DNA: Celebrate the unknowns | Philip Ball
On the 60th anniversary of the double helix, we should admit that we don’t fully understand how evolution works at the molecular level, suggests Philip Ball.
This week’s diamond jubilee of the discovery of DNA’s molecular structure rightly celebrates how Francis Crick, James Watson and their collaborators launched the ‘genomic age’ by revealing how hereditary information is encoded in the double helix. Yet the conventional narrative — in which their 1953 Nature paper led inexorably to the Human Genome Project and the dawn of personalized medicine — is as misleading as the popular narrative of gene function itself, in which the DNA sequence is translated into proteins and ultimately into an organism’s observable characteristics, or phenotype.
Sixty years on, the very definition of ‘gene’ is hotly debated. We do not know what most of our DNA does, nor how, or to what extent it governs traits. In other words, we do not fully understand how evolution works at the molecular level.
That sounds to me like an extraordinarily exciting state of affairs, comparable perhaps to the disruptive discovery in cosmology in 1998 that the expansion of the Universe is accelerating rather than decelerating, as astronomers had believed since the late 1920s. Yet, while specialists debate what the latest findings mean, the rhetoric of popular discussions of DNA, genomics and evolution remains largely unchanged, and the public continues to be fed assurances that DNA is as solipsistic a blueprint as ever.
Question: When does life begin?
If by life you mean “human life,” this is a very complicated question that has no real answer. What you’re about to read is a combination of scientific fact and my respective interpretation of it.
Fertilization is the point at which two haploid gametes merge to become a diploid cell. This new diploid cell, or zygote, contains all the genetic material it needs to develop into a mature organism. Fertilized eggs are indeed considered living cells, so with that said, it’s not entirely unreasonable for one to infer that some sort of “life” begins there. However, all zygotes previously existed as two individual living gametes - split as an egg and a sperm before fertilization. Scientifically speaking, egg and sperm cells are living cells, so they are alive. They are not, however, in themselves humans, and thus do not constitute “human life.”
Why not? The capacity to develop into something does not constitute its existence as that thing. In biology, there are cells called “totipotent stem cells” that, given the right conditions, can develop into individual organisms. Totipotency is a complicated concept, but an example of it is cutting a piece of a plant, replanting it, and watching it grow into a brand new organism (no seed involved). While the totipotent cells involved helped make the plant cutting develop into an individual, they in themselves are not individual plants - it’s their product that is. Now, back to the zygote: a fertilized egg is classified as a totipotent stem cell, and I would say that it is no more a human being than a regular, single stem cell in your brain is your “other” brain.
That may be a bit confusing, so let me use another example – monozygotic, or identical twins. Following fertilization of an egg, there is about a 16 day period where the zygote retains its totipotency. During this time frame, if the zygote splits into two, you result in identical twins. If you classify the zygote as a human being, or introduce individuality or the concept of a “soul” to the zygote from the moment of fertilization, that would mean that a human being can be split in two, and that identical twins are the same human being. Life doesn’t work that way - it’s complicated, versatile, and most importantly, a scientific concept.
Life may seem like a magical phenomenon, but while truly beautiful, it is not magic. Two or three years ago, scientists were able to create the first self-replicating synthetic life form. That’s right – we are now in an age where humans are able to create life. As technology progresses, it is very likely that a combination of neuroscience and molecular genetics will be able to map out literally everything that you are as a human being. We’re getting to the point where there is no room for magic.
Several paragraphs later, we return to your original question. I believe that the question, “When does life begin?” is scientifically, an arbitrary question in itself – any satisfying answer would have to be philosophical in nature. Based on current biology, there is no singular definition of life - Life is more of a characteristic. The progression of a zygote into a human being is a developmental process, and there is no one point in development where we can label a blastocyst or embryo, or even fetus as an actual human being. What we can do, however, is use tangible markers such as when a fetus’ heart starts beating, or its nervous system begins to develop, or it first begins responding to external stimuli to really get a sense of what the life form really is.
Image source: The Progressive Pulse
Life is a continuation of a 3.8 billion year tradition.
Consider this, all known living organisms have DNA, and these sequences can trance our common ancestry.
