Abstract:  This short chapter discusses some aspects of post 
accretion velocity of black holes as they gravitationally 
draw in smaller sized mass elements.



                   Accelerating cue balls?

In chapter 26 of Joseph_Sixpack's intuitive Opus Dopus we 
mindlessly mention that a large black hole accumulates some 
velocity after having gravitationally drawn in and accreted 
other nearby galaxies.  The forward velocity being 
established by the gravitational attraction of the victim 
masses.

Hypothesis:  Well, then we could presume that the forward 
motion of the accreting black hole would in time lead it to 
other galaxies and smaller masses which would, in time keep 
accelerating the accreting mass to ever higher and higher 
velocities.

That would lead to the hypothesis that there could be black 
holes in the universe that are traveling at high speeds 
picking up anything and everything that they came across, 
sort of a giant vacuum cleaner.

Our little galaxy wouldn't even know what hit it if it was 
in the path of one of these speedball black holes.



                     but consider this:

About more than a couple of months later after posting and 
during rereading of chapter 26, the thought dawned on me 
that the forward velocity portion of the velocity generated 
by the pull of gravity from the galaxies being accreted 
would be reduced to near zero by the f=ma of the galaxies 
hitting the accreting black hole.

That is, both attracting and closing velocities generated by 
the pull of gravity from each closing mass would sort of 
divide (cancel) each other out when they bonked into one 
another leaving a net forward velocity of near zero..

oh well...  

There would therefore be no accumulating velocity increases 
by the accreting black hole.

So it appears that the original conceptional hypothesis of 
cruising black holes might be in need of modification.  

So we may not have to worry too much about the accretion 
resulting velocity of black hole night cruisers, as they 
themselves are whacked to stationary status (or at least to 
their original x,y,z velocities) by their gravitational 
accretions.

With one exception:  That is when one black hole uses the 
mass of the other to accelerate out of a near collision 
closing orbit to greater than original velocities.  

Scientists use this sling shot method to get our space probe 
devices to the outer planets i am told.

Anyhow, these moving black holes would eventually slow down 
as they serially bonk into other visible and invisible 
masses and have their forward energy absorbed by other 
masses that happened to be in their path.