11.) Why Study Gravity?

Why do I, a simple beast of burden, want to study gravity? I am, if nothing else, a curious donkey. Gravitation seems to cause what would otherwise be randomly dispersed matter to coalesce and form into everything we see and know ... it's right at the heart of it all. It's the glue that holds everything together. It affects and governs how everything moves. It's vital to the process of nuclear fusion that powers the sun and the stars. Though this elemental, underlying and invisible force is at the very core of what we perceive as our physical reality, we do not completely understand it.

Aristotle and others introduced us to the concept of gravity. Galileo, Newton and many others brought us to a much higher level of understanding. More recently, Einstein and countless others have brought our comprehension to an even higher level, but there's a problem.

• A Problem: Einstein's theories have held up very well for many years. Many of the behaviors of the universe, (at least those which we are currently able to observe), appear to support his theories. The problem lies in what many believe may be limits to Einstein's theories called "singularities".

• Gravitational Singularity: "A point in spacetime in which gravitational forces cause matter to have an infinite density and zero volume." (Wikipedia, "Gravitational singularity", http://en.wikipedia.org/wiki/Gravitational_singularity)
  

This concept applies to widely held theories that are predicted by Einstein's Theory of general relativity; cosmological theories like the "Big Bang" and astrophysical theories about "Black Holes". I have heard it stated that these singularities are said to be places and times where "the laws of physics break down or don't apply".

"Many theories in physics have mathematical singularities of one kind or another. Equations for these physical theories predict that the rate of change of some quantity becomes infinite or increases without limit. This is generally a sign of a missing piece in the theory." (Wikipedia, "Gravitational singularity", http://en.wikipedia.org/wiki/Gravitational_singularity)

Now you're talking like a donkey. Perhaps Einstein's work was not done.

• Another Problem: Currently accepted theories of quantum mechanics and general relativity are difficult to combine.

"Even with the defining postulates of both Einstein's theory of general relativity and quantum theory being indisputably supported by rigorous and repeated empirical evidence and while they do not directly contradict each other theoretically, (at least with regard to primary claims), they are resistant to being incorporated within one cohesive model." In donkey language this means that our understanding is either incorrect, incomplete or both.

"Einstein himself is well known for rejecting some of the claims of quantum mechanics. While clearly contributing to the field, he did not accept the more philosophical consequences and interpretations of quantum mechanics."

"The lack of a correct theory of quantum gravity is an important issue in cosmology and physicists' search for an elegant "theory of everything". Thus, resolving the inconsistencies between both theories has been a major goal of twentieth- and twenty-first-century physics. Many prominent physicists, including Stephen Hawking, have labored in the attempt to discover a theory underlying everything, combining not only different models of subatomic physics, but also deriving the universe's four forces —the strong force, electromagnetism, weak force, and gravity— from a single force or phenomenon." (from Wikipedia "Quantum mechanics" at http://en.wikipedia.org/wiki/Quantum_mechanics#
Quantum_mechanics_and_classical_physics).

Before continuing, please allow me to clarify and emphasize an important point. I am a poor, humble and ignorant donkey. What I am about to propose reflects a completely unqualified opinion, to say the least. Think of it as like a fan trying to predict who will win a football game before it starts. It reflects my current, vastly undereducated view of the universe.

I doubt that I am correct about what follows and I am sure that, as I become more educated on the subject, my views will change. In fact I'll be disappointed if they don't. I am much more likely to be wrong than right. I am also not concerned that "making a guess" will influence what I learn. On the contrary, I will be looking to challenge and refute these ideas at every step along the way. Think of it as like having a Socratic dialogue with myself.

Please recall that my strengths include skepticism and open-mindedness, and realize that along with ignorance comes a certain amount of objectivity. I have not yet become indoctrinated in a particular theory or school of thought, which is why I think this exercise is valuable. It also gives me a reference point later, in the event that I need to remember exactly where I began.

• The Tidal Theory of the Universe: by Donkey Hoteee.
  

The universe is in a state of constant motion and change. Though the space the universe occupies is infinite, I believe there is a finite amount of matter and energy in our universe. After all, the space the universe occupies is nothing and you can have an infinite amount of nothing. There's more than enough to go around! But, I don't believe there is an infinite amount of something, (matter, energy, and ?), in the universe. Though there may be other universes, from this simple donkey's point of view, ours is finite and closed.

