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October 8, 2021 Archives

Friday, October 8, 2021

THE HAPPENING WORLD: Elon Musk at the 2021 Tesla Annual Shareholder Meeting

“Over time, you'll see all manufacturers will make electric vehicles, and eventually all manufacturers will make autonomous vehicles. Tesla is open to licensing autonomy.

“… you can recycle battery materials. You can think of batteries as essentially high grade ore. So you can get your lithium and your nickel … from rocks or from batteries. It's much better to get them from batteries.”

Posted at 14:52 Permalink

CONTEXT: “Slowed Canonical Progress in Large Fields of Science”


In many academic fields, the number of papers published each year has increased significantly over time. Policy measures aim to increase the quantity of scientists, research funding, and scientific output, which is measured by the number of papers produced. These quantitative metrics determine the career trajectories of scholars and evaluations of academic departments, institutions, and nations. Whether and how these increases in the numbers of scientists and papers translate into advances in knowledge is unclear, however. Here, we first lay out a theoretical argument for why too many papers published each year in a field can lead to stagnation rather than advance. The deluge of new papers may deprive reviewers and readers the cognitive slack required to fully recognize and understand novel ideas. Competition among many new ideas may prevent the gradual accumulation of focused attention on a promising new idea. Then, we show data supporting the predictions of this theory. When the number of papers published per year in a scientific field grows large, citations flow disproportionately to already well-cited papers; the list of most-cited papers ossifies; new papers are unlikely to ever become highly cited, and when they do, it is not through a gradual, cumulative process of attention gathering; and newly published papers become unlikely to disrupt existing work. These findings suggest that the progress of large scientific fields may be slowed, trapped in existing canon. Policy measures shifting how scientific work is produced, disseminated, consumed, and rewarded may be called for to push fields into new, more fertile areas of study.

Here is the full paper, “Slowed canonical progress in large fields of science”. I repeat my frequent observation, “Once Pareto gets into your head, you'll never get him out.”

Posted at 14:06 Permalink

CONTINUITY: How Photolithography Works—Part 3: Photoresist

Photoresist is the “secret sauce” of microelectronics. It is a chemical coating which, applied to a silicon wafer, is rendered soluble or insoluble by exposure to light. Post-exposure, the soluble part is washed away, leaving a mask which protects portions of the chip not to be affected by the next processing step. This sounds simple, but achieving nanometre resolution and avoiding optical distortion are formidable challenges which have been surmounted as device geometries shrink.

Posted at 13:06 Permalink

TRACKING WITH CLOSEUPS: “Never Mind”—“Gamma Ray Burst” From Remote Galaxy Turns Out To Be Flash From Space Junk

Detection of an apparent gamma ray burst in the act of occurring in a galaxy at redshift 11, indicating we are observing it as it was just 420 million years after the big bang was reported in the paper “A possible bright ultraviolet flash from a galaxy at redshift z ~ 11” in December 2020. “Not so fast” responded other astronomers, in the paper “A more probable explanation for a continuum flash in the direction of a redshift ≈ 11 galaxy” and elsewhere, pointing out the extreme improbability of such an observation and the far more likely explanation that it was a transient due to reflection from an orbiting satellite or space junk. Now the case has been closed with the publication of “GN-z11-flash was a signal from a man-made satellite not a gamma-ray burst at redshift 11” which identifies the flash as a glint of sunlight from a derelict Breeze-M upper stage from a Russian Proton rocket in a highly elliptical orbit.

Posted at 12:14 Permalink

CONTINUITY: Apollo Spacecraft S Band Communication System, Part 2

Communications from the Apollo spacecraft to ground stations were via an S band microwave link with a radiated power of 11.6 watts. The signal sent to the antenna was produced by the transponder unit and amplified by a traveling wave tube. This episode digs into the radio frequency (RF) power amplifier, explains its complicated system of relays providing redundancy, and describes how a traveling wave tube works and why they remain in use on contemporary spacecraft.

Posted at 11:44 Permalink