Tidal Forces at Work Between Large & Small Magellanic Clouds?

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Discussion Overview

The discussion revolves around the tidal forces at work between the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC), and the Milky Way galaxy. Participants explore the implications of these forces in the context of galaxy interactions, drawing analogies to tidal effects experienced on Earth.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the LMC and SMC may exert tidal forces on the Milky Way, similar to how the Moon affects Earth's tides.
  • Others argue that the Milky Way likely exerts tidal forces on the Magellanic Clouds, suggesting that the interaction could lead to material being stripped from these smaller galaxies.
  • One participant references historical models by the Toomre brothers, which illustrated how tidal forces can create long tails and streamers of stars and gas in interacting galaxies.
  • Another participant mentions recent observations of the Sagittarius Dwarf galaxy being torn apart by the Milky Way's tidal interactions, indicating that such effects are observable in current astrophysical studies.
  • Concerns are raised about the slow rotational dynamics of the Milky Way, which may make tidal effects less noticeable compared to the rapid rotation of Earth.

Areas of Agreement / Disagreement

Participants express differing views on whether the tidal forces are primarily exerted by the Magellanic Clouds on the Milky Way or vice versa. The discussion remains unresolved, with multiple competing perspectives presented.

Contextual Notes

Participants acknowledge uncertainties regarding the mass ratios and distances involved in the interactions, with some figures provided but not confirmed. The discussion also highlights the complexity of galaxy dynamics and the observational challenges in studying these phenomena.

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I was just wondering about something, and maybe someone can clue me in. I was thinking about how the Large Magellanic Cloud and Small Magellanic Cloud orbit our own galaxy. And I was thinking... I wonder if there are tidal forces at work? I mean, the same way that the Moon causes high tides and low tides on the earth. When a small galaxy orbits our own, does it slightly stretch out our galaxy, like a high tide?
 
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Originally posted by Smiley
I was just wondering about something, and maybe someone can clue me in. I was thinking about how the Large Magellanic Cloud and Small Magellanic Cloud orbit our own galaxy. And I was thinking... I wonder if there are tidal forces at work? I mean, the same way that the Moon causes high tides and low tides on the earth. When a small galaxy orbits our own, does it slightly stretch out our galaxy, like a high tide?

it is a reasonable idea and the analogy is on the right scale I think

the moon is 1/80 the mass of the earth
I am not sure exactly what fraction LMC is of MW but I think
it is about 1/100

distance of LMC is about 50 kpc
radius of MW is about 15 kpc
please someone correct these figures if they are way off
I am only sketching a rough idea

I am thinking that the analogy is very good in that the LMC deforms the gravitational field quite a bit
only it is not noticeable because in MW things revolve so slowly,
sun takes over 200 million years to go around
compared to our lifespan things are just standing still

where by contrast
the Earth rotates fast enough for us to see the tidal effect.
 
Welcome to Physics Forums, Smiley! :smile:
 
Originally posted by Smiley
I was just wondering about something, and maybe someone can clue me in. I was thinking about how the Large Magellanic Cloud and Small Magellanic Cloud orbit our own galaxy. And I was thinking... I wonder if there are tidal forces at work? I mean, the same way that the Moon causes high tides and low tides on the earth. When a small galaxy orbits our own, does it slightly stretch out our galaxy, like a high tide?

More likely our Galaxy exerts tidal forces on the Magellanic Clouds. Also, I seem to remember they found another satellite galaxy on the opposite side of the galactic plane to us. It was found as it has material streaming into the MW. We are canabilising the satellite through tidal forces.
 
Tidal forces? You bet!

The Toomre brothers did some of the first modelling of galaxy interactions, several decades ago now. They showed that tidal forces pulled long tails and streamers of stars and gas out of galaxies which pass near one another. At that time the most spectacular pair had the name The Antennae; the Toomre's model reproduced the wonderful streamers very well.

More recently, the newly installed ACS instrument in the Hubble Space Telescope took a wonderful picture of another tidal tail from an interacting galaxy pair. The HST collection also has a close-up of Stephan's Quintet.

The Saggitarius Dwarf, which thed refers to, has just been in the news. Observations have shown that it is truly being torn to pieces by the Milky Way, through tidal interaction.

Lastly, but not so widely reported, is a study showing a globular cluster being shredded by close encounters of the Milky Way kind. See this link:
http://spaceflightnow.com/news/n0206/08survey/
 

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