I also do not believe that the "laws of physics break down or don't apply", but only that our understanding of them does, because it is not complete and / or possibly not correct.

In my theory the universe is not "ever expanding", it is only currently expanding. To say that it is ever expanding is like watching the tide come in at the beach and believing that the ocean is "ever expanding".

I also don't believe that the universe is "ever accelerating", but instead that it is only currently accelerating. To say that it is ever accelerating is like watching a car accelerate as it goes by and believing that it is "ever accelerating". I am puzzled by theories about the universe being accelerated by "Dark Energy". Though cosmologists admit this is another way of saying, "we don't know yet", it sounds a lot like saying thunder is caused by Thor and his hammer to a simple donkey.

I believe a "Big Bang" took place. It did not begin with a "singularity". It was not THE "Big Bang", but A "Big Bang". It was one of many, (perhaps an infinite number), of the biggest hypernovae there can be in our universe. The universe wasn't created by the most recent "Big Bang", it was just rearranged.

Look at the life cycle of a star.

• A Star is Born.

1.) "New stars form from large, cold, (10 degrees Kelvin), clouds of dust and gas (mostly hydrogen).

2.) Gravity or other forces, (like the passage of a nearby star or the shock wave from an exploding supernova), cause "clumps to form inside the cloud.

3.) The clumps collapse inward drawing gas inward by gravity."

4.) The collapsing and compressed clumps form one larger clump, which heats up.

5.) "This hot and collapsing clump begins to rotate and flatten out into a disc.

6.) The disc continues to rotate faster, draw more gas and dust inward, and heat up," even more.

7.) "After about a million years or so, a small, hot, (1500 degrees Kelvin), dense core forms in the disc's center called a protostar.

8.) As gas and dust continue to fall inward in the disc, they give up energy to the protostar, which heats up more" and more.

9.) "When the temperature of the protostar reaches about 7 million degrees Kelvin, hydrogen begins to fuse to make helium and release energy", (nuclear fusion takes place).

10.) "Material continues to fall into the young star for millions of years because the collapse due to gravity is greater than the outward pressure exerted by nuclear fusion. Therefore, the protostar's internal temperature increases.

11.) If sufficient mass, (0.1 solar mass or greater), collapses into the protostar and the temperature gets hot enough for sustained fusion, then the protostar has a massive release of gas in the form of a jet called a bipolar flow. If the mass is not sufficient, the star will not form, but instead become a brown dwarf.

12.) The bipolar flow clears away gas and dust from the young star. Some of this gas and dust may later collect to form planets.

The young star is now stable. The outward pressure from hydrogen fusion balances the inward pull of gravity. The star enters what is called the main sequence." What happens next depends largely upon its mass.

• Life on the Main Sequence

"Stars on the main sequence burn by fusing hydrogen into helium. Large stars tend to have higher core temperatures than smaller stars. Therefore, large stars burn the hydrogen fuel in the core quickly, whereas, small stars burn it more slowly. The length of time that they spend on the main sequence depends upon how quickly the hydrogen gets used up. Therefore, massive stars have shorter lifetimes, (the Sun will burn for approximately 10 billion years). What happens once the hydrogen in the core is gone depends upon the mass of the star.

• The Death of a Star

Several billion years after its life starts, a star will die. How the star dies, however, depends on what type of star it is," or to be more specific, how massive it is.

Stars Like the Sun: When the core runs out of hydrogen fuel, it will contract under the weight of gravity. However, some hydrogen fusion will occur in the upper layers. As the core contracts, it heats up. This heats the upper layers, causing them to expand. As the outer layers expand, the radius of the star will increase and it will become a red giant."

"At some point after this, the core will become hot enough to cause the helium to fuse into carbon. When the helium fuel runs out, the core will expand and cool. The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula. Finally, the core will cool into a white dwarf and then eventually into a black dwarf. This entire process will take a few billion years.

Stars More Massive Than the Sun: When the core runs out of hydrogen, these stars fuse helium into carbon just like the Sun. However, after the helium is gone, their mass is enough to fuse carbon into heavier elements such as oxygen, neon, silicon, magnesium, sulfur and iron.

