Wednesday, June 24, 2009

Ranking the most powerful forces in the Universe

There are a large number of forces at work in the Universe, some more powerful than others -- and I'm not talking about the four fundamental forces of nature. A force in the context I'm talking about is any phenomenon in Universe that exhibits a powerful effect or influence on its environment. Many of these phenomenon quite obviously depend on the four basic forces to function (gravity, electromagnetism, the weak interaction and the strong interaction), but it's the collective and emergent effects of these fundamental forces that I'm interested in.

And when I say power I don't just mean the capacity to destroy or wreak havoc, though that's an important criteria. A force should also be considered powerful if it can profoundly reorganize or manipulate its environment in a coherent or constructive way.

Albert Einstein once quipped that the most powerful force in the Universe was compound interest. While he does have a point, and with all due respect to the Master, I present to you my list of the four most powerful phenomenon currently making an impact in the Universe:

4. Supermassive Black Holes

There's no question that black holes are scary; it's the only part of the Universe that can truly destroy itself.

Indeed, Einstein himself, whose Theory of Relativity opened the door to the modern study of black holes, noted that "they are where God has divided by zero." And it's been said that the gravitational singularity, where the laws of physics collapse, is the most complex mystery of science that still defies human knowledge.

Somewhat counterintuitively, black holes take the weakest of the four basic forces, gravity, to create a region of space with a gravitational field so powerful that nothing, not even light, can escape its pull. They're called "black" because they absorb all the light that hits them and reflect nothing. They have a one-way surface, the event horizon, into which objects can fall, but out of which nothing (save for Hawking Radiation) can escape.

Black holes can also vary in size and gravitational intensity. Supermassive black holes are a million to a billion times the mass of a typical black hole. Most galaxies, if not all, are believed to contain supermassive black holes at their centers (including the Milky Way).

And recent studies are now suggesting that they are much larger than previously thought. Computer models reveal that the supermassive black hole at the heart of the giant galaxy M87 weighs the same as 6.4 billion suns—two to three times heavier than previous estimates.

That's a lot of pull.

Indeed, should anything have the misfortune of getting close enough to a supermassive black hole, whether it be gas, stars or entire solar systems, it would be sucked into oblivion. Its gravitational pull would be so overwhelming that it would hurl gas and stars around it at almost the speed of light; the violent clashing would heat the gas up to over a million degrees.

Some have suggested that the supermassive black hole is the most powerful force in the Universe. While its ability to destroy the very fabric of space and time itself is undeniably impressive (to say the least), its localized and limited nature prevent it from being ranked any higher than fourth on my list. A black hole would never subsume an entire Galaxy, for example, at least not within cosmologically long time frames.

3. Gamma-Ray Bursts

The power of gamma-ray bursts (GRB) defies human comprehension.

Imagine a hypergiant star at the end of its life, a massive object that's 150 times larger than our own. Extremely high levels of gamma radiation from its core is causing its energy to transform to matter. The resultant drop in energy causes the star to collapse. This results in a dramatic increase in the thermonuclear reactions that was burning within it. All this added energy overpowers the gravitational attraction and it explodes in a fury of energy -- the hypergiant has gone hypernova.

This is not the stuff of fiction or theory -- explosions like this have been observed. Hypernovas of this size can instantly expel about 10X46 joules. This is more energy than our sun produces over a period of 10 billion years. 10 billion years! In one cataclysmic explosion!

Hypernovas can wreak tremendous havoc in its local area, effectively sterilizing the region. These explosions produce highly collimated beams of hard gamma-rays that extend outward from the exploding star. Any unfortunate life-bearing planet that should come into contact with those beams would suffer a mass extinction (if not total extinction depending on its proximity to the supernova). Gamma-rays would eat up the ozone layer and indirectly cause the onset of an ice age due to the prevalence of NO2 molecules.

Supernovas can shoot out directed beams of gamma-rays to a distance of 100 light years, while hypernovas disburse gamma ray bursts as far as 500 to 1,000 light years away.

We are currently able to detect an average of about one gamma-ray burst per day. Because gamma-ray bursts are visible to distances encompassing most of the observable Universe -- a volume encompassing many billions of galaxies -- this suggests that gamma-ray bursts are exceedingly rare events per galaxy. Determining an exact rate is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for hypernova-type events) is about one burst every 100,000 to 1,000,000 years.

Thankfully, hypergiant Eta Carinae, which is on the verge of going nova, is well over 7,500 light years away from Earth. We'll be safe when it goes off, but you'll be able to read by its light at night-time.

But not so fast -- our safety may not be guaranteed. Some scientists believe that gamma-ray busters may be responsible for sterilizing giagantic swaths of the galaxy -- in some cases as much as a quarter of the galaxy. Such speculation has given rise to the theory that gamma-ray bursters are the reason for the Fermi Paradox; exploding stars are continually stunting the potential for life to advance, making it the 3rd most powerful force in the Universe.

2. Self-Replication

A funny thing started to happen about 8 billion years ago: pieces of the Universe started to make copies of itself. This in turn kindled another phenomena: natural selection.