YES! I have been wanting to write something like this for a while in response to scientifically-illiterate people trying to use science to argue conception begins at life. I would have also brought up chimerism, when two dizygotic twins merge, one absorbing the other and ultimately resulting in one baby. Well get that kid into jazz cuz he or she just got a double-dose of soul.
Its like seriously, when did life stop? When were oocytes and sperm considered non-living.?
It’s official: Primitive life could have lived on ancient Mars, NASA says.
A sample of Mars drilled from a rock by NASA’s Curiosity rover and then studied by onboard instruments “shows ancient Mars could have supported living microbes,” NASA officials announced today (March 12) in a statement and press conference.
The discovery comes just seven months after Curiosity landed onMars to spend at least two years determining if the planet could ever have hosted primitive life. To be clear, the new find is not evidence that Martian life has ever actually existed; Curiosity carries no life-detection instruments among its scientific gear.
“A fundamental question for this mission is whether Mars could have supported a habitable environment,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington. “From what we know now, the answer is yes.”
Curiosity drilled into a rock on Feb. 8, boring 2.5 inches (6.4 centimeters) into an outcrop called John Klein using its arm-mounted hammering drill — deeper than any robot had ever dug into the Red Planet before.
Two weeks later, the rover transferred the resulting gray powder sample into two onboard instruments called Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars, or SAM.
CheMin and SAM identified some of the key chemical ingredients for life in this dust, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, researchers said. Intriguingly, the mix also suggested a possible energy source for indigenous Martian life, if any ever existed in the area.
“The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” Paul Mahaffy, SAM principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Md., said in a statement.
A few things:
- Everyone at the beach would get sunburns. Ozone is molecular oxygen and blocks the majority of UV light. Without it, we are toast.
- The daytime sky would get darker. With fewer particles in the atmosphere to scatter blue light, the sky would get a bit less blue and a bit more black.
- Every internal combustion engine would stall. This means that every airplane taking off from a runway would likely crash to the ground, while planes in flight could glide for some time.
- All pieces of untreated metal would instantly spot-weld to one another. This is one of the more interesting side effects. The reason metals don’t weld on contact is they are coated in a layer of oxidation. In vacuum conditions, metal welds without any intermediate liquid phase ().
- Everyone’s inner ear would explode. As mentioned, we would lose about 21 percent of the air pressure in an instant, equivalent to being teleported to the top of the high Andes (elevation, about 2,000 meters).
- Every building made out of concrete would turn to dust. Oxygen is an important binder in concrete structures (really, the CO2 is), and without it, the compounds do not hold their rigidity.
- Every living cell would explode in a haze of hydrogen gas. Water is one third oxygen; without it, the hydrogen turns into gaseous state and expands in volume.
- The oceans would evaporate and bleed into space. As oxygen disappears from the oceans’ water, the hydrogen component becomes an unbound free gas. Hydrogen gas, being the lightest, will rise to the upper troposphere and slowly bleed into space through.
- Everything above ground would immediately go into free fall. As oxygen makes up about 45 percent of the Earth’s crust and mantle, there is suddenly a lot less “stuff” beneath your feet to hold everything up.
To sum, it wouldn’t be pretty.
During the past decade, astrochemists have found that DNA molecules, the fundamental building blocks of life, find their origins not on Earth, but in the Cosmos. They are the languange of the Universe —the information they inherited comes from the stars and the cosmic ecology that formed them. Scientists using the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia to study a giant cloud of gas some 25,000 light-years from Earth, near the center of our Milky Way Galaxy, have discovered a molecule thought to be a precursor to a key component of DNA and another that may have a role in the formation of the amino acid alanine.”Finding these molecules in an interstellar gas cloud means that important building blocks for DNA and amino acids can ‘seed’ newly-formed planets with the chemical precursors for life,” said Anthony Remijan, of the National Radio Astronomy Observatory (NRAO).
One of the newly-discovered molecules, called cyanomethanimine, is one step in the process that chemists believe produces adenine, one of the four nucleobases that form the “rungs” in the ladder-like structure of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, one of the twenty amino acids in the genetic code.
In each case, the newly-discovered interstellar molecules are intermediate stages in multi-step chemical processes leading to the final biological molecule. Details of the processes remain unclear, but the discoveries give new insight on where these processes occur.
Previously, scientists thought such processes took place in the very tenuous gas between the stars. The new discoveries, however, suggest that the chemical formation sequences for these molecules occurred not in gas, but on the surfaces of ice grains in interstellar space.
