Dear Ananjit Chander:
Regards your questions.
First of you need to me more specific in your question 1. What type and kinds of control are you seeking?
A vision shared by most researchers in complex systems is that certain intrinsic, perhaps even universal features capture fundamental aspects of complexity in a manner which transcends specific domains.
It is in identifying these features that differences arise. In disciplines such as physics, biology, engineering, sociology, economics, and ecology, individual complex systems are necessarily the objects of study, but there often seems to be little common ground between their models, abstractions, and methods.
Highly Optimized Tolerance (HOT) is a recent attempt to develop a general framework for studying complexity, which was introduced by Carlson and Doyle. The HOT view is motivated by examples from biology and engineering, and builds theoretically on the abstractions from control, communications, and computing. A central component of our research program involves extending this theoretical framework.
HOT emphasizes 1) highly structured, non-generic, self-dissimilar internal configurations and 2) robust, yet fragile external behavior. In HOT these features are inherent, important features of complexity, not accidents of evolution or artifices of engineering design, but rather inevitably intertwined and mutually reinforcing. HOT provides an appealing base for the development of a general framework for understanding a broad spectrum of complex systems. Questions related to robustness, diversity, predictability, verifiability, and evolvability arise in a wide range of disciplines, and demand sharper definitions, and new tools for analysis. The success of HOT came from first studying tractable, broadly accessible models, from which we extract qualitative insights and quantitative analysis which can be applied to specific problems.
blends the perspectives of engineering control theory with the simple models of statistical physics. While physics focuses primarily on universal properties of generic ensembles of isolated systems, control theory studies open systems in terms of their input vs. output characteristics, and has the flexibility to describe systems which are highly structured and extremely non-generic in a systematic way. Currently, we are moving further in developing links between the mathematics of control theory and fundamental problems in statistical physics by using model reduction on finite time horizons to derive rigorous links between statistical physics, thermodynamics, and measurement. Model Reduction
and other mathematical methods have been developed with precision in control theory, but their consequences outside of that discipline are largely unexplored. Many of these methods when properly generalized will become the building blocks for quantitative analysis of complex systems across a broad range of disciplines.
Even within statistical physics and quantum theory there are situations where mathematics from control theory can lead to a more rigorous theoretical foundation. This is particularly true where the coupling between a system and the environment must be explicitly taken into account, as in the case of dissipation and quantum measurement. The opportunities for developing a more quantitative theoretical foundation which extends to other disciplines is extremely promising. In areas such as biology, ecology, sociology, and finance, systems are necessarily open, highly structured, and involve a great deal of feedback, so they are clear candidates for methodologies from controls.
Your question 2 on a nuclear reactor powerful enough to sustain a controlled fusion reaction?
First of all, you must realize the difference between nuclear fission, which is controlled in a nuclear reactor, and nuclear fusion, which is produced within an intense magnetic field necessary to contain the extremely high temperatures involved in the fusion process.
Containing nuclear fusion requires immense amounts of electric power to provide energy for the massive magnets necessary to confine the heated plasma within a fusion reactor.
The Joint European Torus (JET) consumes large amounts of power – for fusion to occur we need to create and maintain plasma at extremely high temperatures. Additionally we need to contain the plasma by energising large magnetic coils. In total, when JET runs, it consumes 700 – 800 MW of electrical power (the equivalent of 1-2% of the United Kingdom’s total electricity usage!).
Future reactors will use superconducting magnetic coils, which are much more efficient, so they will not expect to use so much power – maybe 200-300 MW of electrical power. They will produce 1-2GW (1000 – 2000 MW) of electricity, whereas JET does not have the set up to harvest any energy produced, as it is not a power reactor, but an experiment designed to investigate the containment of the fusion process.
The power required to keep a fusion reactor working is an interesting question. Energy input is required to keep the plasma hot, because most of the energy produced by fusion is carried away by the neutrons. However 20% is carried by the helium nuclei, which remain within the plasma, so it is possible to reach a point called ignition, at which the production of hot helium is enough to sustain the plasma and the external energy sources can be turned off. It is not clear yet however whether that will be the optimum operating regime in a power plant – being slightly below ignition may give better control of the reactor (while still producing plenty of hot neutrons).
Unit 4 of the Beloyarsk nuclear power plant, Russia's BN-800 reactor, has been connected to the grid and resumed operations upon completion of scheduled maintenance. For the first time the refuelling has been carried out with uranium-plutonium fuel only.
