I just read that Dr. Kasevich and crew at Stanford, are designing an experiment to test the theory that objects fall at rates independent of their mass, to a precision of 20 decimal places.
Now, Galileo already did this atop the Leaning Tower, but these Stanford guys are serious. Serious to 1 part in 100,000,000,000,000,000,000. No kidding. So, if it's successful, they can proclaim, "Galileo was right!"
As a gedenken experiment,
Define m1= mass of Stan Laurel
Define m2= mass of Oliver Hardy
Assume that m2/m1=2
Assume Laurel is spherical and Ollie is cylindrical and that m2/m1=2
Assume that the acceleration differs between Stan and Ollie by 1 part in 10^20, the precision of the present experement.
Assume also that the acceleration is constant, for both.
Then, in order that Ollie hit first by one diameter (assuming a spherical Hardy, as aforeto mentioned, R(Ollie)=2 Meters, the distance they must fall is 21 light years.
A light year, if you're still awake, is 5,878,499,810,000 miles or 5.8 TRILLION miles. Heck, that's not even 1 National Debt Ceiling.
Sometimes it is helpful to explain the sophistication of these experiments with examples everyone can relate to.