Quote:
Originally Posted by xelasnave
If black holes exist they have little influence on their galaxies (if they are there) .. whereas we are presented with the notion that they are absolutely central and controlling upon galactic evolvement..how could this be so if their influence is so minimal when it reaches us let alone the outter regions of our galaxy....consider what influence does sag A have upon our region of space...zip thats what  ..how much mass do you need in a black hole given the inverse square rule to "balance" or influence the gallaxy..well it seems we need much bigger than sag A  ....so I dont see their value on "control" of the galaxy...anyways thats my effort to spark some thinking on these matters rather than settling for a simple acceptance of what we are fed.... 
alex  |
Alex,
I think the evidence for the supermassive black hole in Sgr A is proving to be fairly strong. However I agree with you on the point you made above.
Out of curiosity, I did some rough calculations on the Sgr A* supermassive black hole of 4 million solar masses, distance 26000 light years. You would need roughly 37000 such black holes at the centre of the Galaxy to produce the same gravitational force on our Sun as the Sun would have on the planet Neptune. I would have to say that its gravitational effect is fairly insignificant at 26000 light years.
Anyone with some maths knowledge can check these calculations ...
Mass of the Sun is 2x10^30 kg, mass of Neptune is 10^26 kg.
4 million solar masses is 8x10^36 kg.
One light year is 9.46x10^12 km.
26000 light years is 2.46x10^17 km.
Distance of Neptune from the Sun is 4.5x10^9 km.
Using the formula F/G=Mm/r^2 gives a result for
Sgr A* & Sun of F/G=(8x10^36)x(2x10^30)/(2.46x10^17)^2=2.7x10^32
Sun & Neptune of F/G=(2x10^30)x(10^26)/(4.5x10^9)^2=10^37
10^37/(2.7x10^32)=37000
Regards, Rob