Distinct from traditional nuclear fuel with enriched uranium, mixed oxide (MOX) fuel pellets are based on the mix of nuclear fuel cycle derivatives, such as oxide of plutonium bred in commercial reactors, and oxide of depleted uranium which comes from defluorination of depleted uranium hexafluoride (UF6), the so-called secondary tailings of uranium enrichment facilities.
As of 2021, the first batch of 18 MOX fuel assemblies was loaded into the BN-800 reactor core in January 2020, and now 160 assemblies more with fresh MOX fuel have been added. These replace the fuel assemblies with enriched uranium. Thus, the BN-800 core is now one-third filled with MOX fuel. From now on, only MOX fuel will be loaded into this reactor.
The development moves the Beloyarsk plant a step closer to Rosatom's strategic goal to close the nuclear fuel cycle, Ivan Sidorov, director of Beloyarsk NPP, said.
"This means that using MOX fuel will make it possible to involve the uranium that is not currently used in the fuel manufacturing and expand the resource feed-stock of the nuclear power industry. In addition, the BN-800 reactor can re-use spent nuclear fuel from other nuclear power plants and minimise radioactive waste by 'afterburning' long-lived isotopes from them. Taking into account the schedule, we will be able to switch to the core fully loaded with MOX fuel as early as 2022,” he said.
The fuel assemblies were manufactured at the Mining and Chemical Combine (MCC), in Zheleznogorsk, in the Krasnoyarsk region of Russia.
Russia's BN-800 nuclear reactor produces some 880 MW of electric power, which is sufficient to power the JET fusion reactor alone. It is reported to be one of the largest fission reactors.
Your question 3, on Albert's river of time and the multiverse. Do you mean Albert Einstein? This needs to be made clear.
When it comes to time, Einstein refers to the fact that the equations of physics show no preference for some mysterious moment now
; rather, all moments in time exist equally. Emphasizing this fact, these equations work equally well in one direction of time—from the past to the future—as they do in the opposite direction—from the future to the past. The present moment, from this perspective, has no unique or special importance—it is merely an arbitrary dividing line between the past and the future.
More specifically, Einstein’s own theory of relativity demands
the equal existence of the past, the present and the future. As he elaborated elsewhere, in more technical language: “The four-dimensional continuum is now no longer resolvable objectively into sections, all of which contain simultaneous events; “now” loses for the spatially extended world its objective meaning. It is because of this that space and time must be regarded as a four-dimensional continuum that is objectively unresolvable.” He adds, “It appears therefore more natural to think of physical reality as a four-dimensional existence, instead of, as hitherto, the evolution
of a three-dimensional existence.”
Three-dimensional space is not evolving, through time (fourth-dimensionally); rather all of space and time equally exist as a continuum, a physical structure that is fixed and complete. Reality is a fourth-dimensional spacetime continuum, and within this reality there is no true distinction between the past, the present and the future.
And yet, our lives are based upon the differences
between the past, the present and the future. We live in the present; it is the moment of our awareness, the time of decisions and spontaneous reactions, the time of being alive. The past, on the other hand, is over, complete, unchanging, fixed for all eternity. And the future is unformed, malleable, dependent upon our choices and plans—in other words, our free will.
Free will is built into the distinctions between the past, the present and the future. And free will is an integral part of our identities, of who we are.
We seek, then, to restore our identities, our very sense of self, our free will, while observing and honoring our laws of physics.
Very soon after Einstein completed his special theory of relativity, in 1905, he almost immediately began searching for an even bigger, better theory, one which would include gravity. The result was his general theory of relativity, which he completed in 1915. (When we refer to “Einstein’s theory of relativity,” we are in fact referring to both theories, since the special theory is a special case of the general theory, but is still separate and important enough to retain an individual identity.)
But then, almost immediately after this accomplishment, Einstein—being Einstein—began searching for an even bigger, better theory, one which would include electromagnetism, as well. This search slowly broadened into a search for a general, all-inclusive theory that would explain all phenomena, one which might even do away with quantum mechanics, as it was currently formulated. He really
disliked the prevailing interpretation of quantum reality, which was basically no “reality” at all.
This search, unfortunately, never bore fruit, but the point is that Einstein, we are suggesting, may have been a little too eager to move on to greener pastures. As Einstein himself said, “I have thought a hundred times as much about the quantum problems as I have about general relativity theory.”
