Thoughts

Well, today is a little crazy. I’m juggling various celebrations for my family this weekend, an upcoming trip to Canada on Sunday, school work, and … for some crazy reason, I’ve decided to make a blog post about geology.

I know geology may be somewhat random, but read on! Intriguing things (may) lay ahead.

I happen to have a little interest in geology. It stems from my general interest in Earth. I love and appreciate it, and at moments in my past, I’ve considered being a geologist. Geologists strive to understand the forces that shape this world around us, and to this day, many such forces remain a mystery. Exploring mysteries is what I’m all about.

Being a Geologist wannabe, I occasionally dwell on the specific forces that bring about this surprising place of beauty. In particular, I’m a little skeptical of “plate tectonics.” In case you’re unfamiliar, this is the notion that that Earth’s surface is a collection of various rigid ‘plates’ of crust which coast around on a soft, goo-like sub-crust called the “lithosphere.” As the plates drift in this geological gelatin, they interact with each other. One plate may slip under another plate, and when they do, we get mountainous Seattles and Californias (and breathtaking views, as I can now attest to). Elsewhere, plates pull apart, and we get deep, dark, mysterious mid-oceanic ridges. The physics of plate tectonics is fuzzily justifiable, so most accept it and move on with their lives. I decided to become a skeptic…

Assuming Earth’s size hasn’t changed much through the bulk of its history, the planet has essentially served as a liquid-covered host for some coasting continents that we, as humans, occupy. The “internal forces” that drive these plates just so happen to push the plates out of the liquid here and there, yielding these continents. Consider this; it’s obvious that the disparate continents of today were at one point connected. That’s why South America and Africa look like they ought to fit together like matching puzzle pieces. Today’s lands in fact stem from one giant connected super-continent called Rodinia, which, by initial assumptions, must have poked out of a vastly larger whole-planet-covering ocean. At some point, Rodinia split and began separating into various continents by way of internal forces, and today, we have our Earth.

They say “convection” is actually the agent driving these plates. This is the churning of non-solid material under the crust as heat enters and exits the system. Such heat can stem from the radioactively decaying elements below the lithosphere. It all works out by inspection, but we can’t inspect too deep yet, and to me, the convection argument is similar to arguing that humans operate because “food digests in their stomach, keeping their blood flowing.” It’s true, but talk about fudging on the details.

I guess tectonics theory has held its own against Geologists so far, but I’m more inclined to support the “expanding earth” theory. If you’re interested, have a look:

Wikipedia: Expanding Earth Theory

The gist of this theory is that the features of today’s crust have formed from internal growth of the earth, rather than convection, since the times of Rodinia. The theory says that the supercontinent was actually the entire surface of the planet. The ocean was either very small or non-existent.

The “Status” section of the above wikipedia page (as of Sept 25th, 2007) says that the theory was dismissed due to a lack of an explanation for the process that allows such a growth. Some, such as the comic book artist Neil Adams, have taken up this theory, and he in particular has taken a somewhat radical and confrontational stance on it. I feel such an approach serves to hurt an otherwise intriguing theory. The reason for my blog post today is to make public my idea on a possible cause for this growth that stays true to physical constraints.
I’m hoping this will get caught by a search spider and prompt investigation by future searchers in the geo-know.

An aside about science: Science is still a growing practice. I feel that any and all proposed theories ought to be analytically investigated to some extent. The slightest bit of evidence in favor of a theory should justify its exploration. Scientists should mainly propose, prove, and disprove. In the case of this theory, i get the impression that many simply dismissed the theory. They ought to keep their consideration open to new things, and only end their consideration once a proof of contradiction is given. If such a proof can’t be provided, the exploration for further evidence ought to continue until enough is found to reason over.

Of course, there are plenty of arguments contrary to this. I can guess at a few: “Certain things can never be proven, so the question will linger forever, bogging down resources/time/(grant)money. People and research groups can only tackle so much at any given time. Other matters are more pressing. Scientists have to eat. Etc.” All these arguments are true. To get around them, I say, let computers do the work. Use deductive databases! Problem solved Granted there are still a few open problems to be solved in the realm of automatic deduction in the presence of mis-information, unknowns, contradictions, and self-reference, but in time, science can (and should) benefit significantly from an automatic reasoning framework.