“We need to do further experiments to better understand how these reactions work, but it could be that some of the first key steps toward biological chemicals occurred on tiny ice grains,” Remijan said.
Fluorescence image of a neuronal culture created by stitching together six images collected at 40x magnification. Honorable Mention, 2011 Olympus BioScapes Digital Imaging Competition®.
“Weird Life”: The Story of the Cell
“The synthesis of life, should it ever occur, will not be the sensational discovery which we usually associate with the idea. If we accept the theory of evolution, then the first dawn of the synthesis of life must consist in the production of forms intermediate between the inorganic and the organic world, forms which possess only some of the rudimentary attributes of life, to which other attributes will be slowly added in the course of development by the evolutionary action of the environment.” - Stephane Leduc, 1911
In July 2007, a group of scientists associated with the American Research Council issued a report about something they termed “weird life.” Weird life, they said, could be life in a form that we have never seen before - an organism may not depend on water, for example, or it may have a completely different, non-nucleic-acid based system of heredity and still be alive. Their definition of weird life was vague, and not by accident: One of the primary challenges in the discussion of life, both on earth and elsewhere in the universe, is that life itself is a very difficult thing to parameterise. As David Greer, a professor of physics at New York University, says, “There is no mathematically rigorous definition of life.” Our determination of life is based entirely on our own human experience, and thus its working definition is less a set of functional rules for classification and more a set of somewhat ambiguous statements designed to organise the unknown. The precise problem with trying to organise the unknown, of course, is that nothing is known about it; but without a reconcilable definition of life - or “weird life”, as the case may be - we don’t even know where to start looking.
The key, I think, to this almost certainly inaccurate (and definitely not mathematically rigorous) but working definition is to explore how life came about in the first place. This serves two purposes: First, the definition of life could arguably be based on the most basic conditions necessary for it to occur, and second, life in its most rudimentary forms are more likely to be homogenous across biological systems (however more complex or different from our own) than the large-scale plants and animals we traditionally associate with life. In addition, the makeshift definition should be written as a set of provable postulates, and should be sufficiently inclusive to potentially apply to all forms of aptly labeled “weird life” without being overly promiscuous, so to speak.
The Primordial Soup’s Gone Off
Ever since Stanley Miller’s infamous experiment in 1953, the long-time leading hypothesis into the origin of life was his theory, built around the reducing atmospheric gases of early earth and electric charge passing through them in the form of lightning. Miller’s experiment, which has been replicated, successfully showed that shooting a spark through reducing gases in a laboratory beaker produces biomolecules - in Miller’s case, approximately 10 amino acids and several nucleic acid precursors, although others who have repeated the experiment have had rather more success. The experiment illustrates clearly that life could have begun this way.
Of course, the origin of life is still a black box; in reality any number of plausible hypotheses could be correct. However, for me there are several unaddressed issues in Miller’s experiment that make me skeptical that it is the whole story behind the evolution of us. The primary issue is simply time; the earth is only 4.5 billion years old, and the oldest microfossils of early cell-like structures that have been found date back 3.5 billion years. While a billion years seems like - well, a billion years to us, it’s actually quite quick on an evolutionary timescale. To me, this means that life didn’t simply come down to a lucky lightning strike - it indicates that there was a driving force behind its development that pushed it forward faster.
In 1993, a different theory for the origin of life - termed the hydrothermal vent idea - came into prevalence. It suggested that instead of a collection of atoms in the early ocean, life came out of deep-sea hydrothermal vents. There is much compelling evidence for this idea; two of the most compelling bits, I think, are the existence of an energy disequilibrium and the interconnected micropores found on the vents’ surface.
The ocean, even on the early earth, was a fairly stagnant place in terms of energy gradients; lightning strikes could perhaps have caused them sporadically, but in different locations and to varying degrees with very little continuity. Hydrothermal vents, on the other hand, are rich in energy disequilibrium, boasting temperature, pH, and redox gradients.
