Tidal effects of galaxies orbiting one another with dark energy?

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Suekdccia
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TL;DR Summary
Tidal effects of galaxies orbiting one another in presence of dark energy?
I recently found a question in a physics discussion site [1] about whether there was a "distance" between two galaxies where both the gravitational force and the influence of dark energy would be balanced. The answers and comments seem to indicate that there is indeed such a "radius" around a galaxy.

I was very interested in this, so I contacted the authors of this paper [2] about this phenomenon. I asked them if it could be possible to have a satellite galaxy orbiting a bigger one just in the point where there would be a balance between the gravitational attraction of the bigger galaxy and dark energy, so that the satellite galaxy orbit would not decay (through gravitational waves, tidal forces...) and avoiding its fall eventually towards the bigger galaxy.

They replied that the answer was basically yes, and that they could keep that orbit as long as there was no external perturbation modifying these orbits. But I had one more question about this scenario. My question is:

If that balanced state would be possible, would there still be tidal effects between the two galaxies (So that some of the orbits of planets and stars inside the galaxies could be somewhat modified) but without making the orbits of the galaxies decay over time...?

I mean, imagine a satellite galaxy orbits a bigger galaxy just in the radius distance where the influence of gravity and dark energy are balanced out. Is it physically possible (at least theoretically) that the tidal forces between the galaxies may affect some of the planetary systems' orbits in these galaxies (for example changing the orbits of planets around their stars like for example making them orbit their stars further apart)?

And would these tidal forces disrupt the satellite galaxy from the distance where gravity and dark energy are balanced out? Or without any external perturbation, it should keep orbiting at that distance (even with these tidal forces between the galaxies or the gravitational waves emitted from the orbits around the bigger galaxy)?[1]: https://physics.stackexchange.com/q...ional-source-where-the-influence-of-gravity-a

[2]: https://arxiv.org/abs/1206.1433
 
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Suekdccia said:
TL;DR Summary: Tidal effects of galaxies orbiting one another in presence of dark energy?

I mean, imagine a satellite galaxy orbits a bigger galaxy just in the radius distance where the influence of gravity and dark energy are balanced out. Is it physically possible (at least theoretically) that the tidal forces between the galaxies may affect some of the planetary systems' orbits in these galaxies (for example changing the orbits of planets around their stars like for example making them orbit their stars further apart)?
How much of an effect on the orbits of planets are you expecting at that radial distance?
 
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Suekdccia said:
if it could be possible to have a satellite galaxy orbiting a bigger one just in the point where there would be a balance between the gravitational attraction of the bigger galaxy and dark energy, so that the satellite galaxy orbit would not decay
If there is such a balance, the smaller galaxy won't orbit the larger one. In the Newtonian picture you are using, there has to be an unbalanced inward force on the satellite galaxy for it to orbit the larger galaxy.

The paper you reference recognizes this when it says (p. 2) "The gravitationally bound system can exist only within the sphere of this radius [the radius at which the forces balance]".

Suekdccia said:
If that balanced state would be possible, would there still be tidal effects between the two galaxies
Again using the Newtonian picture, this will obviously be the case in principle since galaxies are extended objects and both the ordinary gravitational force and the dark energy force will vary over the extent of the satellite galaxy. In practice the effects are likely to be quite small (the paper you reference gives formulas you can use to run the numbers if you care to).
 

FAQ: Tidal effects of galaxies orbiting one another with dark energy?

What are tidal effects in the context of galaxies orbiting one another?

Tidal effects refer to the gravitational interactions between galaxies that can lead to distortions in their shapes, the stripping of stars and gas, and the formation of tidal tails and bridges. These effects occur because the gravitational force exerted by one galaxy on another varies with distance, causing differential forces that stretch and compress the galaxies.

How does dark energy influence the tidal interactions between galaxies?

Dark energy, which is thought to drive the accelerated expansion of the universe, can affect the overall dynamics of galaxy interactions by altering the large-scale structure of the universe. However, on the scale of individual galaxy interactions, its influence is relatively minor compared to gravitational forces. Dark energy primarily impacts the rate at which galaxies are moving apart from each other on cosmic scales.

Can tidal interactions between galaxies lead to the formation of new structures?

Yes, tidal interactions can lead to the formation of various structures such as tidal tails, bridges, and rings. These structures are composed of stars and gas that are pulled out from the galaxies due to gravitational forces. Over time, these features can evolve and sometimes trigger new star formation within the tidal debris.

What role do tidal interactions play in galaxy evolution?

Tidal interactions are a significant factor in galaxy evolution. They can lead to the merging of galaxies, the formation of new stars, and the redistribution of gas and stars within and between galaxies. These processes can dramatically change the morphology and star formation rates of the galaxies involved, influencing their long-term evolution.

How do astronomers study tidal effects and dark energy in galaxy interactions?

Astronomers use a combination of observations and simulations to study these phenomena. Observations from telescopes, such as the Hubble Space Telescope, provide detailed images of interacting galaxies and their tidal features. Numerical simulations help scientists understand the underlying physical processes and predict how these interactions will evolve over time. Additionally, the study of dark energy involves large-scale surveys and measurements of the universe's expansion rate.

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