Category Archives: science

the shape of a galaxy and its black hole

I was reading this article: Stirred, Not Shaken. Black Hole Antics Puff Up Whopper of a Galaxy.

Articles like this make me wonder whether the shape of a galaxy reflects the influences (gravity, spin, active/inactive) of the central black hole or lack thereof. Maybe a black hole with a mass and spin (moment of inertia) above a certain threshold causes a galaxy to become more spiral. Maybe if it spins with a wobble, the spiral develops a central bar. Maybe if the black hole has a moment of inertia that is below a certain threshold in proportion to the rest if the galaxy’s mass, the galaxy becomes elliptical.

Thoughts return to the weird relationship between the surface area of the black hole’s event horizon (not an existent, since “it” has no energy) to its entropy. Since entropy is a measure of information, the black hole behaves like a hologram. It again leads one to wonder whether the shape of the galaxy is a reflection of the information that is contained in the black hole.

quantum gravity unsolved

Modern physics is fundamentally broken. Quantum theory explains how the universe works at small scales, such as atoms. Quantum theory is remarkably accurate with an incredibly good agreement with experiments. The theory of general relativity explains how the universe works at large scales, such as stars and galaxies. General relativity is remarkably accurate with an incredibly good agreement with experiments. However, the two theories disagree with each other. Both theories are mostly correct, but also wrong in some ways. After decades of trying to reconcile the two theories of the universe, physicists are not close to formulating a theory of everything. There are several promising avenues of research, such as string theory and loop quantum gravity, but none of these has so far been successful.

It makes me wonder about where the error in thinking could be to have misled physicists throughout the world onto roads that are probably dead ends.

It’s been pretty obvious to many where the flaw in quantum theory lies. It treats the time dimension as being independent from the three space dimensions, and this is in complete contradiction to general relativity, which states that space and time form a single manifold. Quantum theory treats space and time as an absolute background, as if they exist independently from the particles and fields that make up reality. However, only particles and fields are real. Space and time as a background do not actually exist; they are mathematical constructs reflecting the geometry of some physical theory.

However, where is general relativity flawed? This is not as obvious. The most obvious conflict with quantum theory has always been gravity, which general relativity claims is the curvature of space-time. Quantum theory has never had a good explanation of gravity. The source of gravity is mass-energy.

Something else we should be aware of is the Standard Model of particle physics. It too represents our current best understanding of the universe. It too is flawed. It does not include gravity among other phenomena. And interestingly enough it predicts a particle called the Higgs boson, which is responsible for mass. However, the Higgs boson has never been experimentally observed. The Large Hadron Collider (LHC) is supposed to confirm or refute the existence of the Higgs boson, when it becomes operational.

Maybe this is more than just a coincidence that the Standard Model, which does not include gravity also predicts the origin of mass, which has eluded observation. Given that gravity is where the conflict lies between quantum theory and general relativity, perhaps we should take a closer look at mass-energy.

Let’s take a look at the Schrödinger equation from quantum theory:

The H is the Hamiltonian, which is the total energy of the system (potential + kinetic). The kinetic energy is proportional to mass. General relativity tells us that mass is equivalent to a whole lot of potential energy:E = mc2.

Meanwhile, special relativity tells us that mass is relative. The mass of something depends on how fast it is moving relative to the observer. The observer and the relative motion are other things that the Schrödinger equation does not account for.

We keep encountering mass in these equations. Maybe we don’t understand mass as well as we think we do. Which leads us to a misunderstanding of gravity, and consequently the geometry of space-time. I wonder if all of this points to mass as being the culprit, where we have been getting it all wrong. Mass is where I suspect the problem to be. If the LHC does not find the Higgs boson, I think this will tell us just how wrong we are about mass.

universe of events – cosmology in software

On my second reading of Three Roads to Quantum Gravity by Lee Smolin, the concept of a relational universe stands out as something fundamentally important.

Each measurement is supposed to reveal the state of the particle, frozen at some moment of time. A series of measurements is like a series of movie stills — they are all frozen moments.

The idea of a state in Newtonian physics shares with classical sculpture and painting the illusion of the frozen moment. This gives rise to the illusion that the world is composed of objects. (p.53)

In object oriented programming, the objects correspond to the particles. The focus is on capturing the state of the object, frozen at some moment of time. As methods are called on the object, changes to its state (variables) are like a series of movie stills.

