The Singularity Is Near: When Humans Transcend Biology (63 page)

f
_l
:
For the planets
capable
of sustaining life, on what fraction of these does life actually evolve? Estimates are all over the map, from approximately 100 percent to about 0 percent.

f
_i
:
For each planet on which life evolves, what is the fraction on which intelligent life evolves?
f
_l
and
f
_i
are the most controversial factors in the Drake equation. Here again, estimates range from nearly 100 percent (that is, once life gets a foothold, intelligent life is sure to follow) to close to 0 percent (that is, intelligent life is very rare).

f
_c
:
For each planet with intelligent life, what is the fraction that communicates with radio waves? The estimates for
f
_c
tend to be higher than for
f
_l
and
f
_i
, based on the (sensible) reasoning that once you have an intelligent species, the discovery and use of radio communication is likely.

f
_L
= the fraction of the universe’s life during which an average communicating civilization communicates with radio waves.
⁶⁹
If we take our civilization as an example, we have been communicating with radio transmissions for about one hundred years out of the roughly ten- to twenty-billion-year history of the universe, so
f
_L
for the Earth is about 10
^-8
so far. If we continue communicating with radio waves for, say, another nine hundred years, the factor would then be 10
^-7
. This factor is affected by a number of considerations. If a civilization
destroys itself because it is unable to handle the destructive power of technologies that may tend to develop along with radio communication (such as nuclear fusion or self-replicating nanotechnology), then radio transmissions would cease. We have seen civilizations on Earth (the Mayans, for example) suddenly end their organized societies and scientific pursuits (although preradio). On the other hand it seems unlikely that every civilization would end this way, so sudden destruction is likely to be only a modest factor in reducing the number of radio-capable civilizations.

A more salient issue is that of civilizations progressing from electromagnetic (that is, radio) transmissions to more capable means of communicating. Here on Earth we are rapidly moving from radio transmissions to wires, using cable and fiber optics for long-distance communication. So despite enormous increases in overall communication bandwidth, the amount of electromagnetic information sent into space from our planet has nevertheless remained fairly steady for the past decade. On the other hand we do have increasing means of wireless communication (for example, cell phones and new wireless Internet protocols, such as the emerging Wimax standard). Rather than use wires, communication may rely on exotic mediums such as gravity waves. However, even in this case, although the electromagnetic means of communication may no longer be the cutting edge of an ETI’s communication technology, it is likely to continue to be used for at least some applications (in any case,
f
_L
does take into consideration the possibility that a civilization would stop such transmissions).

It is clear that the Drake equation contains many imponderables. Many SETI advocates who have studied it carefully argue that it implies that there must be significant numbers of radio-transmitting civilizations in our galaxy alone. For example, if we assume that 50 percent of the stars have planets (
f
_p
= 0.5), that each of these stars has an average of two planets able to sustain life (
n
_e
= 2), that on half of these planets life has actually evolved (
f
_l
= 0.5), that half of these planets has evolved intelligent life (
f
_i
= 0.5), that half of these are radio-capable (
f
_c
= 0.5), and that the average radio-capable civilization has been broadcasting for one million years (
f
_L
= 10
^-4
), the Drake equation tells us that there are 1,250,000 radio-capable civilizations in our galaxy. For example, the SETI Institute’s senior astronomer, Seth Shostak, estimates that there are between ten thousand and one million planets in the Milky Way containing a radio-broadcasting civilization.
⁷⁰
Carl Sagan estimated around a million in the galaxy, and Drake estimated around ten thousand.
⁷¹

But the parameters above are arguably very high. If we make more conservative
assumptions on the difficulty of evolving life—and intelligent life in particular—we get a very different outcome. If we assume that 50 percent of the stars have planets (
f
_p
= 0.5), that only one tenth of these stars have planets able to sustain life (
n
_e
= 0.1 based on the observation that life-supporting conditions are not that prevalent), that on 1 percent of these planets life has actually evolved (
f
_l
= 0.01 based on the difficulty of life starting on a planet), that 5 percent of these life-evolving planets have evolved intelligent life (
f
_i
= 0.05, based on the very long period of time this took on Earth), that half of these are radio-capable (
f
_c
= 0.5), and that the average radio-capable civilization has been broadcasting for ten thousand years (
f
_L
= 10
^-6
), the Drake equation tells us that there is about one (1.25 to be exact) radio-capable civilization in the Milky Way. And we already know of one.

