Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] golden ratio in astronomy

On 01/14/2013 03:25 PM, Larry Smith wrote:
I asked my students where we see the golden ratio and one of them
suggested astronomy. This was news to me so I assigned her to
research it and bring it back to class. Most of the URLs she came up
with were wacko stuff and numerology, but one web site looked a
little more interesting. Mario Livio has more credibility than the
other sites, but I'd still thought I'd ask this list about \phi
showing up in equations for Kerr black holes.

The golden ratio has been a magnet for mystics, cranks, and pseudo-scientific
numerologists for a long time. A useful fact-based overview can be found

As for Kerr black holes in particular: A stopped clock is right twice
a day. There are lots of physics formulas involving square roots, and
if you rummage around long enough you will find some that involve the
square root of 5. Note that the result is sensitive to the units used
to measure G and measure spin. If we measured the gravitational coupling
the same way we measured the electromagnetic coupling, the definition
of G would pick up a factor of 4π, and the alleged golden-ratio result
would disappear.

Similarly, the optimal height for the cushion on a billiard table is
proportional to the diameter of the ball. The constant of proportionality
comes out to a magical ratio, namely 7/10. It could have been 1/Φ i.e.
0.61803398875 but actually it is 0.7.