Pink Noise - Leonid Korogodski [49]
Via the action–feedback–action loop, the universals of the world are embedded, in the course of evolution, in the very structure of the brain. In [19], Llinás offers the metaphor of a gelatinous cube of electrically conductive material with electric contacts on its surface. The gelatin condenses into filaments if current passes often between the contacts but relaxes back to the amorphous state if no current flows for a while.
In this, you may already recognize the brain plasticity at work.
If the current is based on the sensory input from, for example, playing soccer, then eventually our cube of gelatin would develop a structure that, in a certain sense, encodes the rules of playing soccer, though it would be very different from the familiar game, with a ball, a team of players, and a referee.
Likewise, the brain encodes our experiences in a different format. It is meaningless to ask where exactly in the brain the images we see or our thoughts are to be found, for they are products of the entire process, encoded in our brain through interaction with the world—the action–feedback–action loop.
Though many degrees removed, our thinking is ultimately an internalization of our movement.
GALAXIES IN PLASMA LAB
ONCE UPON A TIME, ASTRONOMERS THOUGHT THAT THE planets, the Sun, and the Moon all moved around the Earth in uniform circular motion. The heavens must be perfect, right? And what could be more perfect than a circle!
One problem: every now and then, planets reverse the direction of their visible motion across the sky, which would be impossible if they turned around the Earth on circular orbits. This so-called retrograde motion of planets forced the introduction of epicycles. An epicycle was a smaller circle on which a planet would turn around a certain point, which itself would turn on a circular orbit (a deferent) around the Earth.
If this sounds complex, you have seen nothing yet. Although retrograde motion now became possible, the calculations still didn’t quite match the observations. Soon, epicycles on epicycles were invented, yet smaller circles on which the planets would turn around a certain point that would move along an epicycle that would move along a deferent around the Earth.
Where did all the original perfect simplicity go?
Unwilling to reconsider the basic assumption that the Earth was at the center, medieval astronomers kept shoring up the ailing geocentric system with ad hoc solutions.
This is a classic example of how science must not be done.
SOME TIME IN THE 1930S, ASTRONOMERS LEARNED HOW TO measure the velocities at which stars rotate around the centers of their galaxies, also known in the specialized scientific lingo as rotation curves. The results surprised them.
By the law of gravity, the stars closest to the center should rotate faster than those found farther away. This is how planets in the solar system rotate around the Sun. But the so-called rotation curves of galaxies were flat almost everywhere, meaning that the rotational velocities of stars around the center of the galaxy were just about equal, no matter what the distance from the center. The stars on the periphery were rotating way too fast. If the galaxy were held together only by the force of gravity, it should have long since fallen apart, ejecting the fast-rotating stars into the intergalactic space, like slingshots.
But this was the time when gravity was held in high esteem. For centuries since Newton, astronomy achieved many important results relying entirely on the law of gravity. And the General Relativity theory by Albert Einstein (1879–1955), only recently proposed and accepted, tickled scientists’ minds and popular imagination. No one was about to suggest that anything but gravity ruled the universe at the galactic scale. Besides, there was no real alternative yet at that point in time.
Thus, dark matter was invented to shore up the gap discovered between theory and observation. No one was willing to suggest a new, unknown—or even an already known!—force other than gravity. But a new, unknown kind of matter