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Monday, May 17, 2010

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


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


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


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

which is equivalent to

E = 2×1040 Tons of TNT

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( 32M - 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!

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