Stephen Wolfram: One Rule to Ring them All...

Guide:

• 0:00 Intro 
• 1:08 Chapter 1: The limits of theoretical physics 
• 5:50 Chapter 2: A computational understanding of the world 
• 12:03 Rule 30: a simple program that outputs pure randomness 
• 15:48 Evolution and machine learning are the same trick 
• 18:19 What computational irreducibility means for science 
• 25:00 Chapter 3: A new kind of theory of everything 
• 31:36 The ruliad: every possible computation, in one object 
• 35:03 The second law, explained by the limits of our minds 
• 38:38 Why the universe exists isn't the real question — why we do is 
• 42:53 Chapter 4: If the universe is a program, what is the meaning of life? 
• 44:59 Free will as a side effect of computational irreducibility 
• 48:06 AI as a civilization we're learning to coexist with

JAXA on Keeping Up with the Xi's...

from Google AI:

On July 11, 2026, the Japan Aerospace Exploration Agency (JAXA) successfully conducted the first flight and vertical landing test of its RV-X (Reusable Vehicle eXperiment) prototype rocket. The trial took place early in the morning at the Noshiro Rocket Testing Center located in Akita Prefecture, northeastern Japan.

The sub-minute test marks a major breakthrough for Japan as it enters the vertical takeoff and vertical landing (VTVL) arena to drastically cut future space mission costs.

Key Flight Statistics

• Flight Duration: Approximately 40 to 55 seconds.
• Maximum Altitude: Climbed to about 11 meters (36 feet).
• Lateral Movement: Traveled 16 meters (52 feet) horizontally before executing its touchdown.
• Stability: Maintained a perfectly upright position under full autonomous engine control throughout the maneuver.

Vehicle Specifications

• Dimensions: Standing 7.3 meters (23.9 feet) tall with a diameter of 1.8 meters (5.9 feet).
• Propulsion: Powered by a highly durable Liquid Oxygen / Liquid Hydrogen (LOX/LH2) engine that underwent 165 combustion tests prior to the flight.
• Landing Gear: Equipped with four shock-absorbing legs to manage the touchdown impacts.
• Development: Co-developed alongside Mitsubishi Heavy Industries.

Future Roadmap

The data collected during this short-hop flight will be integrated into the design of Callisto, a larger reusable vehicle currently being co-developed by Japan, France, and Germany. JAXA plans to systematically expand flight parameters, targeting altitudes up to 100 meters in subsequent tests. The long-term objective is to introduce a fully operational reusable flagship launch fleet by the 2030s to replace the currently single-use H3 rocket.

Engine Configuration of the RV-X

The RV-X prototype relies on a highly specialized engine configuration designed explicitly for the extreme thermal and mechanical demands of repeated vertical takeoff and landing (VTVL) operations.

• Propellant Combo: Uses Liquid Oxygen (LOX) and Liquid Hydrogen (LH2), mirroring the clean-burning fuel setup of Japan's core flagship rockets.
• Thrust Throttleability: Engineered to dynamically throttle its thrust output, allowing the vehicle to hover precisely and slow down to a gentle halt just meters above the ground.
• Extreme Reusability: Prior to the actual free-flight test, this specific engine architecture underwent 165 rigorous combustion tests to prove it could ignite, burn, and shut down repeatedly without structural degradation.
• Aerodynamic Control: The engine nozzle integrates advanced gimbaling systems to vector thrust dynamically, providing the primary stability control that kept the vehicle upright during its 16-meter horizontal shift.

The CALLISTO Project Parameters

The insights gained from the Noshiro RV-X hops feed directly into CALLISTO (Cooperative Action Leading to Launch System Innovation for Stage Toss-back Operations). This is an international venture between JAXA (Japan), CNES (France), and DLR (Germany).

• The Core Objective: To build, fly, and recover a highly complex, reusable suborbital vehicle to master the flight mechanics, software algorithms, and ground operations required for a commercial-scale reusable first stage.
• Vehicle Scale: Significantly larger and faster than the RV-X, CALLISTO is designed to break the sound barrier, perform complex aerodynamic maneuvers at high altitudes, and return to a designated landing pad.

Division of Labor:

JAXA: Leading the development of the LOX/LH2 propulsion system (scaling up the tech proven by RV-X) and the onboard fuel tanks.

CNES: Designing the ground control center, launch pad infrastructure, and overall system flight safety architectures.

DLR: Responsible for the complex aerodynamic control surfaces (such as the fins used to steer through the atmosphere), the landing gear mechanics, and wind tunnel data analysis.

Operational Goal: The vehicle will execute a sequence of test flights returning to the Guiana Space Centre in Kourou, French Guiana, paving the way for Europe and Japan to field cost-effective, reusable heavy-lift rockets by the 2030s.

Me and My Markov Blanket