So why are energy gradients so important? Because for cells, harnessing energy as ion gradients is about as universal as the genetic code. A new paper recently published in Cell postulates that tiny micropores found on the surface of deep-sea vents - conveniently approximately the diameter of a cell - could have been the starting point of life on earth. In modern cells, about 75% of a cell’s ATP budget - or biological energy - goes into making proteins; conversely, ATP is replenished by proteins that harness chemiosmotic gradients. The paper postulates that the energy disequilibrium provided by hydrothermal vents - specifically, that sustained disequilibrium at a submarine hydrothermal vent interfacing with ocean water - generates conditions that thermodynamically favour the formation of life’s building blocks, particularly amino acids, in the presence of hydrogen gas, carbon dioxide, and ammonium. If a leaky membrane built of lipid precursors accumulated near a vent, the budding system would have a ready-made metabolism by exploiting the pre-existing chemiosmotic gradient. Once enough precursors accumulated, and the “metabolism tap” was shut off due to the newly formed “membrane“‘s impermeability, natural selection would strongly favour cells with simple antiporters that could continue to exploit the ion gradient.
Defining Life from Vents
If, for the sake of argument, the thermal vent hypothesis is found to be the way things actually were, what then? What about life? Defining life by the characteristics of the first cell does not appeal to me; this leads to a definition of characteristics that are shared because they originate from a common ancestor, and not because they are actually fundamental to life. However, the hydrothermal vent hypothesis does, I think, enhance our understanding of what is needed for life, at least on this planet, and based upon the need for a biochemical gradient for protein production and the necessity of a lineage to exploit progress made in the previous generation, I would define life as:
- A physical compartment across the walls of which energy can be generated and utilised for biochemical reactions, and;
- one that possesses a material of heredity that may be passed to the next generation.
It’s not a particularly restrictive definition, nor is it likely broadly accurate. However, the fact remains that there are many definitions of life; few widely agreed upon, and certainly none reasonably consented to in their entirety without special cases. Considering what was necessary for the first cell to form is as valid a method of organising the unknown as any other, and perhaps, one day, we’ll be able to find a distinctly new organism somewhere in the universe, one that shifts our entire paradigm on biochemistry, heredity, and what it means to fundamentally be alive. Until then, I think, formal and constructive definitions will elude us, and “weird life” will continue to be - well, weird.
An Afterthought: The Interesting Case of Protocells
In his TedX talk, Martin Hanczyc outlined a very similar definition of life to the one I derived from the assumed origin of life inside thermal vents. It can be reasonably summarised in three words:
He works extensively with oil and water systems, designing in vitro protocells. He also works with tar systems to simulate the stuff of the early universe, like those in the images at the top of this post; his protocells are comprised of single-digit numbers of chemicals, and yet are able to locate food, respond to one another within an environment, and even divide and hybridise into wholly new organisms with new functional characteristics.
So are these protocells alive? Martin Hanczyc believes that nothing can be considered “alive” in a black-and-white way; rather, these protocells fall somewhere in the range of an intermediate between the inorganic and organic world, and while they possess some attributes necessary for life they simply fall on a continuum along with humankind and this desk. A video of his TedX talk, in which he explains further, can be found here.
Due to its length and their quantity, references in this post are cited using links where they are most relevant. Most of the information used comes from a new paper in Cell on the Origin of Membrane Bioenergetics (Martin and Lane, 2012), and Martin Hancycz’s TedX talk. For another take on Martin Hancycz’s work, see this post here.
First Image : A Hubble Space Telescope image of Dark Matter mapped in a 3d representation.
Second Image: Abel 1689 galaxy cluster.
Dark matter makes up the majority of mass in our universe. However, we cannot directly measure the stuff as it doesn’t interact with electromagnetic radiation (i.e. it doesn’t emit or reflect any light), but we can indirectly observe its presence. In the Hubble Space Telescope image above, the distribution of mostly dark matter has been calculated and mapped. Basically, the location and density of anything with mass has been plotted in a 3D representation of the cosmos.
A 2011 study suggests that mysterious, invisible dark matter could warm millions of starless planets in regions such as Abell 1689 (image below) and make them habitable.