Once the core has turned to iron, it can burn no longer. The star collapses by its own gravity and the iron core heats up. The core becomes so tightly packed that protons and electrons merge to form neutrons. In less than a second, the iron core shrinks to a neutron core. The outer layers of the star fall inward on the neutron core, thereby crushing it further. The core heats to billions of degrees and explodes, (a supernova), thereby releasing large amounts of energy and material into space.

The shock wave from the supernova can initiate star formation in other interstellar clouds. The remains of the core can form a neutron star or a black hole depending upon the mass of the original star." (from "How Stars Work" from How Stuff Works at http://science.howstuffworks.com/star5.htm)

• Many Big Bangs - The Tidal Theory

At the center of my theory is the most massive proton star you can imagine. Actually it's probably more massive than any of us can imagine. I'll call it Alpha Infinity. Alpha Infinity, because of it's unimaginable mass, lives an dies very quickly, causing the hypernova to end all hypernovae, an enormous explosion, a really "Big Bang". Elements such as oxygen, neon, silicon, magnesium, sulfur and iron, (and many or perhaps most of the others on the Periodic Table), are scattered, creating our current known universe in its current form.

With nothing to obstruct or influence it but itself, our universe is expanding at an accelerated rate. But eventually, (we're talking a really, really long time here), all of matter's own gravity slows the expansion and the universe begins to contract, (cosmologists call this the "Big Crunch"), until it eventually forms the most massive proton star you can imagine, Alpha Infinity, which goes hypernova and ... well, you get the idea. A "Big Bang" happens over and over again.

"The Tide Rises, the Tide Falls" by Henry Wadsworth Longfellow

"The tide rises, the tide falls,
The twilight darkens, the curlew calls;
Along the sea-sands damp and brown
The traveller hastens toward the town,
And the tide rises, the tide falls.

Darkness settles on roofs and walls,
But the sea, the sea in the darkness calls;
The little waves, with their soft, white hands,
Efface the footprints in the sands,
And the tide rises, the tide falls.

The morning breaks; the steeds in their stalls
Stamp and neigh, as the hostler calls;
The day returns, but nevermore
Returns the traveller to the shore,
And the tide rises, the tide falls."

I have no idea what shape the universe takes, and will have to study a lot more chemistry, physics, astrophysics, mathematics and, of course, gravity to form an opinion. Red Shift phenomena, fluid dynamics, (specifically how they behave in a vacuum), and the study of time will also be critical to my understanding. Does a colossal super nova like that of Alpha Infinity radiate matter outwardly and equally in all directions to form a perfect sphere? Even if there is no other matter present to assert its gravitational influence, my guess is no.

With sincere and humble apologies to Edward Witten and many others, my simple donkey instincts also tell me that the universe, (like the world), is not flat! It's not a "membrane" or "parallel" to anything. It is three dimensional, (at least). There may be more dimensions, but my guess is that dimensions are actually just ideas that help us understand things. There is very little about the universe that is flat or linear, other than how we are taught to think about it. Also, I love rock and roll as much as anyone, but String Theory? Let's just say that I am open, but very skeptical.

• Please remember what theories are like ... even donkeys have one.

Talk is cheap. The hard part is doing the science. Galileo, Kepler and Newton didn't just theorize. They set out to prove their theories. They practiced science. They used scientific methods.

• I have begun to look up again.

I have begun to look up again with a purpose beyond just admiring the twinkly lights. Like Galileo, Kepler, Humboldt, Darwin and countless others I will study what I am able to observe. I will happily study our planet and the heavens beyond.

I'll study rivers, oceans, the atmosphere, (don't galaxies look a lot like hurricanes suspended in space?), and of course, the heavens. I'll study what others have learned and use that along with my observations to guess at what I am not able to observe directly. I will practice science. I will solve the riddle of gravitation.

I bought a poster today, a black and white portrait of Sir Isaac Newton. It displays a brief description of his accomplishments and a time line, (ironic, since I don't think time is linear). In fact I think that linear and two dimensional thinking and learning obfuscate our understanding of the universe in general, and time in particular.

What caught my attention and inspired me to purchase and display this poster was the quote at the top:

"If I have ever made any valuable discoveries, it has been owing more to patient attention than any other talent." Isaac Newton

Next blog entry: "Anecdotal, Pseudo-Scientific Psychobabble"