On the one hand, Einstein of course accepted his theory of relativity—how could he not? But on the other hand, he was willing to abandon this theory if he could devise a larger, more inclusive theory—how could he not?
We would like to suggest, perhaps blasphemously, that Einstein was never 100% committed to his own theory. Consider this: When Einstein first formulated his special theory of relativity, it was without any concept of the fourth-dimensional spacetime continuum in mind. It took Hermann Minkowski to come along and reformulate the special theory of relativity into a geometrical vision of spacetime, and Einstein at first totally rejected this interpretation, calling it “superfluous learnedness,” even joking that, once mathematicians had got a hold of his theory, he could no longer understand it.
Of course, he did come to understand it, and went on to use this interpretation while formulating his general theory of relativity. And, from the quote we began with, he obviously came to accept the consequences of living within a fourth-dimensional spacetime continuum—that is, a physical reality that has no true distinctions between the past, present and future.
But, perhaps, this explains why he did not pursue the concept of the fourth-dimensional spacetime continuum conceptually, exactly as it was
, to see if it held more gems about the reality we do live in, here and now.
He did, obviously, extensively explore the scientific
consequences of his theory—realizing, for example, soon after completing his general theory of relativity, that it could be applied to the entire universe. But as far as analyzing spacetime for truths about our normal, human, everyday lives—that there might, in other words, be personal truths and meanings hidden within this physical universe described by relativity—Einstein simply did not think that way.
This, however, is the path we will explore.
For us, personally, this means that our past moments still exist, within the fourth-dimensional spacetime continuum. Our growth within our mother’s womb, our birth, our childhood, our continuing development and maturation, still exist within the fabric of spacetime.
Our future, also, “already” exists, within the spacetime continuum. Our aging, our future experiences, our eventual death, all exist out there, within spacetime.
But these moments do not simply exist as separate entities, having no relationship to one another. Relativity describes spacetime as a continuum.
We exist continuously
through time, as a single, complete, holistic fourth-dimensional organism.
We are fourth-dimensional beings.
In three-dimensional space we might define our physical bodies as existing between, say, the bottom of our feet to the top of our heads. In fourth-dimensional spacetime we likewise define the physical existence of our fourth-dimensional beings as existing between, say, two distinct “events.” The first event we might define as the moment we were first conceived, as a single cell; the last event we define as the moment we die, and our awareness ceases. We exist between these two events as a physical, continuous
fourth-dimensional body—as a fourth-dimensional being.
We have now slightly passed beyond the point in which the ordinary human, both layman and scientist, stops thinking about these things.
Why? Why is this concept never elaborated upon in popular science books?
Is this concept simply too far beyond our everyday experience? Does it mark the boundary beyond which the mind struggles too hard to comprehend?
Perhaps, but consider paradigm shifts from the past, ones we have already successfully conquered. We learned the earth is not the center of the universe, that humans and apes evolved from the same ancestors, that winds and earthquakes have natural explanations, and are not the whimsy of the gods. Our concept of reality has steadily evolved and matured over the years, improving and clarifying our picture of the world we live in.
We believe it is premature to suggest the human mind has reached a limit of comprehension, a level beyond which we simply cannot pass.
Another possibility, then, is perhaps we simply need more time to digest this new reality. We need more than the hundred years that has already passed; perhaps we need several hundred years.
Although possible, we stubbornly persistent refuse to wait that long. So, we will focus on a third possibility, instead.
Perhaps there is simply a psychological barrier preventing us from seriously contemplating our existence as fourth-dimensional beings. After all, if our past, present and future exist, then free will must be an illusion. We cannot be making decisions in the present that will decide our future, because that future already exists. We are not really reacting spontaneously to situations, making meaningful plans or goals, weighing outcomes, making choices. All future moments exist, and we only think
we are making decisions, choices and plans.
We are forced to the conclusion that our fourth-dimensional beings are frozen, static and unchanging, along with the rest of the spacetime continuum. Our beings resemble fossils stuck in amber—the amber of spacetime. We cannot move, which within the fourth-dimensional spacetime continuum means we cannot change our destinies. We are trapped, unable to live freely.
And yet we are conscious; we are alive.
Who would want to live in such a world? How could
you live in such a world? What would be the basis of living, of thinking, of doing? How can we not
make decisions, have spontaneous reactions, have plans for next week, next year, or tonight?
The mind rebels. Let us stop thinking about such matters; let us turn our mind to other things.
