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Ukraine's 26th brigade hit 3 BM-21 Grad systems with 155mm artillery
Main Post: Ukraine's 26th brigade hit 3 BM-21 Grad systems with 155mm artillery
Top Comment:
That's an impressive crater.
Suggestion for DIY stacking systems: use 3 bins/buckets to start, not 2
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I started a new system to test out vermicomposting in my basement. I want to see how a small population of red wiggler's does down there before I bring my whole colony down there.
I have 3, square, 5-gallon buckets as the start of my system. The bottom most bucket is for leachate drainage--it has a ball valve with plastic tubing at the base so I can periodically drain it out without disturbing the system.
The next bucket has a 2" hole drilled in the bottom, with a vent in it. The vent is there to reduce worms going into the drain bin. This second bin has coconut husk, not coir, but coarsely chopped mulch.
The third bin has several smaller holes drilled into it to allow leachate to drain into the intermediate bin, get soaked up by the mulch, and then drain to the very bottom.
If/when the mulch at the bottom layer gets saturated, I can mix it into the bin with the worms in it, and add more mulch to that base.
The goal here is to prevent the issue I am having in my two bucket system--I have worms that like to go down into the grossness in the drainage to get access to the bacteria there, but they can't seem to get back up. By adding that middle layer with mulch, my worms will have access to some leachate if they want it, but that layer won't get gross because that layer has drainage.
Top Comment:
Thanks for sharing! Interesting idea. Keep us updated on whether this works as you intend.
What are some good rpg systems for 3 people (1 GM, 2 players)
Main Post:
Hi,
We're looking for a new system to try for our small home group and I'm wondering which systems work well for our amount of players.
We're all pretty experienced with a bunch of RPGs (Shadowrun, D&D, DSA, Burning Wheels, BitD, AW, Mouse Guard, Fate, ...) and looking to explore more.
So... any recommendations?
Top Comment: Honestly, I think Call of Cthulhu works great with a smaller group. Your decisions matter more, there's more opportunity to RP and combats are a LOT scarier when there's only one chance to pull you out of the fire...
ELI5: How do the 3 Japanese writing systems differ and why is it necessary to have all 3?
Main Post: ELI5: How do the 3 Japanese writing systems differ and why is it necessary to have all 3?
Top Comment: Is it "necessary" to have all three? It would certainly be possible to represent Japanese with just one set of symbols. They have three for historical reasons, not because it is "necessary". On the other hand, at this point, the current system is so deeply embedded in the culture (in books, signs, old letters, everywhere!) that it would be almost impossible to change.
Chaotic 3 (or more) Body Star Systems that Actually Exist
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Just finished the trilogy and I can't even describe how much I loved every bit of it. My background is in physics and I'd love to start a series of posts connecting to real-world science. I've got a simple one to start.
If you've looked into the Alpha Centauri system, you may have noticed that it's not actually a chaotic three-body system as described in the book. Don't worry, I don't think this takes away from the book overall; even Cixin Liu notes this:
For example, the initial inspiration for writing The Three-Body Problem came from a paper about the three-body problem in classical mechanics, which involves the motion of three bodies under mutual gravitational attraction and is unpredictable under current mathematics and physics. I read the paper and suddenly thought: what if the three bodies were three suns? How would intelligent life on one of the planets in such a system develop? This was a good science-fictional idea — based on solid science but also evocative of interesting stories. But to go back to real science, we have not, to date, discovered any trinary star systems in which the stars move in this chaotic manner.
What a lovely way to describe the approach of writing hard science fiction – but wait! While Alpha Centauri isn't truly the chaotic trinary star system described in the book, there are chaotic star systems containing three (or more) stars in the universe! I'd like to briefly discuss the real-world systems that would form the landscape of the Trisolaris story.
Multi-star systems can generally be classified as Hierarchical or Trapezia.