While this might not seem so impressive or powerful in its own right, it's the complexification and the emergent effects of this process that's interesting; what began as fairly straight forward cellular replication, at least on Earth, eventually progressed into viruses, dinosaurs, and human beings.

Self-replicating RNA/DNA has completely reshaped the planet, its surface and atmosphere molded by the processes of life. And it's a process that has proven to be remarkably resilient. The Earth has been witness to some extremely calamitous events over its history, namely the Big Five Mass Extinctions, but life has picked itself up, dusted off, and started anew.

Now, what makes self-replication all the more powerful is that it is not limited to biological substrate. Computer viruses and memes provide other examples of how self-replication can work. Replicators can also be categorized according to the kind material support they require in order to go about self-assembly. In addition to natural replicators, which have all or most of their design from nonhuman sources (i.e. natural selection), there's also the potential for:
  • Autotrophic replicators: Devices that could reproduce themselves in the wild and mine their own materials. It's thought that non-biological autotrophic replicators could be designed by humans and could easily accept specifications for human products.
  • Self-reproductive systems: Systems that could produce copies of itself from industrial feedstocks such as metal bar and wire.
  • Self-assembling systems: Systems that could assemble copies of themselves from finished and delivered parts. Simple examples of such systems have been demonstrated at the macro scale.
It's conjectured that a particularly potent form of self-replication will eventually come in the form of molecular manufacturing and the introduction of self-replicating nanobots. One version of this vision is connected with the idea of swarms of coordinated nanoscale robots working in tandem.

Microscopic self-replicating nanobots may not sound particularly powerful or scary, but what is scary is the prospect for unchecked exponential growth. A fear exists that nanomechanical robots could self-replicate using naturally occurring materials and consume the entire planet in their hunger for raw materials. Alternately they could simply crowd out natural life, outcompeting it for energy. This is what has been referred to as the grey goo or ecophagy scenario. Some estimates show, for example, that the Earth's atmosphere could be destroyed by such devices in a little under two years.

Self-replication is also powerful in terms of what it could mean for interstellar exploration and colonization. By using exponentially self-replicating Von Neumann probes, for example, the Galaxy could be colonized in as little as one to ten million years.

And of course, if you can build you can destroy; the same technology could be used to sterilize the Galaxy in the same amount of time [for more on this topic read my article, "Seven ways to control the Galaxy with self-replicating probes"].

Consequently, self-replication sits at #2 on my list; its remarkable ability to reshape matter, adapt, grow, consume, build and destroy make it a formidable force to be reckoned with.

1. Intelligence

Without a doubt the most powerful force in the universe is intelligence.

The capacity to collect, share, reorganize and act on information is unlike anything else in this universe. Intelligent beings can build tools, adapt to and radically change their environment, create complex systems and act with reasoned intention. Intelligent beings can plan, solve problems, think abstractly, comprehend ideas, use language and learn.

In addition, intelligence can reflect on itself, predict outcomes and avoid peril; autonomous systems, for the most part, are incapable of such action.

Humanity, a particularly intelligent bunch owing to a few fortuitous evolutionary traits, has -- for better or worse -- become a force of nature on Earth. Our species has reworked the surface of the planet to meet its needs, significantly impacting on virtually every other species (bringing many to extinction) and irrevocably altering the condition of the atmosphere itself. Not content to stay at home, we have even sent our artifacts into space and visited our very own moon.

While some cynics may scoff at so-called human 'intelligence', there's no denying that it has made a significant impact on the biosphere.

Moreover, what we think of as intelligence today may be a far cry from what's possible. The advent of artificial superintelligence is poised to be a game-changer. A superintelligent agent, which may or may not have conscious or subjective experiences, is an intellect that is much smarter than the best human brains in practically every field, including problem solving, brute calculation, scientific creativity, general wisdom and social skills. Such entities may function as super-expert systems that work to execute on any goal it is given so long as it falls within the laws of physics and it has access to the requisite resources.

power. And that's why it's called the Technological Singularity; we have no idea how such an agent will behave once we get past the horizon.

Another more radical possibility (if that's not radical enough) is that the future of the Universe itself will be influenced by intelligent life. The nature of intelligence and its presence in the Universe must always be called into question. There exists only one of two possibilities: intelligence is either 1) cosmological epiphenomenon, or 2) an intrinsic part of the Universe's inner workings. If it's the latter, perhaps we have some work to do in the future to ensure the Universe's survival or to take part in its reproductive strategy.

Theories already exist in regards to stellar engineering -- where a local sun could be tweaked in such a way to extend its lifespan. Future civilizations may eventually figure out how to re-engineer the Universe itself (such as re-working the constants) or create an escape hatch to basement universes. Thinkers who have explored these possibilities include Milan Cirkovic, John Smart, Ray Kurzweil, Alan Guth and James N. Gardner (for example, see Gardner's book Biocosm: The New Scientific Theory of Evolution: Intelligent Life is the Architect of the Universe).

Intelligence as a force may not be particularly impressive today when considered alongside supermassive black holes, gamma-ray bursts and exponential self-replication. But it may be someday. The ability of intelligence to re-engineer its environment and work towards growth, refinement and self-preservation give it the potential to become the most powerful force in the Universe.

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