In the end, it is difficult to make a strong argument for or against ETI based on this equation. If the Drake formula tells us anything, it is the extreme uncertainty of our estimates. What we do know for now, however, is that the cosmos appears silent—that is, we’ve detected no convincing evidence of ETI transmissions. The assumption behind SETI is that life—and intelligent life—is so prevalent that there must be millions if not billions of radio-capable civilizations in the universe (or at least within our light sphere, which refers to radio-broadcasting civilizations that were sending out radio waves early enough to reach Earth by today). Not a single one of them, however, has made itself noticeable to our SETI efforts thus far. So let’s consider the basic SETI assumption regarding the number of radio-capable civilizations from the perspective of the law of accelerating returns. As we have discussed, an evolutionary process inherently accelerates. Moreover, the evolution of technology is far faster than the relatively slow evolutionary process that gives rise to a technology-creating species in the first place. In our own case we went from a pre-electricity, computerless society that used horses as its fastest land-based transportation to the sophisticated computational and communications technologies we have today in only two hundred years. My projections show, as noted above, that within another century we will multiply our intelligence by trillions of trillions. So only three hundred years will have been necessary to take us from the early stirrings of primitive mechanical technologies to a vast expansion of our intelligence and ability to communicate. Thus, once a species creates electronics and sufficiently advanced technology to beam radio transmissions, it is only a matter of a modest number of centuries for it to vastly expand the powers of its intelligence.

The three centuries this will have taken on Earth is an extremely brief period of time on a cosmological scale, given that the age of the universe is estimated at thirteen to fourteen billion years.
⁷²
My model implies that once a
civilization achieves our own level of radio transmission, it takes no more than a century—two at the most—to achieve a type II civilization. If we accept the underlying SETI assumption that there are many thousands if not millions of radio-capable civilizations in our galaxy—and therefore billions within our light sphere in the universe—these civilizations must exist in different stages over billions of years of development. Some would be behind us, and some would be ahead. It is not credible that every single one of the civilizations that are more advanced than us is going to be only a few decades ahead. Most of those that are ahead of us would be ahead by millions, if not billions, of years.

Yet since a period of only a few centuries is sufficient to progress from mechanical technology to the vast explosion of intelligence and communication of the Singularity, under the SETI assumption there should be billions of civilizations in our light sphere (thousands or millions in our galaxy) whose technology is ahead of ours to an unimaginable degree. In at least some discussions of the SETI project, we see the same kind of linear thinking that permeates every other field, assumptions that civilizations will reach our level of technology, and that technology will progress from that point very gradually for thousands if not millions of years. Yet the jump from the first stirrings of radio to powers that go beyond a mere type II civilization takes only a few hundred years. So the skies should be ablaze with intelligent transmissions.

Yet the skies are quiet. It is odd and intriguing that we find the cosmos so silent. As Enrico Fermi asked in the summer of 1950, “Where is everybody?”
⁷³
A sufficiently advanced civilization would not be likely to restrict its transmissions to subtle signals on obscure frequencies. Why are all the ETIs so shy?

There have been attempts to respond to the so-called Fermi Paradox (which, granted, is a paradox only if one accepts the optimistic parameters that most observers apply to the Drake equation). One common response is that a civilization may obliterate itself once it reaches radio capability. This explanation might be acceptable if we were talking about only a few such civilizations, but with the common SETI assumptions implying billions of them, it is not credible to believe that every one of them destroyed itself.

