The great 19th-century biologist Thomas Huxley once wrote that the ?question of all questions for humanity... is that of the determination of man?s place in Nature and his relation to the Cosmos?. We might soon be able to provide the answer to this huge riddle as a battery of instruments ? including satellites, gravity-wave detectors and laser devices ? not only begins to give us startling insights into our place in the cosmos, but also forces us to confront the birth and final death of the Universe ? and even the possible existence of parallel Universes.

In the next decade, powerful new satellites will find evidence of earth-like twins orbiting other stars.

So far, our instruments are so crude that we can only detect about 130 giant, Jupiter-sized planets, which are probably devoid of life. In 2006, the Kepler satellite will be launched with a mission to analyse 100,000 stars for large planets.

But in 2014, the Terrestrial Planet Finder will begin to hunt for small, earth-like planets in 500 star systems with a telescope designed to screen out the mother stars, whose light otherwise overwhelms the faint radiation from any nearby planets.

If these efforts pay off, people will have an existential shock, knowing that, when gazing at these twins in the night sky, there might be someone looking back. The thought of detecting intelligence in the Universe is exhilarating to most scientists. However, as science fiction writer Arthur C. Clarke once cautioned: “There may be intelligent life in space or not. Either thought is frightening.”

Cosmology, our understanding of the Universe, might be revolutionised when the Lisa (Laser Interferometry Space Antenna) is launched in 2011. It will orbit the sun at the same distance as the earth, but trailing us by 30 million miles. Consisting of three satellites linked by laser beams, it will form a huge triangle of laser light about three million miles on each side. If a gravity wave from space hits this triangle, it will cause a tiny distortion in the laser beams, which will be detectable by its instruments. (Lisa will detect optical distortions one hundredth the size of an atom.)

Lisa should be able to detect cosmic explosions nine billion light-years from earth, which cut across much of the visible Universe, as well as colliding black holes and even the shock waves emitted a trillionth of a second after the Big Bang, which are still circulating around the Universe. Hence it may be capable of resolving the most perplexing and stubborn question facing cosmology: what happened before the instant of Genesis?

Second universe: Michio Kaku at a bookstore in New York

In the various pre-Big Bang theories that have been proposed, each predicts a different type of shock wave of gravity emitted once the explosion takes place. Lisa, by analysing the precise frequencies and wave-like patterns of the gravity waves emitted at the instant of the Big Bang, should be able to distinguish between them and prove or disprove the theories.

So far, the leading theory is called “inflation” and postulates an unbelievably fast, turbo-charged expansion of the early Universe after the Big Bang of creation. However, if the inflation process happened once, it can happen again. The latest version of this is called “chaotic inflation”, in which Big Bangs can happen randomly. Like soap bubbles that split and sprout other soap bubbles, Universes can bud and create new “baby Universes”. In this picture, Big Bangs are happening all the time, even as you read this article.

But to understand what caused inflation, physicists have to reach for a theory that can incorporate both gravity and all known forms of radiation — the so-called “theory of everything”.

The only candidate for this is called string theory, or M-theory, in which Universes can float in 11-dimensional hyperspace in a “multiverse” of Universes.

Imagine two parallel sheets of paper; ants on one sheet will be invisible to ants on the other, yet they are separated by a few inches. Similarly, if a parallel Universe hovered a millimetre from ours in another dimension, it would be invisible.

As fantastic as these theories are, Lisa may be able to prove or disprove them because each of them leaves behind a different “fingerprint”, or pattern of gravity waves, when the Big Bang occurs.

Ominously, satellites are also giving us a glimpse into the ultimate fate of the Universe. Philosophers have wondered if the Universe will die in fire or ice. The data overwhelmingly favour the Big Freeze rather than a Big Crunch.

The Universe, in fact, is not slowing down, but accelerating, careening out of control in runaway mode. A mysterious form of energy, dubbed “dark energy”, is acting like an anti-gravity force that is pushing the galaxies apart, causing the Universe to accelerate uncontrollably and eventually blowing it apart. In the distant future, billions to trillions of years from now, the stars will exhaust their nuclear fuel, the oceans will freeze, the Universe will turn dark and temperatures will plunge to almost zero. It appears inevitable that all intelligent life will perish when the Universe itself freezes over.

This possibility of “unyielding despair” was explored by the mathematician Bertrand Russell, who wrote, in one of the most depressing passages in the English language, that “no fire, no heroism, no intensity of thought or feeling, can preserve a life beyond the grave... all the labours of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to extinction in the vast death of the solar system; and the whole temple of Man’s achievement must inevitably be buried beneath the debris of a Universe in ruins...”

Today, we believe that space arks may one day preserve life after the death of the sun in five billion years. But can you build a space ark to escape the death of the Universe itself?

The only possible way to avoid the death of the Universe is to leave. Perhaps civilisations billions of years ahead of ours will harness enough energy to punch a hole in space and escape, in a hyper-dimensional space ark, to a new Universe.

Although it seems far-fetched, even preposterous, physicists have seriously considered this possibility using the known laws of physics. Einstein’s equations, for example, allow for the possibility of “Einstein-Rosen bridges” connecting two parallel Universes. (Imagine two horizontal parallel sheets of paper connected by a thin vertical tube.) The energy necessary to create such a “wormhole” connecting two Universes is truly immense — the Planck energy, or 1019 billion electron volts (a quadrillion times the energy of our largest atom smasher).

In desperation, an advanced civilisation may create huge banks of laser beams and atom smashers to create the unbelievably intense temperatures, energy and densities necessary to open up holes in space and leave the Universe.

Calculations show that these gigantic machines must be the size of star systems, but this may be possible for civilisations billions of years ahead of ours. Unfortunately, some preliminary calculations show that the wormhole may only be microscopic in size. If so, an advanced civilisation may resort to shooting molecular-sized robots, called “nanobots”, through the wormhole. Once on the other side, these nanobots will then create huge DNA factories to grow clones and replicas of their creators. Since they will contain the entire database of their civilisation, they will use this to resurrect it in another Universe.

Although the physical bodies of these individuals will die when the Universe freezes over, their genetic twins will live on, so that their civilisation, like a Phoenix, may flourish again. As incredible as these scenarios are, they are consistent with the known laws of physics and biology.

So, when contemplating the question raised by Huxley in 1863, our true role in the Universe may be to spread the precious germ of intelligent life throughout it and, one day, to spread the seed of life by leaving a dying Universe for a warmer one.

(The author is a professor of theoretical physics at the City University of New York)
The Daily Telegraph