In Crusader Kings 3, players can play as the Pope by starting a game as the ruler of the Papal States. This can be achieved by selecting the "Iron Century" start date in 936 AD, which is when the Papal States are an independent realm. Alternatively, players can also start as a ruler in the region and work towards vassalizing the Pope, eventually becoming the Pope themselves. Once in control of the Papal States, players can then take on the role of the Pope, making decisions on matters of faith, diplomacy, and politics within the Catholic Church. **

In Crusader Kings 3, a war of submission requires the target to be a neighboring ruler and have a lower rank than the attacker. The attacker must also have a valid casus belli, such as a claim on the target's title or a de jure claim. Additionally, the attacker must have a valid reason to declare war, such as a vassal refusing to accept their liege's demands. Finally, the attacker must have enough prestige and piety to declare the war, as well as enough troops and resources to potentially win the conflict. **

Self-luminous bodies are objects that emit their own light, as opposed to reflecting light from another source. Examples of self-luminous bodies include stars, the sun, and certain types of light bulbs. These objects generate their own energy through processes like nuclear fusion or electrical current, which produces light as a byproduct. **

No, the luminous clock is not radioactive. The luminescence in the clock is typically achieved using a phosphorescent material that absorbs light and then slowly releases it over time. This process does not involve any radioactive materials. The glow from the clock is simply a result of this light-absorption and emission process. **

A luminous point is a theoretical concept used in physics and optics to represent a source of light that emits light in all directions. It is often used as a simplification in the study of light and its behavior, allowing for easier calculations and analysis. In reality, a luminous point does not exist as a physical object, but it is a useful tool for understanding the behavior of light in various systems. **

Radiant energy is a type of energy that travels through space in the form of electromagnetic waves. It includes visible light, radio waves, microwaves, and other forms of electromagnetic radiation. Radiant energy is produced by the movement of charged particles and is essential for many natural processes, such as photosynthesis in plants and the warmth we feel from the sun. It is also used in various technologies, such as solar panels and communication devices. **

The luminous intensity is specified for reflector lamps because it measures the amount of light emitted in a specific direction, which is important for directional lighting applications such as spotlights and floodlights. Reflectors are designed to control and direct light in a specific direction, so specifying luminous intensity helps to ensure that the lamp is suitable for its intended purpose. Luminous flux, on the other hand, measures the total amount of visible light emitted by a source in all directions, which may not be as relevant for reflector lamps where the focus is on directing light in a specific direction. **

In physics, a self-luminous object is one that produces its own light, such as the sun or a light bulb. These objects emit light due to internal processes, such as nuclear fusion or electrical excitation. On the other hand, an externally luminous object is one that reflects light from another source, such as the moon or a mirror. These objects do not produce their own light but appear illuminated due to the light they reflect from another source. **