Evolution’s Gravity: A Paean to Natural Selection


Image: NAUTILUS
Physicists speak of four fundamental forces that govern the interactions among the bits of matter that make up our universe.

By Michael McCullough | NAUTILUS

The strongest of these four forces, aptly known as the Strong Force, is so powerful that it can keep an atom’s positively charged protons from ripping the atom’s nucleus apart as their mutually repellent positive charges push them in opposite directions. The second fundamental force, electromagnetism, is 137 times weaker than the strong force, but its ability to cause bits of matter with opposing electrical charges to attract each other, and to cause bits of matter with like charges to avoid each other, is what gives unique three-dimensional structure to atoms, molecules, and even the proteins that form the building blocks of our body’s cells. At only one-millionth the strength of the strong force, the third fundamental force—the so-called weak force—changes quarks from one bizarre “flavor” to another and gives rise to nuclear fusion reactions.

The weak force deserves a better name: It’s actually the fourth force—gravity—that’s the weakling of the bunch. At only 6/1,000,000,000,000,000,000,000,000,000,000,000,000,000 the strength of the strong force, the influence of gravity on the interactions of protons, quarks, and other subatomic particles amounts to, well, about as close to zero as you can get. When I use the refrigerator magnet that holds up my kid’s school photo to lift the ring of keys on the kitchen table, the magnet easily overcomes the gravitational pull of the entire planet. At Subatomic Beach, gravity is the scrawny guy who’s always getting sand kicked in his face.

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