Scientists think the invisible, as-yet-unidentified dark matter which we know exists because of the gravitational effects it has on galaxies, makes up about 85 percent of all matter in the universe. Current prime candidates for what dark matter might be are massive particles that only rarely interact with normal matter.These particles could be their own antiparticles, meaning they annihilate each other when they meet, releasing energy. These invisible particles could get captured by a planet’s gravity and unleash energy that could warm that world, according to physicist Dan Hooper and astrophysicist Jason Steffen at the Fermi National Accelerator Laboratory.Hooper and Steffen’s propose that rocky “super-Earths” in regions with high densities of slow-moving dark matter could be warmed enough to keep liquid water on their surfaces, even in the absence of additional energy from starlight or other sources.The density of dark matter is expected to be hundreds to thousands of times greater in the innermost regions of the Milky Way and in the cores of dwarf spheroidal galaxies than it is in our solar system.
The scientists concluded that on planets in dense “dark-matter” regions, it may be dark matter rather than light that creates the basic elements you need for organic life without a star”
The Phylogenetic ’Tree of Life’
Charles Darwin proposed that phylogeny, the evolutionary relatedness among species through time, was expressible as a metaphor he termed the Tree of Life. The modern development of this idea is called the Phylogenetic tree.
A nice video showing the transcription of DNA to mRNA by RNA-polymerase. A messenger RNA transcript then exists the nucleus to find a ribosome. Their is it translated into a primary structure polynucleotide. Chaperonin fold proteins with the use of ATP into secondary and tertiary structures. Once realised from the chaperonin the protein may be complete or join part of a quaternary structure.
Passwords will be obsolete. IBM says it will happen in five years. Who are we to disagree? Apple and Google are designing face-recognition software for cellphones. DARPA is researching the dynamics of keystrokes. Others are looking into retinal scans, voiceprints, and heartbeats.
Drones will protect endangered species. Guarding at-risk animals from poachers with foot patrols is expensive and dangerous. This summer rangers in Nepal’s Chitwan National Park previewed a savvy solution: Hand-launched drones armed with cameras and GPS provided aerial surveillance of threatened Indian rhinos.
Vegetarians and carnivores will dine together on synthetic meats. We’re not talking about tofu. We’re talking about nutritious, low-cost substitutes that look and taste just like the real thing. Twitter co-founder Biz Stone has already invested in Beyond Meat, which makes plant-based chicken strips so convincing they almost fooled New York Times food writer Mark Bittman.
Contact lenses will grant us Terminator vision. When miniaturization reaches its full potential, achieving superhuman eyesight will be as simple as placing a soft lens on your eye. Early prototypes feature wirelessly powered LEDs. But circuits and antennas can also be grafted onto flexible polymer, enabling zooming, night vision, and visible data fields.
All 130 million books on the planet will be digitized. In 2010 Google planned to complete the job by decade’s end, but as of March it still had 110 million tomes to go, so we’re adding wiggle room. You might use the time to shop for storage, because given today’s options and the average size of an e-book (3 MB), you’ll need 124 3-terabyte drives to carry the library of humanity with you. It won’t fit into a backpack, but it’s small enough to schlep in a hockey bag.
The refrigerator will place your grocery order.
The carpet will detect intruders and summon help if you fall.
Lawn sensors will tell you which part of your yard to fertilize.
The electric meter will monitor local power consumption and help you make full use of off-peak rates.
An ion engine will reach the stars. If you’re thinking of making the trip to Alpha Centauri, pack plenty of snacks. At 25.8 trillion miles, the voyage requires more than four years of travel at light speed, and you won’t be going nearly that fast. To complete the journey, you’ll have to rely on a scaled-up version of the engine on the Deep Space 1 probe, launched in 1998. Instead of liquid or solid fuel, the craft was propelled by ions of xenon gas accelerated by an electric field.
Scientists will map the quadrillion connections between the brain’s neurons. Quadrillion sounds like a made-up number, but we assure you it’s real. Those connections hold the answers to questions about mental illness, learning, and the whole nature versus nurture issue. If every one of them were a penny, you could stack them and build a tower 963 million miles high. It would stretch past Mars, Jupiter, and Saturn and stop roughly halfway to Uranus.
THE PM BRAIN TRUST SAYS:
WITHIN 20 YEARS…
Self-driving cars will hit the mainstream market.
Battles will be waged without direct human participation (think robots or unmanned aerial vehicles).
The first fully functional brain-controlled bionic limb will arrive.
WITHIN 30 YEARS…
All-purpose robots will help us with household chores.
Space travel will become as affordable as a round-the-world plane ticket.
Soldiers will use exoskeletons to enhance battlefield performance.
