Notes from a panel at Capricon 44, Chicago, Feb. 2, 2024. Any mistakes are mine. The panelists are not responsible for any errors here.
Bill Higgins, Henry Spencer
The OSIRIS-REx asteroid sampler has returned with a bounty of asteroid dust. Our panelists discuss what the findings have been so far, what is still to come, and what it all means.
There has been some media buzz that some objects found on the ocean floor are evidence of alien technology. However, the Harvard astronomer’s “alien spherules” are industrial pollutants. For technical details see:
Back in 2020 there was a report that Phosphine had been found in the atmosphere of Venus. Since Phosphine can be a sign of life that caused some excitement. I posted about this three times:
The last of these was in reference to Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine? At the time that seemed like the end of the story.
However, there have been a lot more observations since then and some re-re-analysis of the earlier work, leading to Phosphine Confirmed Deep Within Venus’ Atmosphere, A Possible Sign Of Life. I am looking forward to seeing the technical details.
Triangle-Wheeled Bike Gives New Meaning to ‘Tricycle’. The inventors
… went back to the drawing board to see if they could come up with a bike design featuring triangular wheels. They succeeded, and unlike the square-wheeled bike, these triangular wheels actually roll like round ones.
This is known as the Reuleaux triangle. I first ran across it in Poul Anderson’s 1963 SF story The Three Cornered Wheel, which I read sometime in high school (1964-68). A stranded spaceship crew needs to transport a heavy object over land. Unfortunately, the use of anything circular for mundane purposes is forbidden by the religion of the natives. However, the use of a curve of up to 1/3 of a circle is allowed for a sufficiently important cause. The young hero figures out that using such a “three cornered wheel” will solve the crew’s problem without offending the religious authorities.
Only harmonic spring and gravity central forces produce periodic motions.
Bertrand’s Theorem. I had to prove this as a homework problem in the fall of 1972, while taking a course in classical mechanics at Stanford. That was very satisfying.
Indian-American mathematician C R Rao awarded Nobel Prize equivalent in Statistics at 102
Rao was already famous among statisticians when I was working for my M.S. in that field back in 1975-76. Nice to see that he is getting the recognition he deserves, and that he is still around to enjoy it.
Why don’t moon photos show stars?. Specifically, why can’t we see the stars in the photographs of the Apollo Astronauts on the moon? As the article clearly explains, all of the pictures were taken during lunar daylight, during which the lunar surface is well illuminated by the sun. This completely washes out the light from the stars. If you made a long enough exposure to catch the stars, the lunar surface, the astronauts and their gear, and the lunar lander would be grossly overexposed. This would defeat the purpose of documenting human activity on the moon.
In fact, this issue was anticipated by Arthur C. Clarke in his classic science fiction novel A Fall of Moondust, first published in 1961, eight years before the first Apollo expedition landed on the moon. Continue reading
Highlights from Quantum Bullsh*t: How to Ruin Your Life with Advice from Quantum Physics, by Chris Ferrie
For decades I have been fascinated by 19th century celestial mechanics. This book is about one of my favorite stories from that field.
Highlights from The Hunt for Vulcan: . . . And How Albert Einstein Destroyed a Planet, Discovered Relativity, and Deciphered the Universe, by Thomas Levenson
I have known about Electron–positron annihilation for at least 52 years, from my course in Atomic and Nuclear Physics at Carleton College in the spring of 1970 if not before. The reaction is
e– + e+ → γ + γ
I had always assumed that the inverse reaction
γ + γ → e– + e+
was also possible because of time reversal symmetry. Apparently so had everyone else, but it has only recently been observed: Matter arises from light? We finally know the answer to this question!. Even now there is a caveat about “virtual” as opposed to “real” photons.
From Hilbert Space to Dilbert Space, and beyond 