[ThTh1] So, you may have seen the headlines:
Astronomers behind the most extensive search yet for alien life are investigating an intriguing radio wave emission that appears to have come from the direction of Proxima Centauri, the nearest star to the sun.
The narrow beam of radio waves was picked up during 30 hours of observations by the Parkes telescope in Australia in April and May last year, the Guardian understands. Analysis of the beam has been under way for some time and scientists have yet to identify a terrestrial culprit such as ground-based equipment or a passing satellite.
So, have we detected aliens? Well…probably not.
My friend Jason Wright goes into the details here and the Bad Astronomer tackles it here. I recommend both posts for a thorough evaluation (especially Jason’s as this is his wheelhouse) but I’ll summarize as best I can.
The Breakthrough Listen program looks for potential alien signals. It separates artificial signals from natural signals using the fact that artificial signals should be concentrated in a very narrow band of frequency and shift with the motion of the sky, rather than that of Earth. It has successfully detected a number of artificial signals. But all of those have been from human-made satellite or probes. In fact, human-made sources number in the millions. Breakthrough tries to use various techniques to separate those out.
Breakthrough Listen sometimes analyzes data taken in the course other scientific programs. In this particular case, the Parkes Observatory was studying Proxima Centauri, the nearest star to our own. Proxima Cen is small cool red dwarf that occasionally has massive flares, which makes it an interesting target to study in all wavelengths. It is also for this reason that Proxima Cen, despite having two planets, is though to be an unlikely location for extraterrestrial life. The frequent flares would presumably scour the planets of any possible life.
What happened here was that the team got a signal that can’t be easily ruled out as interference. That doesn’t mean it’s aliens. It’s most likely a form of interference hasn’t quite been able to identify and they are still working on it.
[ThTh2] This video nicely explains how the COVID-19 vaccine works and the efforts that have been going since the day it was discovered. I will add more thing. Assuming the Pfizer vaccine gets its full distribution of 100 million doses, that will mean 50 million people who are protected. That is roughly the same number of Americans who have gotten immunity by catching the virus, extrapolating from the number of deaths and assuming a 0.7% IFR. And the vaccine won’t kill 300,000 people and send several million to the hospital in getting to that figure. So much for herd immunity.
[ThTh3] Speaking of COVID, you may have heard of a new variant having emerged in the UK. Is this something to worry about? Will this make the vaccine useless? The answers are “maybe” and “probably not”. The concern is that this involves a mutation to the spike protein, which the new vaccines target. The current thinking is that this might lower the effectiveness of the vaccine a bit while increasing the infection rate, necessitating more uptake from the public in order to put the disease on its heels.
Mutations happen and we’ve long known it might be necessary to periodically update the vaccine. But updating it should be an even shorter process than developing it in the first place. This does, however, remind us that the herd immunity approach is — once again — a poor one. Because the more people are infected, the more likely variants are to emerge. And if the vaccine loses effectiveness, that means the immunity acquired by infection does too.
[ThTh4] Apparently, people have been telling stories about the Pleiades for 100,000 years.
[ThTh5] In theory, tides follow the orbit of the moon. In practice … less so.
If land didn't get in the way, ocean tides would be very simple: enormous bulges of water moving west with the Moon and Sun. Instead, land confines the tides, forcing them to have a range of complex frequencies
Credit: @NASAViz pic.twitter.com/YATqkhAnqE
— Dr. James O'Donoghue (@physicsJ) December 13, 2020
[ThTh6] One of the most enigmatic codes out there — the Zodiac killer’s 340 codes — has been solved.
[ThTh7] An app that stops nightmares? Nice.
[ThTh8] And we’re not done with vaccines. A malaria vaccine is on its way. And it could save hundreds of thousands of lives.
[ThTh9] And just because I can, here’s an old video describing how Eratosthenes measured the shape of the Earth. I showed this to my Astronomy 1 class this year. And the cool thing is we’re still doing this, finding indirect ways of measuring the shape of the Universe itself.
ThTh8: hopefully the new technology opens up a lot more vaccines.Report
ThTh9: Didn’t Eratosthenes measure the size rather than the shape? Sagan’s visual aid shows the experiment would work as well with a cylindrical Earth as a sphere. Or a toroid*, depending on what other assumptions you make about what circles what. But by Eratosthenes’s time the spherical shape was generally accepted by the educated folk.
* Topologists, the people who mistake coffee cups for donuts :^) I really enjoyed topology in graduate school, taught using the Moore Method.Report