WITHIN 40 YEARS…
Nanobots will perform medical procedures inside our bodies.
WITHIN 50 YEARS…
We will have a colony on Mars.
Doctors will successfully transplant a lab-grown human heart.
We will fly the friendly skies without pilots onboard.
And renewable energy sources will surpass fossil fuels in electricity generation.
WITHIN 60 YEARS…
Digital data (texts, songs, etc.) will be zapped directly into our brains.
We will activate the first fusion power plant.
And we will wage the first battle in space.
WITHIN 100 YEARS…
The last gasoline-powered car will come off the assembly line.
Land creatures might not have come from the sea
Cartoonists have found many clever ways to depict the conventional wisdom that complex life evolved in the sea and then crawled up onto land. But a provocative new study suggests that the procession might be drawn in the wrong direction. The earliest large life forms may have appeared on land long before the oceans filled with creatures that swam and crawled and burrowed in the mud.
This story is told from fossils that date from before an extraordinary period in Earth history, called the Cambrian explosion, about 530 million years ago. That’s when complex life suddenly burst forth and filled the seas with a panoply of life forms.
Paleontologists have found fossil evidence for a scattering of fossil animals that predate that historic moment. These mysterious organisms are called Ediacarans. Many scientists have assumed Ediacarans were predecessors of jellyfish, worms and other invertebrates. But Greg Retallack at the University of Oregon says he always had his doubts.
Retallack has been building the case that Ediacarans weren’t in fact animals, but actually more like fungi or lichens. And if that idea weren’t enough of a departure from standard theory, he now argues in a paper in the journal Nature that Ediacarans weren’t even living in the sea, as everyone has assumed. He says he has reanalyzed some Australian rock where they’re found and concluded that it’s ancient soil, not marine mud.
These early life forms were landlubbers.
“What I’m saying for the Ediacaran is that the big [life] forms were on land and life was actually quite a bit simpler in the ocean,” Retallack says.
So does that suggest life evolved on land and moved into the ocean? “Yes, in a nutshell,” he says.
Paul Knauth at Arizona State University has been pondering this same possibility. “I don’t have any problem with early evolution being primarily on land,” says Knauth, a professor in the School of Earth and Space Exploration at Arizona State University. “I think you can make a pretty good argument for that, and that it came into the sea later. It’s kind of a radical idea, but the fact is we don’t know.”
Knauth says it could help explain why the Cambrian explosion appears to be so rapid. It’s possible these many life forms gradually evolved on the land and then made a quick dash to the sea.
And, he adds, “that means that the Earth was not a barren land surface until about 500 million years ago, as a lot of people have speculated.”
The new analysis of the Ediacaran fossils is at least a hint that this could be right. But of course if you’re a scientist making an extraordinary claim, you need to back it up with extraordinary evidence.
“To me the evidence is not a slam-dunk,” says Shuhai Xiao, at Virginia Tech. He argues, among other things, that the same Ediacaran species found in what is arguably soil is also found in deposits that he says were ocean sediments.
That would imply that the same species would be able to live both on dry land and under a salty ocean. Xiao finds that unlikely. “It’s pretty hard for the same species to be able to live in both environments.”
So he is not convinced that Retallack is really looking at fossils in terrestrial soil. And so begins a sharp academic debate.
Xiao is far from alone in his skepticism. The current ideas have many defenders. Retallack seems to relish the controversy. He knows what he’s in for.
“The idea that Ediacaran fossils were marine invertebrates is so deeply entrenched, it’s in all the textbooks,” he says. When someone (namely him) comes along and says that’s not so, “it’s going to be treated like a death in the family. It’s going to go through all the phases of grief, starting with denial.”
It remains to be seen whether the story ends with acceptance of Retallack’s provocative proposal.
The popular film trilogy, The Matrix, presented a cyberuniverse where humans live in a simulated reality created by sentient machines.
Now, a philosopher and team of physicists imagine that we might really be living inside a computer-generated universe that you could call The Lattice. What’s more, we may be able to detect it.
In 2003, British philosopher Nick Bostrom published a paper that proposed the universe we live in might in fact really be a numerical computer simulation. To give this a bizarre Twilight Zone twist, he suggested that our far-evolved distant descendants might construct such a program to simulate the past and recreate how their remote ancestors lived.
