The thing is, at such an early time in human (pre-)history, they did not have standardized number systems. This led to the very long ages of kings that we see in the Sumerian King List. A few details on how this happened… 🧵/1

https://twitter.com/4biddntruth/status/1933792744264052975

2/Today, most cultures in the world use base-10, and we use it for every digit in a number. The first digit is ones. The second is 10s. The third is 10x10s. The fourth is 10x10x10s, and so on.

In early Mesopotamian number systems, they did not use the same base for each digit. This example uses ones, then sixes, then 10x6s, then 3x10x6s.

I ran into an interesting story, and since I have much time on this cruise I will write it as a thread.

Teaser: The US owes its ownership of Alaska to one of “the Eight Beauties of Ancient China,” the concubine Chen Yuanyuan from the 1600s.

Here is the tale…
🧵 /1

shine.cn/feature/art-cu…

2/ The first part of this story was likely embellished during the Qing dynasty but it is based in truth. When the Ming dynasty fell in the 1640s, a ruthless general of the peasant rebels, Liu Zongmin, took the concubine Chen Yuanyuan hostage and treated her abusively. Her lover (or husband), Ming general Wu Sangui, was of course humiliated and enraged!

Well, Wu Sangui was the general defending the Shanhai Pass at the eastern end of the Great Wall, responsible for keeping out the barbarian Manchu.

1/ Let’s walk through a mining competition cycle. The students take their robots to the judge station for inspection and weigh-in. (More points awarded for lower-mass robots.)
2/ They set their robots on the forklift platform to lift into the arena.

@bobster190 @DJSnM @WilliamShatner The paper has all the citations to other work inside it. I linked the paper because it wouldn’t make sense to duplicate that in a tweet. The paper wasn’t about Pluto. It was only about asteroids. We wrote a second paper that discusses Pluto and I think answers your objections. /1 @bobster190 @DJSnM @WilliamShatner 2/ That 2nd paper is here (no paywall so it is accessible):

It does discuss the arguments surrounding the IAU’s vote in 2006. I think we did a much better and more complete review of the issues than any other publication on the topic. Most other papers…sciencedirect.com/science/articl…

Here is something that hints strongly at how human scientists and engineers are already doomed by AI. 🧵

I noticed this tonight while using Grok for technical research. I asked it a complex question and Grok understood it completely and gave a sophisticated and highly believable answer, but when I asked for specific references so I can write it into a paper for a journal, none of the references Grok provided exactly support the answer it gave me. Instead, they hint at something deeper.

In this case, I am quantifying the loss of signal margin in a Moon-Earth communications link as a function of how many times you landed near the communication system so the rocket plume sandblasted the electronics' thermal coatings, causing them to operate hotter than designed. There is a real cost to sandblasting your hardware on the Moon, and I am trying to quantify it.

Grok gave me many quantified effects, including that the frequency oscillator will drift about 10 to 50 ppm per deg C of temperature rise outside its operating range and that the Signal to Noise Ratio of the overall communications link will drop about ~0.1–0.5 dB for small drifts (<10 kHz) in particular modulation schemes. This is a great result that I can use to quantify sandblasting damage on the Moon, and the result is totally plausible, but it doesn't appear in ANY reference that Grok provided. Nothing discusses this.

So I suspect Grok actually derived that relationship itself during the LLM training. I think the relationship is probably correct, because the many references hint around the edges of this relationship in the right magnitude. I think Grok noticed the patterns of many performance metrics including temperature, input power and frequency, outputs, etc., for many devices and how they are connected in typical systems, and it stored as a higher-level symbol the result that you get 10 to 50 ppm per deg C performance loss. I think it solved that during training as it sought the higher-order symbols to store everything it had learned. IOW, its learning process included a heckuva lot of valid inference on these technical issues, and it now knows more about the performance of communications equipment than even the published literature knows.

I asked Grok if this is true, and it says it is correct (screenshots).

/1
2/ I then asked Grok to derive this relationship the same way it probably did during the LLM training, and it did. So now, if I want to use this key result in my paper, I have to use the many references that Grok used when it derived the relationship, and I have to show the derivation explicitly in the paper, or I can't publish it per the rules of scientific publishing (which of course were created in the days before reliable AI, and we still don't have totally reliable AI, but we can see it is coming fast).

I think it’s likely the Outer Space Treaty will be voided within the next few decades as nations will claim (effectively) national territory on the Moon and Mars.

Here’s why I think this…

/1 2/
The OST is part of the International Rules-Based Order that emerged post-WW2. The IRBO was originally multipolar with the US-led NATO and Soviet-led Warsaw Pact. The collapse of the latter left the US as the main power wanting to keep the IRBO. China/the CCP hates this.
theguardian.com/world/2023/oct…

I’d like to reemphasize this. The dust you see is not settling. It is still going uphill when it flies over the horizon and out of view. It is like a rocket that has curved below the horizon but is still climbing. If you get this, it makes sense why it clears the view so fast. /1 2/ It has so much grandeur when your mind can see it for what it is. It is not a humble cloud sinking to the ground. It is a vast, high energy phenomenon covering hundreds of kilometers in just a few seconds. In the vacuum of space nothing impedes its flight.

This is superb! Will be a treasure for quantifying plume-surface interactions during lunar landing. There are some things I don't understand yet and will take a while to unpack. (Note: I'm not supporting the mission so this is just my private musing.) 🧵/1

https://twitter.com/Firefly_Space/status/1896980472304910772

2/ I don't understand three things about the shadows.
First, there is a huge upward flow up the centerline. The plume itself should be clear and invisible, since it cools as it leave the engine and without an atmosphere to collimate it the shock structures in the plume are...

