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This topic is offered for any NewMars members who might wish to drop off discussion of terminology to be used in a physics context.
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Post #3: tahanson43206 - Conversation with Gemini about "launch point" for objects released from rotating objects in space.
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This post contains a transcript of a conversation with Gemini.Google.com regarding "launch point" for objects to be released from a rotating object in space.
Conversation with Gemini
Hi Gemini! Thank you for all the assistance you've provided with multiple requests. This should be an easy one! I'm looking for the generally accepted term for a point along a line from the center of an object rotating in space where the pull of gravity matches the pull of centripetal force on another object further out on the line from the center of the first object. On Earth, the term used for this location is geostationary orbit or perhaps geosynchronous orbit. I'm wondering if there is another term used for moons or asteroids?
You're touching on a very interesting point of orbital mechanics! While "geostationary" and "geosynchronous" are specific to Earth, the underlying principles apply universally. Here's a breakdown:
Centripetal Force vs. Gravity:
You're correct that the balance between the inward pull of gravity and the outward "pull" of centripetal force (which is really inertia resisting a change in direction) is what keeps objects in orbit.
This balance is fundamental to all orbital mechanics, whether it's Earth, a moon, or an asteroid.General Concepts:
Instead of a single, universally accepted term for that specific point in all cases, the concepts are generally described using:
Orbital mechanics: This broad field covers the physics of orbits, including the interplay of gravity and centripetal force.
Lagrange points: These are specific points in space where the gravitational forces of two large bodies balance each other. While not exactly what you asked, they are areas where the forces balance. These are often used when discussing orbital mechanics of multiple bodies.
Synchronous orbit: while geosynchronous is specific to earth, synchronous orbit can be used for other planetary bodies. This means that the orbital period of the orbiting object matches the rotational period of the body it is orbiting.Key Considerations:
The specific distance where this balance occurs depends on the mass and rotational speed of the central object.
Therefore, each moon or asteroid will have its own unique "synchronous orbit" altitude.In essence, while "geostationary" is Earth-specific, the principles of orbital mechanics and the concept of synchronous orbits apply to all celestial bodies.
Thank you for a helpful first look at this question. I am writing for an audience that includes very knowledgeable people and some less so. I am worried that using the Earth terms when working with an asteroid may be confusing. Please look a bit further, to see if an alternative term shows up in the data you have available.
You're right to be concerned about potential confusion when applying Earth-specific terms to other celestial bodies. It's important to be precise, especially for a knowledgeable audience. Here's a refined look at the terminology:
Key Distinctions:
Geosynchronous vs. Geostationary:
"Geosynchronous" refers to an orbit with a period matching the rotating body's period.
"Geostationary" is a specific type of geosynchronous orbit that is also equatorial and circular, meaning the object appears fixed in the sky.
Therefore, all geostationary orbits are geosynchronous, but not all geosynchronous orbits are geostationary.
Generalizing the Concept:
When dealing with bodies other than Earth, it's best to stick to the more general term:
Synchronous orbit: This accurately describes an orbit where the orbiting object's period matches the rotating body's period. This term is applicable to any celestial body, including asteroids and moons.
To be even more precise, you can state:
"A synchronous orbit around (name of asteroid or moon)"
This removes any ambiguity.
Important considerations for smaller bodies like asteroids.
Many asteroids do not have a perfectly spherical shape, nor do they have even mass distribution. This means that a perfectly stable "synchronous orbit" may be theoretical, and not practical. Instabilities can occur.Why This Matters:
Using "synchronous orbit" avoids the implication of an equatorial, fixed position, which may not be the case for many asteroids or moons.
It emphasizes the core principle: the matching of orbital and rotational periods.Therefore, when writing for your audience, I recommend using "synchronous orbit" as the most accurate and universally applicable term.
Thank you for identifying "synchronous orbit" for the situation we are dealing with here. Please allow me to try to be a bit more specific. There is a proposal on the table to use the rotational energy of an asteroid to deliver mass mined from the asteroid to other locations in the Solar System. The math looks convincing. A large rotating asteroid has kinetic energy that can be measured in very large numbers. The proposition is to (gently) move a payload out, away from the surface of the asteroid while retaining control with a lightweight but strong line. The theory advanced for this scenario is that when the object passes the location where a synchronous orbit might occur, it will begin to experience centripetal force. It is ** this ** force that would permit the payload to be launched onto a trajectory of value. I am hoping you and I might be able to find the correct terminology for this critical point.
You've pinpointed a very specific and fascinating aspect of asteroid manipulation! You're right, the critical point you're describing is where the balance shifts from gravity-dominated to centripetal-force-dominated. Here's a breakdown of how to approach the terminology:
Key Concepts and Challenges:
The Transition Point:
The point you're describing isn't a fixed "orbit" in the traditional sense, but rather a transition zone. It's where the outward fictitious centrifugal force, due to the rotation, becomes greater than the inward gravitational force.
This is not a stable orbital point, but a point of force equilibrium.
Terminology Considerations:
"Escape velocity" is not quite right: While escape velocity is relevant for leaving the asteroid's gravitational influence, it doesn't capture the rotational aspect.
"Synchronous altitude" is close: This refers to the altitude where a synchronous orbit would occur, and it's the closest existing term. However, it's still a bit general.
"Centrifugal dominance point" is descriptive: This phrase accurately conveys the shift in forces.
