The counter-rotation is thought to be the result of tidal interactions with another gas rich galaxy some time in the past.
However, a possible exception is when strong tidal interactions with other large masses result in the dispersal of the stars.
The tidal interaction with the secondary component has turned it into a rotating ellipsoidal variable.
Due to their tidal interaction, the Moon recedes from Earth at the rate of approximately 38 mm a year.
In their past, they had fewer tidal interactions or mergers with other galaxies, which could have triggered enhanced star formation.
The two pairs are currently moving farther apart due to tidal interaction, indicating that they were once even more closely associated than today.
This was predicted to be true in cases where tidal interactions with the star are significant.
Synchronous rotation results from so-called tidal interactions between bodies, to be outlined in section 6.1.1.
However, the small value of J 2 indicates that such departures are small, and therefore this tidal interaction will be weak.
Interaction between the two galaxies has just begun, with initial findings of tidal interaction being found in 2012.