There are two gravitational conditions. First is the common notion of Relativistic gravitation, which tells us that gravity is a result of the curvature of spacetime caused by the presence of mass. This form of gravity is most familiar to us. When we look up at the night sky, we are peering at the stars from deep within the earth’s Gravity Well, which also happens to be fairly deep within the Sun’s Gravity Well.
Kepler’s Laws of planetary motion, Einstein’s General Relativity, and even Newtonian Gravitation all provide good frameworks for understanding what we see in the skies, especially when it comes to the behavior of nearby celestial objects like the planets in our Solar System.
However, applying what we have learned about gravitation to our observations of other galaxies, especially spiral galaxies, we find that they do not
seem to behave as we expect. As we have discussed at length, there simply isn’t enough visible matter within them to account for their ability to hold their shapes as they rotate. We can also reasonably conclude that since this phenomena is at work in virtually every other galaxy we observe, the same conditions almost certainly apply to our own Milky Way Galaxy as well.
If we back up for a moment and recall our earlier discussions about Dark Energy and Universal Expansion, we know that the Universe is expanding at an ever-increasing rate; yet our galaxy, which is usually estimated to be around 13 billion years old, isn’t stretching. It appears to rotating happily along, just like the other spiral galaxies we see in the skies.
This means that the galaxies seem to be, somehow, exempt from Universal Expansion, except for the fact that they are drifting away from one another. Internally, they hold together quite well. How could that be? Does the presence of matter somehow cancel the effects of Dark Energy? My guess is that it does not. The presence of matter is certainly related, but as a symptom more than a cause. Here’s how.
In my post on Galaxy Formation and Spacetime Stress
, I briefly discussed the question of how substances and objects respond to stress. One of my analogies used water cavitation as an example of how something that is stable under one set of conditions, can break down when pressed beyond certain boundaries or tolerances. I concluded that post with a question: Is it possible that spacetime itself could be susceptible to the stresses of Universal Expansion?
I believe that it must be. Indeed, the enormous stresses of Universal Expansion likely manifests in at least two important ways. One relates to gravitation, and the other relates to the origins of matter.
First, I submit that under the tremendous stress of Universal Expansion, spacetime itself reacts. There may not be a good word with which to label this event. Perhaps we could say that spacetime tears, or collapses, or cavitates. I think that the closest match is cavitation
- that spacetime itself distorts and curves into non-flat regions. As we already know, Gravity Wells are said to be regions of curved spacetime. Under Universal Expansion, this curvature exhibits the effects of gravitation (it is non-flat), but without any mass to account for it. Sound familiar?
To briefly summarize this part of the equation, let us say that there are two fundamental sources of natural gravitation, as follows:
- Gravitation that results from the curvature of spacetime caused by the presence of mass (this generally occurs on smaller scales).
- Gravitation caused by the deformation of spacetime resulting from Universal Expansion (this generally occurs on larger scales).
This understanding of gravitation constitutes half of what I believe to be a high-level, but complete explanation for Dark Matter. Essentially, galaxies begin as regions of Spacetime Cavitation resulting from Universal Expansion, which often take on whirlpool-like shapes.
Since newly formed galaxies are a result of cavitation, their structures are maintained via the combination of Spacetime Cavitation Gravitation
and Mass Gravitation
, where, on smaller scales such as solar systems, gravitation is based on mass (spacetime curvature resulting from the presence of mass), but on the larger scales of galaxies, structure is maintained within the underlying, curved Spacetime fabric (spacetime curvature caused by cavitation). In other words, visible matter rests upon the non-flat, preexisting Spacetime structures resulting from cavitation, like bits of Styrofoam floating upon a whirlpool of water draining from a kitchen sink. This removes the apparent discrepancy between galaxy structure and the insufficient mass to account for it; and further removes the need for Dark Matter altogether (unless we redefine Dark Matter itself as merely a vacuum of Spacetime, which may be useful, but more on this later).
This means that galaxies could be more accurately thought of as regions of curved spacetime - enormous Gravity Wells - rather than as collections of matter (we will discuss how matter plays into this in the next post). The relatively even distribution of galaxies throughout the observable Universe is unlikely to be a quirk of the Big Bang. I submit that galaxies simply form where the spacetime fabric breaks down (cavitates) at points of extreme stress, most likely as a result of Universal Expansion, in a way very analogous to how gasses form in water when decompressed.
Interestingly, astronomers have discovered an object in space that directly supports this hypotheses, which was written about in a BBC News article in February, 2005
. The article discusses a region of space that possesses the form and structure of a rotating galaxy, but without stars. Instead, the region is filled with hydrogen - a hydrogen disc. I will discuss the importance of this discovery, and its particular relevance to Dark Matter in the next post.
A quick note: The star-less galaxy above was discovered several years after I formed the Dark Matter hypotheses discussed in this blog series. When I happened across the article, which discusses the presence of an unmistakable galactic structure containing virtually nothing except hydrogen, it aligned so perfectly with my hypotheses that I was astounded. I had prior, no expectation or hope that such direct and supporting evidence would surface in my lifetime. As we will discuss in the next post, the presence of hydrogen in this star-less galaxy is key and critical to the completion of the Dark Matter question.