Understanding the (restricted) three body problem

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In summary, the problem has 9 degrees of freedom and requires n independent first integrals to be solved using quadrature. However, the independent first integrals present (center of mass, total momentum, total angular momentum, and total energy) are not enough to qualify as integrable. In the inertial frame, both the Lagrangian and Hamiltonian are not conserved due to explicit time dependence. However, transforming to the synodic frame removes the time dependence and conserves these quantities, although the Hamiltonian is not the total mechanical energy due to the presence of centrifugal and Coriolis forces. The total energy is not conserved in the synodic frame due to inertial forces, but it is conserved in the inert
  • #1
throneoo
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Hello. Recently I've been trying to understand this problem but I'm not sure if I'm doing it correctly. So I'd like to show you some statements formed from my understanding on the subject and you guys could correct me if I'm wrong.

General:
1)The problem has 3*3=9 degrees of freedom and n independent first integrals is needed to solve it using quadrature (Integrable).

2)The independent first integrals here is the center of mass/ total momentum/ total angular momentum (3) and total energy (1) =4 which is not enough to be qualified as integrable.

Circularly restricted (3D)
3) In the inertial frame, the lagrangian is explicitly time dependent as the distances from the two massive bodies depend explicitly on time (constant rotation), hence both the lagrangian and hamiltonian are not conserved.

4)Transforming to the synodic (rotating) frame removes the explicit time dependence so those quantities are conserved, but the hamiltonian is not the total mechanical energy (due to the centrifugal and coriolis force)

5)Total energy is not conserved in the synodic frame due to the inertial forces. Presumably it is conserved in the inertial frame despite the fact that the gravitational influence from the smallest body is neglected.

6) The Lagrangian points are the only equilibrium points in the synodic frame.

Thanks for your help! I might add more to the thread.
 
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  • #2
This is an interesting problem for me, too. What books are you using?
 
  • #3
dextercioby said:
This is an interesting problem for me, too. What books are you using?
Celestial Dynamics by Dvorak and Lhotka is the main text. I also read a lot of articles on this subject
 

1. What is the three body problem?

The three body problem is a mathematical and physical problem that involves predicting the motion of three objects interacting with each other through gravitational forces. It is considered one of the most challenging problems in classical mechanics.

2. Why is the three body problem difficult to solve?

The three body problem is difficult to solve because it does not have an exact analytical solution. The motion of three bodies is highly chaotic and unpredictable, making it challenging to accurately predict their movements over time.

3. What is the restricted three body problem?

The restricted three body problem is a simplified version of the three body problem in which one of the bodies is significantly smaller than the other two. This means that the smaller body's gravitational influence on the other two bodies can be neglected, making the problem slightly easier to solve.

4. How is the restricted three body problem relevant in astronomy?

The restricted three body problem is relevant in astronomy because it helps us understand the motion of celestial bodies, such as planets and moons, that are influenced by multiple gravitational forces. It is also used to study the dynamics of binary star systems and the motion of spacecraft in the solar system.

5. What are some applications of the study of the restricted three body problem?

The study of the restricted three body problem has various applications in fields such as space travel, satellite orbits, and astrophysics. It also has practical applications in designing spacecraft trajectories and predicting the motion of objects in our solar system.

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