Contemplating the Ins and Outs of Reality and Thought

An artist friend gets a huge kick out of people who harbor romantic dreams of traveling to “outer space.” After all, he points out, we already live in outer space. Our little globe floats around in vast blackness, barely making a dent in the fabric of space-time. Space travel is an everyday event. In one year, we’ve gone all the way around the sun; in a few hundred million, we’ll hitch a ride with our solar system around the entire Milky Way.

Scientists and science writers fall into the same fallacy when they speak of entities like “dark-matter” particles as if they only existed “out there,” in “space.”

But as Case Western Reserve University physicist Lawrence Krauss puts it, “These exotic dark-matter particles [are] ‘in here’ as well as ‘out there,’ traversing the Earth, terrestrial laboratories and even ourselves.”

The confusion between inside and outside pervades our thinking about science.

Every quality we ascribe to the things in the outer world originates in the hidden inner world of the atom. Color, flavor, smell, texture, hardness, electrical conductivity--all depend on the invisible architecture of atoms. In this sense, inside is outside.

Making false distinctions between the insides and outsides spreads misleading ideas about science to students as well. I once heard a chemistry teacher tell a group of high school students they wouldn’t like chemistry because it was so “abstract”--so far outside the average teenager’s realm of experience.

On the contrary, chemistry is the force behind just about everything that drives teenagers: love and sex, fear and loathing, pizza and fries, cosmetics and cars. There’s no way to separate the sensations on the outside from the chemistry going on underneath.

In the natural world, inside and outside tend to merge, with no clear wall. The outer membrane of a cell, like the atmosphere of Earth, is permeable. Our skin keeps out wind and rain, but it can’t keep out radiation and subatomic particles. As you read this, signals from radio and television stations are zooming right through your body--along with stray cosmic rays and countless neutrinos.

The ozone layer keeps out most ultraviolet radiation, and the Earth’s magnetic field diverts most of the solar wind toward the poles, but often, some of both seep through. UV rays cause skin cancer, and electrically charged particles blown off the sun disrupt earthly radio transmissions.

Recently, a blast from a “magnetar” halfway across the Milky Way traveled more than 23,000 light-years and rocked Earth’s ionosphere, turning night briefly into day. The fact that it reached out to touch us from so far out in space, one scientist said, reminds us that Earth does not live “in splendid isolation.”

Indeed, one of the great turning points in physics was Isaac Newton’s realization that heaven and earth did not operate on different sets of natural laws. Apples fell because of gravity, but planets were pushed around by angels.

Newton showed that there was no real difference, physically speaking, between the forces that rule the heavens and the Earth. The same gravity that pulled the tower of Pisa askew keeps the moon in its orbit.

Ever since Newton, scientists keep finding more common ground between Earth and outer space. They’ve found volcanoes on Jupiter’s fiery moon Io, and signs of a vast ocean under the ice on Io’s sister, Europa.

Pathfinder’s sojourn on Mars showed that floods and sandstorms and dust devils are as common there as on Earth. Perhaps, even, similar life forms existed in wetter, warmer days of the Red Planet’s evolution.

In the end, nothing turns logic inside out so much as contemplating the shape of the universe itself. Is it infinite, or does it end? And if we do live in a cosmos with an edge, what’s on the outside? Is it different from what is “inside”?

As it turns out, the universe can be finite, yet endless. Think of the surface of Earth, which has a definite surface area, but no “edge.” You can start walking north, and continue round the globe until you wind up where you started. If the universe has a similar shape, you could shoot a rocket into outer space and it would eventually come back and hit you in the head. What begins as inside emerges from outside. And vice versa.