"Rotational escape point" This phrase also accurately describes the point where the rotational forces will overcome the gravity of the asteroid.Recommendations:
"Synchronous altitude" with clarification:
You can use "synchronous altitude" as a starting point, but always clarify that it represents the altitude where the forces transition from gravity-dominated to centripetal-force-dominated.
Example: "The payload is moved outward to the synchronous altitude, where the rotational force begins to exceed the asteroid's gravity."
"Centrifugal dominance point" or "Rotational escape point"
These phrases are more descriptive.
Example: "Once the payload passes the centrifugal dominance point, the rotational force will launch it onto a desired trajectory."
Define your own term:
Given the specificity of your scenario, you might consider defining a new term for your audience.
Example: "We define the 'rotational launch point' as the altitude where the centrifugal force equals the gravitational force."In summary:
"Synchronous altitude" is the closest existing term, but requires clarification.
"Centrifugal dominance point" and "Rotational escape point" are more descriptive.
Defining your own term can provide the most clarity.I hope this helps you communicate your fascinating concept effectively!
Thank you for your thoughtful and helpful analysis and summary. I'm starting to lean toward "Launch Point" as the best phrase for this specific scenario. To my knowledge, this way of positioning an object for space flight has not been seriously studied before. It is possible the concept may have been discussed in science fiction. The opportunity to mine asteroids and dwarf planets is becoming increasingly attractive, as space launch companies develop capability. Before we close, please see if you can find any evidence this idea has been recorded in the literature available to you.
It's true that the concept of using an asteroid's rotational energy for mass delivery is cutting-edge and pushes the boundaries of current space technology. Here's what I found regarding the concept and related ideas:
Key Findings:
Rotational Dynamics of Asteroids:
There's extensive research on the rotational dynamics of asteroids. Scientists study how asteroids spin, how their rotation rates change due to collisions and the Yarkovsky effect, and the forces that govern their behavior.
This foundational research is crucial for understanding how to manipulate asteroid rotation for practical purposes.
Asteroid Mining and Resource Utilization:
The concept of asteroid mining is gaining traction, with increasing interest in extracting valuable resources from near-Earth asteroids.
Various proposals exist for how to mine asteroids, but the idea of using their rotational energy for mass delivery is relatively novel.
Challenges and Considerations:
Asteroids are often "rubble piles," meaning they're loosely held together. This poses challenges for any manipulation involving rotational forces.
Precise control over the payload and the tether would be essential to ensure accurate trajectory and prevent destabilizing the asteroid.
Related Concepts:
The idea of "space elevators" and "rotating tethers" shares some similarities with the concept you described. These technologies involve using centrifugal force to lift payloads into space.
Research into these technologies could provide valuable insights for developing an asteroid-based launch system.Literature Insights:
Scientific papers focus heavily on the physics of asteroid rotation, the Yarkovsky effect (which alters asteroid spin), and the mechanical properties of asteroids.
While direct, detailed studies of using asteroid rotational energy for mass delivery are less common, the underlying physics is well-established.In Conclusion:
The concept you're describing is at the forefront of space technology, and it's likely that research in this area will increase as asteroid mining becomes more feasible.
"Launch point" is a very good, and easily understood term.
It is very likely that the concept is one that has been discussed in science fiction.I hope this information is helpful.
Thank you! I agree that "launch point" is an expression that should work. While I am away, best wishes for similar success as you assist your many other customers.
You're very welcome! I'm glad we could work through this interesting concept together. Best wishes to you as well!
The warning about not trying this with a rubble pile is worth noting.
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This post is about thermal energy conduction and convection
These terms are of great interest in the Focused Solar Propulsion topic.
I asked Google to see what it could find to clarify the meaning of the terms in the context of thermal energy.
To sum it up, conduction is how energy is transferred, and convection is how matter is moved from one place to another.
Conduction increases thermal energy in matter, while convection moves matter around.
Here is a quote of Google's result:
AI Overview
Learn moreConduction transfers thermal energy through direct contact, adding energy to the object being heated, while convection transfers thermal energy through the movement of fluids, moving the heat around but not necessarily adding more energy.
Here's a more detailed explanation:
Conduction:
Definition: Conduction is the transfer of thermal energy through direct contact between particles of matter.
Mechanism: When warmer particles collide with cooler particles, they transfer some of their kinetic energy (thermal energy) to the cooler particles, causing them to vibrate faster and heat up.
Examples:
Touching a hot stove and getting burned.
A metal spoon heating up when placed in hot water.
Heat traveling through a solid material like a metal rod.Key Point: Conduction primarily occurs in solids, where particles are closely packed and can easily transfer energy through collisions.
Convection:Definition: Convection is the transfer of thermal energy through the movement of fluids (liquids or gases).
Mechanism: Warmer, less dense fluids rise, while cooler, denser fluids sink, creating currents that circulate and transfer thermal energy.
Examples:
Hot air rising from a radiator.
Boiling water, where hot water rises and cold water sinks.
Weather patterns, where warm air masses move and affect temperatures.Key Point: Convection is a bulk movement of fluid, rather than the transfer of energy through collisions at the microscopic level.
In essence, the difference between convection and conduction is that in convection, the matter moves, but in conduction, only the heat does. The ideal gas law provides a good idea of what goes on when one heats something, based on the idea of heat as exciting atoms.
Convection and Conduction | EBSCO Research StartersEBSCO
https://www.ebsco.com › research-starters › science › c...
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