Another edition of Cheese Ends.
Get your bootleg provolone and swiss right here.
DARPA, the Defense Agency that brought you the internet years ago, is asking for proposals to demonstrate a thermal rocket in space.
This is potentially big news.
Chemical rockets produce thrust by hot gases that are created via combustion. Nuclear thermal rockets do something similar in that they take a gas and run it over a nuclear pile and heat it up enormously. The expansion forces it out the back end of the rocket. But NTRs are 2-5 times as efficient as chemical means.
Of course, none of them are as efficient as ion thrusters where the thrust gas is forced out via a magnetic field. Why not use them instead? The power requirements are enormous. So, until that happy time we can a fusion power plant into space, chemical and nuclear rockets are the only game in town. Of course, if we had a fusion power plant we could shoot into space, we could use a Direct Fusion Drive . DFDs probably rate their own column.
The US actually had an NTR program called the NERVA. It was quite successful in achieving its goals but it was cut between atomic nervousness and expense. DARPA getting into the game could be very interesting.
A study in Microbiome describes what absolutely no one foresaw: fecal transplants from young to elderly mice reversed some age related disorders.
This is pretty exciting, too.
The researchers were trying to tease out the role of gut microbes in aging. This association has been known for a bit but until now (to my knowledge, anyway) nobody has tried this experiment.
If I were so inclined, the SF story almost writes itself. You could go Hunger Games on this where aging power mad tyrants scour the youth for their intestinal flora. Or, even go economic: young donor shops his product around to find the right bidder. The possibilities are endless.
Plastic is hard to recycle. It’s hard to break down. It’s hard to reuse. Often, it’s difficult to dissolve it sufficiently to actually use it to make new plastic. Instead, the material is reshaped and used for inferior purposes—downcycling—and those products are often a dead end as well.
Biological systems recycle most things pretty readily using enzymes: chemicals that lower the required energy and bring within the temperature, pressure, and energy tolerances of living systems. We don’t break sugars down by heating them up and combusting them. We use enzymes to break them down at room temperature and pressure. Not having a couple of million years to figure out these new fangled plastic polymers, living organisms haven’t managed to crack them. Which is why our plastic milk cartons remain plastic in landfills instead of being eaten by bacteria.
The researchers in this study used a machine learning mechanism to find a set of enzymes that could quickly and efficiently take polymerized plastic and turn it back into usable raw material—what they call virgin plastic. Then, they introduced mutations into bacteria to use these hydrolases.
At least, that’s what I think they did. Much of the article is behind a paywall. So, I’m not sure if they induced a living organism to produce the enzyme or produced the enzyme themselves. But they were able to almost entirely degrade a PET water bottle in a week. Since these same water bottles circulate in the Pacific Ocean for years, that’s a win.
The article calls this “controversial” but I’m not so sure. Sabine Hossenfelder talked about this on her YouTube channel a while back. How controversial is it when a reputable scientist takes it to task on YouTube?
The Cosmological Principle is the presumption that on the largest scale the universe is pretty much the same on average. A corollary of this is the presumption that scientific principles and models should function the same regardless of locale. Campbell talked about this in one of his lectures when he mentioned the Apollo project. The depth of dust to be found on the Moon could not be determined without testing it. Yet, the amount of energy and thrust required was known before we got there. Differences across the universe must be explained in some way. The simplest approach is to say everywhere is the same. If everywhere is the same, then the same physical laws must apply.
Yet, there have been a number of observations that suggest the universe is decidedly not uniform on the largest scales. There are significant mass and energy imbalances in one direction over another.
There are some interesting problems that arise in the theories of the origin of the universe if the Cosmological Principle fails. Why isn’t the universe uniform? What would cause it? Theories abound.
There are at least two ice moons in our solar system that are thought to have internal oceans: Enceladus and Europa. In addition, Callisto and Ganymede might have oceans but buried under rock. All four are possible candidates for life if the oceans are liquid, not too chemically salty, and stable.
(Lately, I’ve been seeing Titan on the list of possible moons with life but I don’t see it. Life in liquid methane seas where the temperature hovers around -179C? You can use the word extremophile until you’re blue in the face but nothing on earth remotely compares to it. Antarctica is a tropical beach by comparison. There might be life there but it’s not going to resemble earth life in the slightest.)
These experiments have been trying to figure out the limits to where water will remain liquid. The chemical constraints and stability are a different matter and require further research.
This one came across my desk describing the operations of marriage forms within different economic mechanism. Unlike SF, this article used real marriage systems: the polygamous Mosuo people in China. This is not your standard one man, many women model that we’ve seen before. Instead, this is referred to as a “walking marriage” where men have no parental or economic responsibility whatsoever. Property is owned solely by the women.
It also described the polyandrous Jat people in Uttar Pradesh, where brothers share the same wife. This was presented as, essentially, a tax dodge. If three brothers married three women, there would be tax on three households. But of three brothers marry a single woman, there is only one household.
Of course, all of this denies the role of love. Love would come into this system as a disaster—much like the whole courtly love problem in the arranged marriages of the European nobility. But it comes, just the same.
That’s it for now.