Lee Smolin goes on to write:

If this were really the way the world is, then the primary description of something would be how it is, and change in it would be secondary. Change would be nothing but alterations in how something is. But relativity and quantum theory each tell us that this is not how the world is. They tell us — no, better they scream at us — that our world is a history of processes. Motion and change are primary. Nothing is, except in a very approximate and temporary sense. How something is, or what its state is, is an illusion. It may be a useful illusion for some purposes, but if we want to think fundamentally we must not lose sight of the essential fact that ‘is’ is an illusion. So to speak the language of the new physics we must learn a vocabulary in which process is more important than, and prior to, stasis. Actually, there is already available a suitable and very simple language which you will have no trouble understanding.

From this new point of view, the universe consists of a large number of events. An event may be thought of as the smallest part of a process, a smallest unit of change. But do not think of an event happening to an otherwise static object. It is just a change, no more than that.

The universe of events is a relational universe. That is, all its properties are described in terms of relationships between the events. The most important relationship that two events can have is causality. This is the same notion of causality that we found was essential to make sense of stories.

If objects are merely an illusion, and it is really causal events that are fundamental to modeling a universe that is relational and dynamical, then perhaps we should re-examine how effective object oriented programming is at producing software that effectively models real world processes. Classes of objects definitely focus on the static structure of the universe. The methods on these classes can be considered to correspond to events, which carry information in, perform some computation, and carry information out. However, the causal relationships between events is buried in the procedural code within each method; they are not expressed in a first class manner.

Personal productivity applications like spreadsheets and word processors model objects (e.g., documents) and relationships that undergo relatively simple processes involving only a few actors. The causal history of events is not as important, because there is only one set of objects in a document to maintain integrity among and the series of frozen moments model of the universe works rather well. Enterprise applications such as Enterprise Resource Planning (ERP) facilitate a multitude of parallel business processes that involve many actors and sophisticated collaborations. Each actor is performing transactions against some subset of objects, which are each progressing through a distinct life cycle. Maintaining integrity among the objects changed by these many concurrent events is incredibly complicated. It becomes important to keep a causal history of events in addition to the current state of the universe, as well as having a schedule of future events (for planning) that have not come to pass. A series of frozen moments becomes less appealing, whereas a set of processes and events seems like a better description of the universe.

cosmological constant

The energy density of empty space is called the cosmological constant. It accounts for the force that causes the expansion of the universe. Its value is approximately 10^-29 g/cm^3. This is an incredibly tiny positive number. They call this stuff dark energy.

As the universe expands, the density of ordinary matter like stars and rocks decreases because new matter is not magically appearing to fill in the space. The incredible thing about the cosmological constant is that the energy density of vacuum does not decrease as the universe expands with time. If this does not surprise you, then let me explore this a little deeper.

mass = density * volume

If the universe is expanding, then the volume is growing larger with time. If the density remains constant, then this would mean that the mass-energy of the universe is ever increasing.

Reconcile that with the First Law of Thermodynamics.

In any process, the total energy of the universe remains the same.

Are we to believe that the universe itself violates the First Law of Thermodynamics?

expanding universe

(follow-up to 2003/07/27)

Scientists observe the following phenomena:

  1. Based on observations of supernovae, galaxies are known to be moving farther away from each other in the universe.
  2. The farther away the galaxy is from us, the greater the red shift in the light from that galaxy. Similar to the Doppler effect, the faster the galaxy is moving away from us, the greater the wavelengths of light are shifted towards the red side of the electromagnetic spectrum. This means that the farther away the galaxy is from us, the faster it is moving away from us.
  3. The farther away the galaxy is from us, the more time it takes for light to travel, before it arrives for us to observe. Therefore, the greater the distance travelled, the farther back into history we are observing.

Based on these observations, scientists theorize that the universe has been expanding. Extrapolating back in time, the theory projects that in the distant past (13.7 billion years ago +/- 200 million years), the universe must have been very compact and incredibly hot and dense. This is the Big Bang theory.

They also conclude that the expansion of the universe has been accelerating.

I don’t understand how they can arrive at that conclusion.

If at greater distances, we observe greater red shift, this means that farther back in time we observe higher velocity of expansion. In other words, as time moves forward, the velocity of expansion decreases. Wouldn’t elementary physics tell us that the expansion of the universe is actually decelerating – NOT increasing in velocity?

red shift in an expanding universe

As we look into the distance, we see deep into the past towards the big bang. It is mind boggling how unintuitive this is. If you look far enough into the distance, you should be able to see the earliest moments of the universe. This is the cosmic background radiation. Quarks condensed into the first protons and neutrons.

