Possible criteria or parameters for planetary collision?

In summary, the conversation discusses the potential criteria or parameters that may affect planetary collisions, specifically in regards to the behavior of moons after the collision. It is mentioned that the orbital period of the moons compared to the planet's rotation period and the size of tides on the planet can determine whether the moon will spiral outwards or inwards. The concept of "positive" and "negative" in this context is dependent on arbitrary definitions.
  • #1
Positron137
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Possible "criteria" or parameters for planetary collision?

Suppose a computer model were created to simulate two proto-type planets on a collision course (for example, the Earth-Moon collision in the Hartman theory of the Moon formation). We know that the Moon is spiraling outwards (tidal acceleration). The first question I have, is why do certain moons of planets spiral outwards or inwards (into a main planet)? Second question: is the tendency of these moons to spiral outward or inward dependent on a "criteria: of some sort of the formation of the moon (so if a moon, or moons were created by a proto-planet collision, or by gravitational attraction past the Roche radius)? WOuld there have to be several parameters regarding the collision to determine the behavior of the moon's orbit? And if there are parameters, what would they be? Thanks!
 
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  • #2
I think you are mixing two different things here.

- the collision event and moon formation. That happens in (relatively) short timescales.
- orbital changes long afterwards. The moon spirals out for billions of years now.

The orbital radius of a moon increases if the orbital period is longer than a day of the planet, and if the planet shows significant tides due to this moon.
 
  • #3
Ah ok. I understand. So I guess the proper thing to ask is, after the collision though, what determines whether the moon will tidally accelerate (orbit outward) or decelerate (spiral inward) after billions of years?
 
  • #4
If there are no other objects influencing this:
The periods of one moon orbit compared to the rotation period of the planet determines the sign (neglecting the rotation of the moon here), the size of tides on the planet (and moon) determines the magnitude.
 
  • #5
Ok. What do mean by "sign" exactly?
 
  • #6
Outwards (like our moon: one orbit takes longer than a day) or inwards (like Phobos at Mars).
 
  • #7
Ah ok. So is it "positive" if it orbits outwards, and "negative" if it orbits inwards?
 
  • #8
That depends on your arbitrary definition of "positive" and "negative".
 
  • #9
I see. Alright.
 

1. What factors determine the possibility of a planetary collision?

The possibility of a planetary collision depends on various factors such as the size and mass of the planets involved, their orbital paths, and the gravitational forces between them. Other factors that can influence the likelihood of a collision include the presence of other celestial bodies in the area and the effects of tidal forces.

2. How can scientists predict the likelihood of a planetary collision?

Scientists use mathematical models and simulations to predict the likelihood of a planetary collision. These models take into account the known parameters of the planets and their orbits, as well as any potential gravitational interactions with other objects in the vicinity. Advanced technologies like telescopes and spacecraft also play a crucial role in observing and tracking potential collisions.

3. What are some potential consequences of a planetary collision?

A planetary collision can have significant consequences, depending on the size and speed of the colliding bodies. It can result in the destruction of one or both planets, the formation of a new planet, or the disruption of the orbits of other nearby planets. The impact can also release a large amount of energy, leading to changes in the atmosphere and climate of the affected planets.

4. Are there any criteria for determining the severity of a planetary collision?

While the severity of a planetary collision can vary, there are some criteria that scientists use to determine the potential impact. These include the speed and angle of the collision, the composition and density of the planets, and the presence of any protective factors such as an atmosphere or magnetic field. Additionally, the size and location of the impact can also play a role in the severity of the collision.

5. Can planetary collisions be prevented or mitigated?

The possibility of a planetary collision cannot be completely eliminated, but steps can be taken to mitigate the impact. Scientists and space agencies are actively monitoring potentially hazardous objects and developing technologies to deflect or redirect them away from a collision course. However, the success of these measures depends on early detection and sufficient time to implement them.

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