Mottled

As the pads of a prickly pear cactus (Opuntia engelmannii) die, they often become
mottled in ways that are bound to intrigue a nature photograph—or at least this one.

I made these portraits on September 3rd near the Sierra Nevada entrance to Great Hills Park. The overcast skies preceding rain led me to use flash for a change, and that had the advantage of letting me stop down in all three of these pictures to f/14 for good depth of field and crisp details. In the last picture the drying needles and little fruits had fallen from an Ashe juniper tree (Juniperus ashei).

And here’s a thought for today: You’ve probably heard someone say “You can’t prove a negative.” It depends. Some negatives can be proved. For example, take the question of whether a fraction exists such that when you multiply the fraction by itself the result is exactly 2. An infinite number of fractions exist, so you can’t multiply each and every fraction by itself to find out whether the result is ever 2. Maybe you’ll get close: for instance, 99/70 multiplied by itself gives 9801/4900, which is close to 2, but you can see that the top is just slightly more than twice the bottom. It turns out that no fraction has the property that when you multiply it by itself you get exactly 2. Maybe equally surprising is the fact that smart people were able to prove that negative as long ago as ancient Greece. Hats off to the ancient Greeks.

© 2020 Steven Schwartzman