Hierarchical: A system with nested pairs of bodies. These are by far the most common systems and Alpha Centauri is such an example. Let's consider, why isn't the Alpha Centauri system chaotic? First, two of the stars (Alpha Centauri A and Alpha Centauri B) orbit each other, ranging from 11.2 AU to 35.6 AU; this can be thought of as a two-body system. However the third star (Alpha Centauri C, aka Proxima Centauri) is a whopping 13,000 AU away! Because of this distance, it's virtually impossible for C to pull on A differently than B and vice-versa. Therefore, it's simple enough to think of "AB" like a single body, and treat "AB" and "C" as its own two-body system. This is why Hierarchical systems are so stable: a pair of close bodies is a two-body system, and such a system can be treated as a single body of another two-body system.
Trapezia: These are the systems where the bodies are evenly spread out enough, have comparable masses, and therefore have strongly interacting orbits which result in chaotic behavior. The Trisolaran system is such an example of a Trapezium system. Naturally these systems are unstable, as it's possible for one of the bodies to be flung out or for bodies to crash into each other easily. Because of this, it's easier to find such a system in portions of the universe where stars are actively being created, such as gaseous nebulae.
Trisolaris was already unstable and on track to have the planet destroyed. However, it was able to stick around for a non-trivial amount of time. If the Trapezia systems are so rare and unstable, are there any real systems that actually are chaotic but have lasted a sufficiently long time for life to develop? One paper, The Maximum Age of Trapezium Systems, can help answer. They introduce the problem with:
Trapezia have been found in gaseous nebulae (Ambartsumian 1954 ; Sharpless 1954). Ambartsumian provided a catalog of 108 such systems. Their association with gaseous clouds added evidence that Trapezia are young. But there is a logical dilemma here. If one looks at young gaseous nebulae and sees Trapezium systems, that does not imply that all Trapezia are young. There are many apparent Trapezia listed in the catalogs of visual double or multiple stars that are not imbedded in gas clouds.
In fact, the paper finds that while they started with a catalog of 968 Trapezia systems, modern imaging techniques only left them with 14 true Trapezium systems. Based off these findings, they provide an upper limit to the age of these systems: 50 million years. Is that enough time for Trisolaran life to develop? Earth took 2.7-3.5 billion years to develop life, but we have no way of knowing if that's particularly long or average. Theoretical models propose that life could develop in as quickly as 10-17 million years. Additionally, life could develop before a system became chaotic, e.g. if the third body is introduced later. So far in the realm of unlikely, but possible!
Finally, here's the fun question. Where is the closest such chaotic Trapezium system? The Trapezium System paper above actually shows that the system which gave the name "Trapezium" doesn't actually have any such star systems:
Trapezium systems, of course, were named after the Trapezium in the Orion Nebula Cluster. The reported expansion (Strand 1957) of the Orion Nebula cluster proved to be spurious. Allen & Poveda (1974) showed from observations that no Trapezia in their sample of 33 systems showed any measurable expansion.
After filtering away all the false positives, the paper identifies ADS 719 as the closest known proper Trapezium – now known as the HD 5005 system which is contained in the IC 1590 Open Cluster. The good news is, this puts our real-world nearest Trisolarans* at a distance of 9600 light years!
*Note that the HD 5005 system is actually even more complicated; it's a 5-star system where AB and DE each form close-together binaries. Then, AB, C, and DE form a chaotic "approximate three-body" system. Technically then, the aliens here would be Pentasolarans!
Top Comment: "HD 5005 is a five-star system" sounds like a review on a movie poster
Reddit - Dive into anything
Main Post: Reddit - Dive into anything
3+ Systems & Games Compatibility List
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Appologies I can’t find on google or here what I’m looking for. Could someone please direct me to a the game and system compatibility list? All I remember is it was a google spreadsheet. Thank you so much!
Top Comment:
Here it is - https://docs.google.com/spreadsheets/d/1Vf7SIS7ecWa_J301h0mb2bxMWBMtKLvcpAFyaa5-LDc/edit#gid=580546752