This is the mental barrier causing most people (we will assume) to turn away, to look elsewhere. But we believe it is time we moved passed this barrier, to grab the bull by the horns and face our scientific world on its own terms, and ours.
the book, Now: The Physics of Time,
by Richard A. Muller.
The solution Muller offers is elegant in its simplicity, even astonishingly so. Upon hearing it the question that immediately springs to mind is, how could no one have thought of this before?
In his book, Muller does not mention fourth-dimensional beings. (We understand; no one else does, either.) In fact, even though he discusses the fourth-dimensional spacetime continuum, he never actually uses this phrase; the closest he comes is when he refers to “four-dimensional space-time” in passing, a few times. This is not a criticism; it simply shows how he thinks about the problem, which is a clue to the solution he comes up with.
Muller is primarily concerned with “the moment now,” and searches for a way to restore the meaning of this moment within the physical universe we live in—that is, within the laws of physics. This replicates our dilemma, the one we have outlined above. Although he does not elaborate on this issue, if you solve the problem of now
, so that the present moment has the meaning we humans have always given it (spontaneity, free will, etc.), then you automatically
restore meaning back to the concepts of the past and the future.
We have known for many years that the universe is expanding. Muller proposes that not only is space expanding, but that time is, as well.
There is not only more space, with the expansion of the universe, there is also more time. What we call now
is the leading edge of this expansion. The future does not yet exist.
We are free in this present moment to decide our fates, to make our decisions and plans.
He calls this universe “the 4-D Big Bang,” to emphasize the fact that both space and time
are still being created, right up to the moment now.
If nothing else, with the publication of his book, Richard Muller demonstrates that he is stubbornly persistent—he believes, despite the equations of physics, and of Einstein’s relativity, that our human perception of a flowing time is an accurate description of reality. Free will exists. But he is also a dedicated scientist who honors and respects the laws of physics. (In our book, we collectively refer to all such adventurers, scattered throughout spacetime, as The League of the Stubbornly Persistent.)
The genius of this simple idea is that it respects the spirit and equations of relativity. The basis of the special theory of relativity is the concept of simultaneous events—that the simultaneous events in my frame of reference will not be simultaneous events in your frame of reference. But in Muller’s theory, no matter whose frame of reference it is, their now
is at the edge of the expansion of time.
All of us only see into the past, anyway. Light takes a moment of time to reach our eyes, and the farther away an object is, the more we are seeing the object “in the past.” Our other senses take even longer to record the world around us. Everything we sense is in some degree in the past. We can define
our “present” by subtracting (intellectually, mathematically) how long it took light to reach our eyes, and extrapolate from there, but we can never actually sense
this “present” moment in the present
This is a somewhat removed way of describing the special theory of relativity. Everyone will define the present moment somewhat differently from everyone else, because of their unique location within the spacetime continuum.
In Muller’s theory, everyone’s now is at the leading moment of the creation of time, and our free will is flowing forward with the present moment.
Translating Muller’s theory into our own terminology, our fourth-dimensional beings are not yet “complete.” They are still coming into existence; they exist up to the moment now.
Our future selves have not yet formed. Our beings only exist completely when we die, and then
they become that fossil stuck in the amber of spacetime.
However, the closest Muller comes to discussing our existence as fourth-dimensional beings is in these few lines, when he asks the question,
“Why do you feel you exist in the present? Actually, you exist in the past too; you know that quite well. You exist backward in time right up to the moment you were born (or conceived, depending on your definition of life). Your focus on the present comes largely from the fact that, unlike the past, it is subject to your free will.”
Then, a few pages later, he says,
“We live in the past just as we live in the present, but we can’t change the past.”
In his book, Muller does not elaborate any further on these ideas.
In 1964, physicists Arno Penzias
and Robert Wilson
were working at Bell Labs in Holmdel, New Jersey, setting up ultra-sensitive microwave receivers for radio astronomy observations.
No matter what the two did, they couldn't rid the receivers of background radio noise that, puzzlingly, seemed to be coming from all directions at once. Penzias contacted Princeton University physicist Robert Dicke
who suggested that the radio noise might be cosmic microwave background radiation (CMB), which is primordial microwave radiation that fills the universe.
And that is the story of the discovery of CMB. Simple and elegant.
For their discovery, Penzias and Wilson received the 1978 Nobel Prize in Physics, and for good reason. Their work ushered us into a new age of cosmology, allowing scientists to study and understand our universe as never before.
