I like to think I can have an amateur’s understanding of physics. For things like projectile motion, I feel pretty good. But when it comes to space-time waves:
CF researchers have developed a way to control the speed of pulses of light. Not only can they speed up a pulse of light and slow it down, they can also make it travel backward. UFC
What? I found this analogy from Brian Dunning, who puts out the excellent podcast Skeptoid (listen or read transcripts.)
Phase velocities are free to go faster than the speed of light, c, because they are conceptual, like a moire pattern from parallel fences you pass by.
Imagine you have a laser pointer that can paint a dot on the Moon from your back yard. (Caution: Do not look into that laser with your remaining eye.) If you sweep it quickly across the lunar surface the dot can appear to move across the regolith at greater than the speed of light, but the dot isn’t a thing so much as a concept, our name for what the light looks like. The actual photons that are flung to the Moon are moving at good old-fashioned c. Brian Dunning
Huh. If you have the chops for physics, check out “Optical space-time wave packets having arbitrary group velocities in free space” by Ayman F. Abouraddy in Nature Communications 10, Article number: 929 (2019). Open access (yay!) Yes, it’s taken me over a year to trip over the study. When you’ve absorbed the article, come back and explain it to me.
An unusual research project brought that quote from an old Bugs Bunny cartoon to mind.
Is it possible to recreate a smell out of history? The Odeuropa Project is tackling that quest, starting with 16th century odors. But what records preserve the necessary data?
They’re going to do it with artificial intelligence. The first step is to train machine learning software to recognize references of scents from historical texts and paintings. Researchers will feed the computer texts from seven languages and images of paintings to train the software… then the software will be able to scan thousands of documents and images to identify smell descriptions.NPR
Paintings? I suppose a painting of, say, a late 17th century London coffee house will include clues. But turning them into a useful file seems daunting. Written descriptions strike me as a more straightforward place to search for data, but then the words must be replaced by air-borne molecules.
Once information is found, recorded, and sorted, human beings replace the AI. “The team will then work with chemists and perfumers to recreate around 120 scents — with the plan to help museums integrate them into exhibits to create an immersive step into history.”
So Bugs’ vision of future smelevision won’t be turning up in your home. Three or four years from now, you’ll have to find a museum participating in the grand project. If I were you, I’d avoid sticking my head into whatever device delivers the smell of the mid-1800s Thames River.
Stuffed like my turkey
Gravy, cranberries, and pie
Cats now lick the plates
BTW, if you’re sleepy, don’t blame the bird.
Tryptophan is one of 20 naturally occurring amino acids—the building blocks of proteins. Because the body is unable to manufacture tryptophan on its own, it must be obtained from food protein. Turkey is a great source of this essential acid, but it is not unique: many meats and other protein products pack comparable amounts.
Tryptophan is used by the human body to make serotonin, but eating turkey does not translate to amplified serotonin production in the brain
It’s just a food coma. Ahhhh. Scientific American
On your way to an event? Perhaps against your better judgement, but just can’t say “no?” Here’s a quick and easy tool to gauge your risk.
The risk level is the estimated chance (0-100%) that at least 1 COVID-19 positive individual will be present at an event in a county, given the size of the event.Covid 19 Risk
Since the tool presents the risk by county, if you will see people arriving from other counties, I suggest you figure the risk for each “source.”
You can reduce the risk that one case becomes many by wearing a mask, distancing, and gathering outdoors in smaller groups.
I’m about to put my turkey in the oven for me, my spousal unit, dog and two cats. There’s no place like home. Hope to see you next year.