? The important point is that there’s almost inevitably lots of computational irreducibility. Or, in other words, much like in the Second Law of Thermodynamics, the transactions rapidly start to not be “unwindable” by a computationally bounded agent, but have robust overall “equilibrium” properties, that in the economic case might represent “meaningful value”—so that the robustness of the notion of monetary value might correspond to the robustness with which thermodynamic systems can be characterized as having certain amounts of heat.

This is similar to what I (reluctantly) called “Quantum Economics” in my 1988 paper, “The New Technological Corporation”.

We construct aggregates to approximate the behaviour of large numbers of discrete interactions. Sometimes they are useful, as in thermodynamics. Often they aren't, as with most macroeconometric measures. Wheeler suspects that all our laws of physics describe approximate behaviour of aggregates of observations; that the fundamental quantum event is all that really exists. Most of physics does not attempt to understand why these quantum events occur but simply describes the aggregate behaviour of large numbers of events. As we begin to understand the low-level mechanisms, we will get to the true physics beneath the aggregates. Similarly, in economics we try to predict behaviour of aggregates of individual transactions. Only the transactions are real; all the rest is the work of man. One may not be able to understand what drives the transactions by theorising based upon aggregates.

Parallels exist between markets and quantum mechanics. The electron has no position or momentum until you measure it. When you measure its position, you disturb it, forgoing accuracy in measuring the momentum. A share of General Motors has no price until a buyer and seller exchange it, a discrete event. This transaction/measurement affects the price of subsequent transactions. Prices are undefined until a transaction occurs, whether the purchase of a loaf of bread or the takeover of RCA by GE. Prices in a large liquid market can be predicted quite well since the effect of a single transaction is minuscule; prices in blockbuster transactions can barely be predicted at all. Similarly, you can predict interference fringes to many decimal places but which detector an individual electron will trigger in a dual slit interference experiment is unknowable in principle.

Just as Wolfram argues may be the case for physics, generations of economists have been struggling with effective theories based upon aggregates rather than getting down to the individual transactions, which is the bottom-level reality (what Wolfram calls the “machine code”) that their aggregates and abstractions will never discover.

Posted at 13:12 Permalink

Wednesday, April 14, 2021

N1-methylpseudouridine (m1Ψ) in COVID-19 Messenger RNA Vaccines

The paper is “Modifications in an Emergency: The Role of N1-Methylpseudouridine in COVID-19 Vaccines”, also available as PDF.

Here is background on pseudouridine and its appearance in various forms of RNA. It has been found in all three domains of life.

Posted at 09:52 Permalink

Tuesday, April 13, 2021

How Many Ways Can Circles Overlap?

Posted at 19:06 Permalink

Monday, April 12, 2021

SpaceX’s “Wet” Fleet Gives Up on Catching Falling Fairings

Posted at 12:17 Permalink

Saturday, April 10, 2021

The Great Olive Poisoning of 1919

Posted at 14:56 Permalink

Friday, April 9, 2021

Close Encounter above Siberia

Posted at 14:33 Permalink

Thursday, April 8, 2021


Here is more about dimethylmercury. Absorption of as little as 0.1 millilitre can be fatal, and the liquid can permeate normal laboratory and surgical gloves within 15 seconds.

Posted at 14:12 Permalink

Tuesday, April 6, 2021

Vacuum Tube Computer — Adding Skip to the Instruction Register

The skip logic simply forces an instruction of all ones into the instruction register when the SKIP signal is asserted. This is done with four OR gates with cathode follower buffered outputs to drive the instruction register flip flops. The OR gates are built from semiconductor diodes, which is fair enough since “diode OR” has been used in electronic computer logic circuitry from the very beginning: ENIAC used 7200 “crystal diodes” (or “crystal rectifiers”) as they were called at the time.

Posted at 13:38 Permalink

Photosynthesis from Infrared Emission by Deep-Sea Hydrothermal Vents

The paper is “An obligately photosynthetic bacterial anaerobefrom a deep-sea hydrothermal vent” [PDF]. Abstract:

The abundance of life on Earth is almost entirely due to biological photosynthesis, which depends on light energy. The source of light in natural habitats has heretofore been thought to be the sun, thus restricting photosynthesis to solar photic environments on the surface of the Earth. If photosynthesis could take place in geothermally illuminated environments, it would increase the diversity of photosynthetic habitats both on Earth and on other worlds that have been proposed to possibly harbor life. Green sulfur bacteria are anaerobes that require light for growth by the oxidation of sulfur compounds to reduce CO2 to organic carbon, and are capable of photosynthetic growth at extremely low light intensities. We describe the isolation and cultivation of a previously unknown green sulfur bacterial species from a deep-sea hydrothermal vent, where the only source of light is geothermal radiation that includes wavelengths absorbed by photosynthetic pigments of this organism.

Posted at 10:44 Permalink

Monday, April 5, 2021

The Rise and Fall of the CIA's A-12 Spy Plane

The A-12 design, of course, went on to spawn the much more successful SR-71, although neither was ever used for the mission for which they were designed: overflight reconnaissance of the Soviet Union and Red China.

Posted at 12:25 Permalink

Sunday, April 4, 2021

The Future of Heat Pumps Is Underground

I had not heard of heat pump clothes dryers—that sounds like a tremendous idea, also reversible heat pump/air conditioners for electric vehicles.

Posted at 15:12 Permalink

Friday, April 2, 2021

How (and Why) to Raise e to the Power of a Matrix

Posted at 14:26 Permalink

Brian Keating: Searching for Lorentz Invariance Violation in the Cosmic Background Radiation

Posted at 11:50 Permalink

Thursday, April 1, 2021

The Clever Mechanism in Your Drink Carton

Posted at 11:14 Permalink

Wednesday, March 31, 2021

The Magnetic Worm Mystery

Posted at 15:05 Permalink