According to the broadly accepted theory for the origin of our universe, for the first several hundred thousand years after the Big Bang, our universe was filled with a ferociously hot plasma comprised of nuclei, electrons, and photons, which scattered light.
By around 380,000 years of age, the continued expansion of our universe caused it to cool to below 3000 degrees K, which allowed electrons to combine with nuclei to form neutral atoms, and the absorption of free electrons allowed light to illuminate the dark.
Evidence of this, in the form of radiation from the cosmic microwave background (the previously mentioned CMB), is what was detected by Penzias and Wilson, and it helped establish the Big Bang theory of cosmology.
Over the eons, continued expansion cooled our universe to a temperature of just around 2.7 K, but that temperature isn't uniform. Differences in temperature arise from the fact that matter is not uniformly distributed throughout the universe. This is thought to be caused by tiny quantum density fluctuations that occurred right after the Big Bang.
The "Cold Spot" Source: WMAP/Wikimedia Commons
One spot, in particular, seen from the Southern Hemisphere in the constellation Eridanus, is particularly cold, around 0.00015 degrees colder than its surroundings. Dubbed the "Cold Spot", scientists originally thought it was a "supervoid," an area that contains far fewer galaxies than normal.
Then, in 2017, researchers at the UK's Durham University Centre for Extragalactic Astronomy published research they say suggests that the Cold Spot isn't a supervoid after all.
Instead? It may be evidence of alien universes.
Durham Professor Tom Shanks proposed
what he described as a "more exotic" explanation for the Cold Spot. In his work, Shanks argued that the Cold Spot was "caused by a collision between our universe and another bubble universe...The Cold Spot might be taken as the first evidence for the multiverse - and billions of other universes may exist like our own." Universes, perhaps with different laws of physics.
Previously, physicists including Anthony Aguirre, Matt Johnson, and Matt Kleban had pointed out
that a collision between our bubble universe and another bubble in the multiverse would, in fact, produce an imprint on the cosmic background radiation. Additionally, they noted that it would appear as a round spot having either a higher or a lower level of radiation intensity.
Shanks' proposal seems to fit the bill, but could this feature really be evidence of an infinite multitude of universes that exist beyond our own?
By way of concluding, hundreds of papers and books have been completed on your topics. I urge you to reach far beyond what I have briefly offered you because by doing so, you will begin to learn physics and to better refine your questions. For your best investigation of your three topics and their attendant questions, you need to explore and better understand yourself, the nature of your questions and deeply enjoy the study of physics. I began my interest at five years old with a book my mother gave me: The Universe and Dr. Einstein by Lincoln Barnett, © 1948, 1964, 2005. That was followed by The Golden Book of Stars by Herbert Zim and Robert Baker, ©1951. Since then I have continued my studies with many hundreds of books, but these two books are always nearby so I can see how far I've come.
Let me offer you some advice - "Never, ever, ever, ever give up." -- Winston S. Churchill
"The pursuit of science has often been compared to the scaling of mountains, high and not so high. But who amongst us can hope, even in imagination, to scale the Everest and reach its summit when the sky is blue and the air is still, and in the stillness of the air survey the entire Himalayan range in the dazzling white of the snow stretching to infinity? None of us can hope for a comparable vision of nature and of the universe around us. But there is nothing mean or lowly in standing in the valley below and awaiting the sun to rise over Kangchinjunga*.
" -- Subrahmanyan Chandresakar
"We are star stuff which has taken destiny into its hands." -- Carl Sagan
* Kangchinjunga, in Nepali Kumbhkaran Lungur, is the world's third highest mountain, with an elevation of 28,169 feet (8,586 metres). It is situated in the eastern Himalayas on the border between Sikkim state, northeastern India, and eastern Nepal, 46 miles (74 km) north-northwest of Darjiling, Sikkim. The mountain is part of the Great Himalayan Range.
The great Himalaya Mountain Range formed as a result of tectonic forces driving two continental plates towards each other, the Indian and Eurasian Plates.
The Himalaya Mountains are best known for their immense peaks, such as the towering Mt. Everest, which stands at 8,848 meters (29,029 feet) above sea level and is the highest mountain on Earth. Besides Mt. Everest, the Himalayas contain many other high peaks, making it the highest mountain range on Earth. Stretching over 2,900 km along the border between the Tibetan Plateau and India, the Himalayas are evidence of plate tectonics and what happens when two continents, the Indian and the Eurasian plate, collide.