Other arguments run along this same line. Perhaps “they” have decided not to disturb us (given how primitive we are) and are just watching us quietly (an ethical guideline that will be familiar to
Star Trek
fans). Again, it is hard to believe that every such civilization out of the billions that should exist has made the same decision. Or, perhaps, they have moved on to more capable communication paradigms. I do believe that more capable communication methods than electromagnetic waves—even very high-frequency ones—are likely to be feasible and that an advanced civilization (such as we will become
over the next century) is likely to discover and exploit them. But it is very unlikely that there would be absolutely no role left for electromagnetic waves, even as a by-product of other technological processes, in any of these many millions of civilizations.

Incidentally, this is not an argument against the value of the SETI project, which should have high priority, because the negative finding is no less important than a positive result.

The Limits of Computation Revisited.
Let’s consider some additional implications of the law of accelerating returns to intelligence in the cosmos. In
chapter 3
I discussed the ultimate cold laptop and estimated the optimal computational capacity of a one-liter, one-kilogram computer at around 10
⁴²
cps, which is sufficient to perform the equivalent of ten thousand years of the thinking of ten billion human brains in ten microseconds. If we allow more intelligent management of energy and heat, the potential in one kilogram of matter to compute may be as high as 10
⁵⁰
cps.

The technical requirements to achieve computational capacities in this range are daunting, but as I pointed out, the appropriate mental experiment is to consider the vast engineering ability of a civilization with 10
⁴²
cps per kilogram, not the limited engineering ability of humans today. A civilization at 10
⁴²
cps is likely to figure out how to get to 10
⁴³
cps and then to 10
⁴⁴
and so on. (Indeed, we can make the same argument at each step to get to the next.)

Once civilization reaches these levels it is obviously not going to restrict its computation to one kilogram of matter, any more than we do so today. Let’s consider what our civilization can accomplish with the mass and energy in our own vicinity. The Earth contains a mass of about 6 × 10
²⁴
kilograms. Jupiter has a mass of about 1.9 × 10
²⁷
kilograms. If we ignore the hydrogen and helium, we have about 1.7 × 10
²⁶
kilograms of matter in the solar system, not including the sun (which ultimately is also fair game). The overall solar system, which is dominated by the sun, has a mass of about 2 × 10
³⁰
kilograms. As a crude upper-bound analysis, if we apply the mass in the solar system to our 10
⁵⁰
estimate of the limit of computational capacity per kilogram of matter (based on the limits for nanocomputing), we get a limit of 10
⁸⁰
cps for computation in our “vicinity.”

Obviously, there are practical considerations that are likely to provide difficulty in reaching this kind of upper limit. But even if we devoted one twentieth of 1 percent (0.0005) of the matter of the solar system to computational and communication resources, we get capacities of 10
⁶⁹
cps for “cold” computing and 10
⁷⁷
cps for “hot” computing.
⁷⁴

Engineering estimates have been made for computing at these scales that take into consideration complex design requirements such as energy usage, heat dissipation, internal communication speeds, the composition of matter in the solar system, and many other factors. These designs use reversible computing, but as I pointed out in
chapter 3
, we still need to consider the energy requirements for correcting errors and communicating results. In an analysis by computational neuroscientist Anders Sandberg, the computational capacity of an Earth-size computational “object” called Zeus was reviewed.
⁷⁵
The conceptual design of this “cold” computer, consisting of about 10
²⁵
kilograms of carbon (about 1.8 times the mass of the Earth) in the form of diamondoid consists of 5 × 10
³⁷
computational nodes, each of which uses extensive parallel processing. Zeus provides an estimated peak of 10
⁶¹
cps of computation or, if used for data storage, 10
⁴⁷
bits. A primary limiting factor for the design is the number of bit erasures permitted (it allows up to 2.6 × 10
³²
bit erasures per second), which are primarily used to correct errors from cosmic rays and quantum effects.