Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos

by Michio Kaku

Remarkable claims require remarkable proof. —Carl Sagan

PARALLEL UNIVERSES, dimensional portals, and higher dimensions, as spectacular as they are, require airtight proof of their existence.

The question is: which came first, the black hole or the galaxy that harbors them?

The second law is the most mysterious and most profound. It states that the total amount of entropy (chaos or disorder) in the universe always increases. In other words, everything must eventually age and run down. The burning of forests, the rusting of machines, the fall of empires, and the aging of the human body all represent the increase of entropy in the universe. It is easy, for example, to burn a piece of paper. This represents a net increase in total chaos. However, it is impossible to reassemble the smoke back into paper. (Entropy can be made to decrease with the addition of mechanical work, as in a refrigerator, but only in a small local neighborhood; the total entropy for the entire system—the refrigerator plus all its surroundings—always increases.)

Scientists believe that an extraterrestrial object, perhaps less than 10 miles across, plowed into the Yucatan Peninsula of Mexico, gouging out a crater 180 miles across and shooting enough debris into the atmosphere to cut off sunlight and darken Earth, causing freezing temperatures that killed off vegetation and the dominant life form on Earth at that time, the dinosaurs.

As the temperature begins to drop throughout the universe, at first creatures may try to lower their body temperature using genetic engineering. This way, they could be much more efficient in using the dwindling energy supply. But eventually, body temperatures will reach the freezing point of water. At this time, intelligent beings may have to abandon their frail bodies of flesh and blood and assume robotic bodies. Mechanical bodies can withstand the cold much better than flesh. But machines also must obey the laws of information theory and thermodynamics, making life extremely difficult, even for robots.

The system must satisfy two conditions: it must remain in equilibrium with its environment, and it must never discard information. But if the universe expands, equilibrium is impossible, because radiation gets diluted and stretched in its wavelength. An accelerating universe changes too rapidly for the system to reach equilibrium. And second, the requirement that it never discard information means that an intelligent being must never forget. Eventually, an intelligent being, unable to discard old memories, might find itself reliving old memories over and over again. “Eternity would be a prison, rather than an endlessly receding horizon of creativity and exploration. It might be nirvana, but would it be living?”

it raises an interesting question that relates to us: could one find haven in a parallel universe if conditions in our own universe became intolerable?

A type I civilization is one that has harnessed planetary forms of energy. Their energy consumption can be precisely measured: by definition, they are able to utilize the entire amount of solar energy striking their planet, or 1016 watts. With this planetary energy, they might control or modify the weather, change the course of hurricanes, or build cities on the ocean. Such civilizations are truly masters of their planet and have created a planetary civilization.

the development of a solar/ion engine may offer a new form of propulsion between the stars. Such slow-moving engines would generate little thrust, but they can maintain that thrust for years at a time. These engines concentrate solar energy from the sun, heat up a gas like cesium, and then hurl the gas out the exhaust, giving a mild thrust that can be maintained almost indefinitely. Vehicles powered by such engines might be ideal for creating an interplanetary “interstate highway system” connecting the planets.

If we pass through a transversable wormhole connecting two time eras, then the buildup of radiation surrounding the wormhole entrance may become infinite, which would be disastrous. (This is because radiation can pass through the wormhole, go back in time, and return after many years to enter the wormhole a second time. This process can be repeated an infinite number of times, leading to an infinite buildup of radiation. This problem can be solved, however, if the many-worlds theory holds, so that the universe splits every time radiation passes through the wormhole, and there is no infinite buildup of radiation. We need a theory of everything to settle this delicate question.)

Wormholes, dimensional gateways, and cosmic strings may exist naturally in outer space. At the instant of the big bang, when there was a huge amount of energy released into the universe, wormholes and cosmic strings may have formed naturally. The inflation of the early universe might then have expanded these wormholes to macroscopic size. In addition, there is the possibility that exotic matter or negative matter exists naturally in outer space. This would help enormously in any effort to leave a dying universe.

Recall that space itself can expand faster than the speed of light (since no net information is being transferred by expanding empty space). Similarly, it may be possible to travel faster than the speed of light by shrinking space faster than the speed of light. In effect, when traveling to a nearby star, we may barely leave Earth at all; we would simply collapse the space in front of us and expand the space behind us. Instead of traveling to Alpha Centauri, the nearest star, we are bringing Alpha Centauri to us.