What is more confusing to me is the interpretation of the evidence that suggests the universe is expanding at an increasing rate. This conclusion is based on observing red shifts. The farther an object is from us, the faster it appears to be moving away. Unless I’m misunderstanding something, doesn’t this tell us that the expansion of the universe is actually slowing down? Let me explain.

Wouldn’t an accelerating expansion demonstrate higher differences in velocity (red shift) for objects nearer to us? Since they are near, we see them as they were relatively recently as compared to far away objects. If the rate of expansion is accelerating, then observations of more recent events should show higher velocities than observations of events in the more distant past. On the other hand, if the velocity of distant objects is higher than the velocity of nearer objects, then shouldn’t it be logical to conclude that expansion is slowing rather than quickening?

quintessence – dark energy

I have begun to read Quintessence. It starts out rather dull. I am hoping that it picks up soon. Unlike End of Time, the author’s style is not provocative; he seems very methodical — though I’m only at the beginning, which contains all the introductory context.

Dark matter and dark energy have become a favorite topic for my curiosity. What better subject can there be to help stimulate the imagination? Observations suggest that there is something incredibly important throughout the universe that dominates its behavior, and no one knows what it is. These things cannot be sensed directly. They are completely different than anything we know today.

Free your mind.

Many people are unable to free their minds of what they know to be true, so that they can evaluate ideas from a different perspective. It is debilitating to be a rigid thinker. They are weak at evaluating alternative mental models, because they cannot apply their limited imagination in constructing such models.

What kind of image does the expanding universe invoke? Does your mind picture the universe itself as a ball growing larger, its boundaries stretching outwards? Or does it picture, as an observer within the universe itself, all of the galaxies moving away from eachother? Or does it picture a static universe without any notion of time or motion, and the expansion is merely a path in configuration space? Does it recognize the false notion of being an outside observer, while allowing this fiction to be imagined?

How do you picture the void of empty space? Is it a three (or higher) dimensional grid? Is it curved by the massive objects? Is it absolutely nothing at all, except for the void between things that actually exist? Or is it ethereal, filled with virtual particles that flash in and out of existence beyond our ability to perceive?

At many points in history, fundamental questions as simple as “what is space?” and “what is time?” have been asked and answered. Still we do not know the true answers; we only have intuitive notions based on teachings that have been socialized. We go through school learning mostly by rote the laws of the universe, such as those related to motion, momentum, and energy — notions that depend on understanding space and time. We are taught to treat space and time as intuitively obvious, because they are understood ostensibly. Yet, there may not be a single human being that has ever truly understood the nature of space and time — if those ideas have any correspondence to reality at all, and the jury is definitely out on that one. Despite this dilemma, the vast majority of students finish school with confidence that they know a great deal about space, time, motion, and many other important things. They don’t have an appreciation for the context of their knowledge — the limited scope of understanding that is encapsulated. They are taught the current state of understanding, which is good enough for most practical purposes in ordinary life. They are lies, or reasonable facsimiles of the truth, good enough to get you through most days without going too awry.

Just as the earth is not flat (though from a person’s viewpoint, it may appear that way), and the sun does not orbit the earth (though from a person’s viewpoint, it may appear that way), these ideas were once at the pinnacle of human knowledge, only to be invalidated later. We accept theories like general relativity and quantum mechanics because there isn’t yet any better explanation. They can be applied to good effect as a practical matter for a limited set of problems. But let us not forget that the accuracy of current theories has much room for improvement.

timeless – thinking outside the box

I am sitting here in a Boeing 737 on the tarmac, as maintenance personnel check over the aircraft to determine why some indicator lights are showing a problem. What has been occupying my mind is the first few pages I’ve read of The End of Time – The Next Revolution in Physics by Julian Barbour. This book is a great example of thinking outside the box.

Barbour suggests that there is in reality no such thing as time. It is merely a figment of our misinterpretation of the facts, which result from the limited scope of our personal experiences. This idea is very provocative, because it goes against intuition and it seemingly contradicts everything we know to be true. There is something extremely violent and destructive in this notion. Just the possibility of setting fire to something that we hold as fundamental is exciting.

This is very serendipitous. My life’s work seems to revolve around creative thinking. One of my fundamental responsibilities is to think outside the box to solve problems that are beyond the normal capacity of others. I must imagine what lies outside of common knowledge, and embrace possibilities that may be seemingly absurd or false, in order to discover that something out there is in fact precisely what must be true (or brought into reality). Thinking outside the box requires that in fact there is no box. Or perhaps that all those poor souls, who thought they were in the box, were actually floating outside a bubble. Or something much more bizarre.