Deorbiting: Possibility and Explanation

  • Context: Undergrad 
  • Thread starter Thread starter deliveryman
  • Start date Start date
Click For Summary

Discussion Overview

The discussion centers around the possibility of an object deorbiting another object it revolves around, exploring various mechanisms and conditions under which this might occur. Participants examine theoretical and practical implications, including atmospheric effects, gravitational interactions, and energy transfer processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that if an object has an atmosphere, it can lead to the eventual deorbiting of another object, similar to the behavior of low-orbit satellites.
  • Others argue that interactions with third objects can disrupt orbits, potentially resulting in deorbiting, as seen in binary stars within globular clusters.
  • A participant mentions that gravitational radiation can cause energy loss in systems, leading to deorbiting over time, citing neutron stars as an example.
  • There is a suggestion that angular momentum exchange due to tidal forces could also contribute to deorbiting, with the Moon's eventual deorbiting around Earth as a potential outcome.
  • Some participants introduce the Poynting-Robertson Effect and the Yarkovsky Effect, noting that these phenomena could influence deorbiting depending on various factors like size and density of the objects involved.
  • One participant questions how an atmosphere would cause deorbiting, leading to an explanation that atmospheric drag slows down satellites, eventually preventing them from maintaining orbit.
  • A claim is made that galaxies may experience outward deorbiting due to dark energy.
  • Another participant discusses gravitational radiation's role in energy loss, questioning its implications for objects like the Moon and pulsars.
  • There is a brief mention that deorbiting can occur through changes in mass, velocity, or transfer of orbital energy.

Areas of Agreement / Disagreement

Participants express various viewpoints on the mechanisms of deorbiting, with no consensus reached on the primary causes or conditions under which deorbiting occurs. The discussion remains unresolved with multiple competing theories presented.

Contextual Notes

Some claims depend on specific definitions of deorbiting and the conditions of the systems discussed. The discussion includes assumptions about the nature of interactions and the effects of different forces, which are not fully explored.

deliveryman
Is it possible for an object to deorbit something it's revolving around? Today my Cosmology teacher said that it was possible, and I just want to know how, she didn't give a very good explanation. I always thought because the Conservation of Anguler Momentum it wouldn't be possible. Explaination, anyone?
 
Astronomy news on Phys.org
If the 'something' has an atmosphere, no matter how tenuous, it will result in the other something deorbiting, eventually. Just like low-orbit satellites.

If the two aren't totally isolated, interactions with third objects could disrupt the orbit, and may result in a 'deorbit'. Something like this happens to some binary stars in globular clusters.

Left alone for long enough, the system will lose energy due to gravitational radiation, and de-orbiting will result. This is happening with a well-observed pair of neutron stars.

If each object is rotating and not perfectly rigid, angular momentum will be exchanged (think of the tides), and deorbiting may happen, depending on the relative sizes, masses, etc. One day the Moon will deorbit due to this mechanism.

Then there is the Poynting-Robertson Effect and the Yarkovsky Effect. Depending on what EM radiation the two somethings are bathed in, and the smaller something's size (and density, albedo, etc), their rotation rates, etc, etc, deorbiting is possible.

I'm sure there are more ways still; e.g. what about outgassing, e.g. a comet in orbit around Mercury?
 
Originally posted by deliveryman
Is it possible for an object to deorbit something it's revolving around? Today my Cosmology teacher said that it was possible, and I just want to know how, she didn't give a very good explanation. I always thought because the Conservation of Anguler Momentum it wouldn't be possible. Explaination, anyone?

Not quite clear on the question. Are you talking about a sattelite deorbitting into its host? That seems to be Nereid's take on things. Or are you asking about a sattelite causing its host to deorbit into something, like the Moon causing the Earth to fall into the Sun?
 
Thank's for that reply, though I still have a question

If the 'something' has an atmosphere, no matter how tenuous, it will result in the other something deorbiting, eventually. Just like low-orbit satellites.

How would having an atmosphere cause something to deorbit?
 
Originally posted by deliveryman
How would having an atmosphere cause something to deorbit?

For the same reason your hand flys back when you stick it out of a car window.

For something to remain in orbit, it must be going fast... very fast.
If you have an atmosphere, the satellite gets slowed down by flying through it, even if the atmosphere is very thin. That slowing eventually gets large enough that the sat can't stay in orbit any longer.
 
Galaxies may deorbit in an outward sense due to dark energy.
 
Gravitational Radiation will cause the Earth's Moon for example to slow down eventually to deorbit, because it's converting some of it's orbital kinetic energy into Gravitational Radiation?

Is that the reason why Gravitational Radiation causes a loss in energy with Pulsars and stuff? Please correct me if I'm wrong.
 
Last edited by a moderator:
deorbiting - - basically, the orbiter either crashes into the orbitee or the orbiter finds a new orbitee. The cause? Changes in mass/velocity/transfer of orbital energy.
 

Similar threads

Undergrad What are the possible states of cold iron balls?
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad A busy and interesting night sky in Mackinaw City
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Reference systems and apparent counter-explanations on Twin Paradox
  • · Replies 5 ·
Replies
5
Views
2K
Is It Safe to Inject a COVID Booster Before the Alcohol Prep Pad Dries?
  • · Replies 18 ·
Replies
18
Views
4K
Undergrad Where can I find publicly accessible data from observatories in Europe?
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad I need some support, please, for a gravity assist analysis
  • · Replies 86 ·
3
Replies
86
Views
9K
Graduate Orbits of a photon that can't quite cross the photon sphere of a BH
  • · Replies 1 ·
Replies
1
Views
968
Undergrad Some questions about absorption lines
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Is it possible to apply Gauss' law to a Klein bottle?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Are two-body orbits with a cosmological constant unstable?
  • · Replies 26 ·
Replies
26
Views
3K