He felt that such an experiment was inevitable for a supercivilization. If it didn’t happen by now, then in meant that humanity never evolved that far and we’re doomed to a short lifespan as a species, he argued.
To extrapolate further, I’d suggest that artificial intelligent entities descended from us would be curious about looking back in time by simulating the universe of their biological ancestors.
As off-the-wall as this sounds, a team of physicists at the University of Washington (UW) recently announced that there is a potential test to seen if we actually live in The Lattice. Ironically, it would be the first such observation for scientifically hypothesized evidence of intelligent design behind the cosmos.
The UW team too propose that super-intelligent entities, bored with their current universe, do numerical simulations to explore all possibilities in the landscape of the underlying quantum vacuum (from which the big bang percolated) through universe simulations. “This is perhaps the most profound quest that can be undertaken by a sentient being,” write the authors.
Before you dismiss this idea as completely loony, the reality of such a Sim Universe might solve a lot of eerie mysteries about the cosmos. About two-dozen of the universe’s fundamental constants happen to fall within the narrow range thought to be compatible with life. At first glance it seems as unlikely as balancing a pencil on its tip. Jiggle these parameters and life as we know it would have never appeared. Not even stars and galaxies. This is called the Anthropic principle.
The discovery of dark energy over a decade ago further compounds the universe’s strangeness. This sort of “antigravity” pushing space-time apart is the closest thing there is to nothing and still is something. This energy from the vacuum of space is 60 orders of magnitude weaker that what would be predicted by quantum physics.The eminent cosmologist Michael Turner ranks dark energy as “the most profound mystery in all of science.”
We are also living at a very special time in the universe’s history where it switched gears from decelerating to accelerating under the push of dark energy. This begs the question “why me why now?” (A phrase popularly attributed to Olympic figure skater Nancy Kerrigan in 1994 when she was attacked and crippled by an opponent.)
If dark energy were slightly stronger the universe would have blown apart before stars formed. Any weaker and the universe would have imploded long ago. Its incredibly anemic value has been seen as circumstantial evidence for parallel universes with their own flavor of dark energy that is typically destructive. It’s as if our universe won the lottery and got all the physical parameters just right for us to exist.
Finally, an artificial universe solves the Fermi Paradox (where are all the space aliens?) by implying that we truly are alone in the universe. It was custom made for us by our far-future progeny.
Biblical creationists can no doubt embrace these seeming cosmic coincidences as unequivocal evidence for their “theory” of Intelligent Design (ID). But is our “God” really a computer programmer rather than a bearded old man living in the sky?
Currently, supercomputers using a impressive-sounding technique called lattice quantum chromodynamics, and starting from the fundamental physical laws, can simulate only a very small portion of the universe. The scale is a little larger than the nucleus of an atom, according UW physicist Martin Savage. Mega-computers of the far future could greatly expand the size of the Sim Universe.
If we are living in such a program, there could be telltale evidence for the underlying lattice used in modeling the space-time continuum, say the researchers. This signature could show up as a limitation in the energy of cosmic rays. They would travel diagonally across the model universe and not interact equally in all directions, as they otherwise would be expected to do according to present cosmology.
If such results were measured, physicists would have to rule out any and all other natural explanations for the anomaly before flirting with the idea of intelligent design. (To avoid confusion with the purely faith-based creationist ID, this would not prove the existence of a biblical God, because you’d have to ask the question “why does God need a lattice?”)
If our universe is a simulation, then those entities controlling it could be running other simulations as well to create other universes parallel to our own. No doubt this would call for, ahem, massive parallel processing.
If all of this isn’t mind-blowing enough, Bostrom imagined “stacked” levels of reality, “we would have to suspect that the post-humans running our simulation are themselves simulated beings; and their creators, in turn, may also be simulated beings. Here may be room for a large number of levels of reality, and the number could be increasing over time.”
To compound this even further, Bostrom imagined a hierarchy of deities, “In some ways, the post-humans running a simulation are like gods. However, all the demigods except those at the fundamental level of reality are subject to sanctions by the more powerful gods living at lower levels.”
If the parallel universes are all running on the same computer platform could we communicate with them? If so, I hope the Matrix’s manic Agent Smith doesn’t materialize one day.
To borrow from the title of Isaac Asimov’s novel I Robot, the human condition might be described as I Subroutine.