Fairly recently my buddy and I got into a discussion regarding the future of computing; specifically, Artificial Intelligence (AI). Having grown up with television shows such as (classic) “Star Trek”, I have been amazed at how reality has actually surpassed our fictional imagination regarding computer capabilities. The cell phones we routinely carry with us today far surpass the computational power of the Space Shuttle. But are we on a pathway to someday creating a real “Lt. Cmdr. Data”? Well…
The silicon micro chip and modern science fiction has suggested, perhaps somewhat mythically, that future AI might manifest itself as some type of Silicon Life Form. Unfortunately, as chemists point out, silicon as a basis for a living organism has some major drawbacks compared to carbon. Though silicon has the ability to bond with other atoms, such molecules are relatively unstable. As a result the largest silicon compound ever observed was limited to only six silicon atoms. Carbon, on the other hand, is able to produce long chains of hundreds of thousands of atoms. Large complex chains of carbon atoms have the ability to form “left-handed” versions, which build amino acids, and proteins, and “right-handed” versions which form sugars. Carbon dioxide is a gas which dissolves easily in water, whereas Silicon dioxide is a solid.
Ok, so perhaps then we could conclude that a silicon life form might exist less as a carbon-based “living” organism and instead more like a super sophisticated robot. After all computing technology is increasing inversely to size and energy requirements. Well, not so much – silicon as a substrate is soon to reach its limits of it’s capability as a substrate for micro-processing. Moore’s Law has postulated that we could expect the number of transistors on a substrate to double every couple of years. That has happened to the point where now close to 200 million transistors can be placed on a single microchip resulting in smaller processors requiring less energy. But as size drops down to the 32 to 22 nanometer range, as it will within the next two decades, quantum effects and manufacturing technology limitations hit their bottom limit. For the trend of Moore’s law to continue, silicon must be abandoned.
It is true that silicon based computing has taken us very far. Earlier this year IBM’s “Watson”, a remarkable computer that demonstrated the ability to learn and reason, had its debut competing against two of the smartest human contestants ever to appear on the TV game show “Jeopardy”. But as sophisticated as was Watson, it was “tasked” with sole purpose of competing on a game show. Without being given a question to ponder, Watson is essentially inert – not capable of creativity, imagination or any of the other emotionally driven neural processes that make the human brain such a powerful generator of abstract ‘thought’. A computer with similar capabilities of the human brain would require a hydro dam amount of electrical energy consumption to even remotely emulate.
What works better than silicon, then? It turns out – Carbon; more specifically the carbon molecules that form the DNA molecule. DNA may be the future of computing technology that takes us beyond the limits of Moore’s Law. DNA is abundant and cheap, self replicating, consumes low amounts of energy; remarkable amounts of data can be processed in amazingly small amounts of physical space.
Though they are still in their infancy, DNA computers have been around since 1994 and have been used to solve some complex mathematical problems. These natural supercomputers already exist in our bodies; research into DNA computing promises to help us unravel both the complexity of the human brain as well as usher us into the newest realm of computer technology. With the epitaph of silicon looming on the horizon, science and industry is already working to build a more compact, efficient and accurate computer which replaces the need for electrical switching with chemical bonding.
But don’t sell your Intel stock just yet.
References and further reading:
Could Life be based on Silicon rather than Carbon?, NASA Astrobiology Institute
Where Is My Silicon-Based Life? Ask a Biogeek
Limitation Of Silicon Based Computation And Future Prospects, Shazia Hassan, Department of Computer science, The Islamia University of Bahawalpur, Punjab, Pakistan
Silicon shrinking will end about 2020, what will replace it?, Geek.Com
Is DNA Surpassing Silicon? George Klington Fernandez, St. Eugene University, Zambia