One time testing the Space Shuttle landing strip at White Sands, NM, the thought of this happening really scared me. We had just flown from Florida to Holloman Air Force Base in NM, which is 1.25 km above sea level. I asked the pilots about the barometric altimeter setting… 🧵/1

https://twitter.com/johncc2014/status/1887516493702705326

2/ because “0 feet” altitude above the runway in New Mexico is a lot lower barometric pressure than 0 feet at Cape Canaveral where we took off. The pilots explained how it is set whenever they are at a new airport. I was just wondering and thought no more of it till that night.

Great question. I don’t think the Moon can have solid sheets or lenses of ice like the Earth and Mars have. The absence of an atmosphere means everything on the lunar surface gets pummeled by meteorites and broken into granular material to 10s of meters depth. /1

https://twitter.com/lucassa54749430/status/1867939868216786960

2/ We saw evidence of this at the NASA LCROSS mission’s impact into Cabeus crater in 2009. The target soil was so soft that the spacecraft apparently buried into the soil 2-3 meters deep before meeting much resistance. This caused three observable:

A little background. The earlier version of this mission was the Resource Prospector Mission. When Jim Bridenstine was appointed NASA Administrator, NASA cancelled it without his permission just hours before he was sworn in. I can’t confirm this, but rumors say he was livid! /1

https://twitter.com/drphiltill/status/1813678866709528855

2/ Mr. Bridenstine was appointed by Pres. Trump, and the Trump Transition Team had people assigned to plan space policy. They were calling people for input. I got one such call and the person told me they not only WEREN’T going to cancel Resource Prospector, but instead…

Ok, here’s a little thread of some of the recent, awesome fluid dynamics content on here.

1. Checkout the computer modeling of airflow over an aircraft!

1/N

https://twitter.com/nasaaero/status/1804514797934764109

2. Vortices made visible by water vapor

/2

https://twitter.com/gunsnrosesgirl3/status/1804059338555724218

Four other problems with landing on a flat pad, even if it is a steel with water deluge.

(I’m assuming the larger size of the Super Heavy booster is why they can’t use flat concrete like ordinary booster landings.)

The four problems: … /1

https://twitter.com/drphiltill/status/1800896804336304517

1/ You need enough surface area around the base of the rocket for the gas to flow out, or the engines will choke. Imagine a cylinder extended below the rocket to the ground. The exterior of that cylinder must exceed the exit area of all the rocket nozzles that are firing.

If I had to guess it would be this: same exact material as the existing tiles but just a wee bit thicker. Here is why…

1/N

https://twitter.com/drchriscombs/status/1799980748772094221

2/ Here is what they look like on the inside. They are something like 98% empty space, and the rest is a glass fiber. The fibers touch each other along small contacts, so thermal conductivity is very low. (The scale bar is 100 microns, or 0.1 millimeter.)

This was the same reaction the science team had during the Apollo program — surprise that bone-dry soil could have so much cohesion! See the clods in the footpad image, especially. Short 🧵 1/N

https://twitter.com/usscaliber/status/1798045458323087636

2/ Closeup image of the clods. These are likely very porous, low density clods — very fluffy material — that will easily fall apart between your fingers. Yet they are in blocky shapes somehow held together as the footpad impacted and disrupted the ground.

Untrue. This does touch on something related that actually happened, which people have apparently distorted and used to prop up the dumb conspiracy theory. I will explain… 1/N

https://twitter.com/mikexgorman/status/1783932452945162277

2/ First I’ll tell you what I know about the videos, then the telemetry.

When I analyzed the plume effects of the lunar landings, starting in the late 1990s and early 2000s, I tracked down the original data. One of the guys on my team worked with Houston to get the videos.

NASA now building a flight-ready lunar excavator for a resource utilization pilot plant (not a demonstration — the actual pilot plant) on the Moon. Discussing the challenges of reoeatably setting up the correct lunar soil conditions (compaction, rocks) for testing the lunar excavator on Earth.

I'm tired of reading in the news people proclaim that starting a city on another planet is economically ridiculous when clearly they are just guessing. So I'm finally starting to write a paper on the analysis I did a few years ago that found (to my surprise) it is quite feasible. The main thing ppl don't seem to grasp is that the cost of the extra stuff for Mars, like building a dome, recycling air, using mass for radiation shielding, washing perchlorates from dirt, etc., are utterly trivial compared to the cost of frivolous things we do in our economy.

Part 2. Another thing I think is cool in the papers I linked a few days ago. The quoted thread was about the granular physics of gas digging craters in small experiments, which I thought was cool. This new thread is about lunar geology. 🧵 1/N

https://twitter.com/drphiltill/status/1773551165726159203

2/ The papers described how those small experiments give physics insight that leads to a new equation predicting erosion rate when there is no saltation. I took that new equation and applied it to the Apollo Lunar Modules to predict how much soil was blowing.

Here’s something I think is cool in the new papers that I linked yesterday.

My research group over the years has run many, many small scale experiments where a jet digs a crater against a window so we can see into it. 2/ Something weird we see in these experiments is that the depth of the crater is perfectly described by the logarithm function. Like I mean, perfectly. There are two parameters: a and b, the length scale and (inverse) time scale.

I’m not so sure. The link to the prior estimate is a paper that measures the “blast zone”, which is the region around a lander where the reflectivity of the surface has changed. We have never known exactly what causes this change. Is it from gas blowing the dust texture flat? /1

https://twitter.com/spacedotcom/status/1769695851297788280

2/ Or is it from blowing dust plowing across the surface? Or from engine shutoff when the last sputter of the engine cause a low velocity blanket of dust to fly out to a much smaller distance than normal? The problem has always been that this blast zone is *too small* to be…