Holy Cow!

Related Link » Monster black hole ejected from host galaxy
“A super-massive black hole — heavier than one billion suns — appears headed on an exit out of its home galaxy at 670,000 miles-an-hour.”
— By Dan Vergano, USA Today, 05/17/10

Question: What is the kinetic energy with which this monster was ejected?

Answer: The kinetic energy "E", of a mass "m", having a speed "v" is computed as follows:

E = (½)mv²

where

m = mass of a billion suns = 2×10³⁹ kilograms

and

v = 670,000 miles/hour = 299,517 meters/second = 0.1% of lightspeed

yielding

E = (10³⁹ kg)(3×10⁵ m/s)² = 9×10⁴⁹ joules

which is equivalent to

E = 2×10⁴⁰ Tons of TNT

Q.E.D.

Such a monstrous amount of energy, however, corresponds to a seemingly small index of earthquake-magnitude "M", which can be computed as follows (as shown in my post Energy of Earthquake in Logarithmic Nutshell):

E [Tons of TNT] = 2×10⁴⁰ = 10^{( 3⁄₂M - 3)}

Solving for M, we get

M = ²/₃(log(2×10⁴⁰) + 3) = 28.9

The corresponding value of M for the Yucatán Peninsula Impact Event was 11¹/₃ (as I previously computed in my above mentioned post).

Post #1,277 Holy Cow!