Anyway, back to Earth. Wikipedia tells me that they want a process that can cause Earth’s expansion. I think I have one, and I managed to convince myself with it so much that I decided to e-mail geologists at Stony Brook University to ask their opinions on it. I was curious if my theory holds up against the constraints of physics and the measurements we’ve taken of the Earth so far. I’m largely out of touch with the state of geology, so it’s best that I let the professionals consider the low-level details. One professor got back to me and said that no evidence existed to support planetary growth, though he suggested I pursue a career in geology ( which I appreciate! ). The other professor never replied =(

I want to post my theory here, just to have it out there in case it’s actually true. Here is the letter I sent.

If you read it, let me know if you think it’s plausible. In brief, the theory holds that Oxygen phase changes (coupled with associated volume expansion over time) can cause the slow expansion of the planet. I haven’t worked out all the details, but if you’re interested, pick it up and run with it. Try not to ‘dismiss’ it unless you know a reason it wouldn’t work, and in that case, let me know so I can change and/or drop my theory =) Also, if you decide to take it up, drop me a line. I’d be interested to see if anyone else out there would consider this.

Here is my original e-mail, and clips from the Professor’s response. I’ll only present the knowledge.

Hi Professor *****,

[...]

Back in my Geo classes, I remember the discussions of plate tectonics. However, not long ago I came across a talk on an alternate theory of continental formation called “Expanding Earth Theory”. The theory claims it’s possible that the Earth is actually growing, expanding outward due to some internal growth, and that this growth is the true cause of the continental separation from Rodinia. I also read that this theory was largely dismissed because the supporters could offer no solution for why this expansion might occur.

My first question is, is there any direct disproof of the expanding earth theory? Is there any particular geologic event that directly contradicts the possibility?

If it isn’t totally ruled out, I was wondering if it might be plausible that such a volume expansion might be caused by a phase transition of dense materials near the core into less dense material (with greater volume), triggered by the gradually decreasing pressure from the core outward. Specifically, I’m wondering if it’s possible that this is occurring with oxygen. I know that oxygen is a main component in most of the suspected minerals of the inner earth (not to mention outer), and I’ve also recently read some research that’s revealed that it has a dense red crystal phase at 10 MPa and also a liquid metallic phase near 100MPa. Is it possible that there is a large reservoir of metallic oxygen near the core that is slowly transitioning and expanding into red crystal oxygen, then farther into the forms that we’re familiar with in the upper crust and atmosphere? If so, is it possible that this phase transition might be generating heat that is ultimately being released in various surface features on the globe? [Could such a mechanism] serve as a cause of the ‘expansion’ in the expanding earth theory?

[...]

Summing it up, I think that a slow and gradual phase-change - from a very compressed, metal-like oxygen near the core, through a rich spectrum of phases (dense molecules at the core, to crystals at middle-earth pressure, to the larger spacious molecules we find in the upper atmosphere) - and an associated volume expansion can create the inner “push” for the expanse.

By analogy, think about how dry ice evaporates. The volume of the dry ice is initially very compact, locked in the crystal structure of the ice. As it slowly evaporates, the volume of molecules grows until they flow freely, filling their container. This is only a single phase change from solid to gas. This one change also takes quite a bit of time as temperature slowly breaks down the crystal structure of the ice.

Oxygen, from the core outward, can very well start as a metal-like substance at extreme pressure (100MPa, or the pressure at the core), then at some point switch to a red crystal substance (10MPa), then to a liquid, then to gas. These phases of oxygen have been created in lab conditions. Even more phases actually exist mid-way through the process, and after each change, volume increases. The fact that oxygen has metallic properties at core-earth pressure may even make it a candidate for the ‘metal’ that generates Earth’s magnetic field, though I don’t want to make too many off-the-cuff claims. The accepted belief is that the outer core is a mix of mostly iron, but in light of these interesting material properties at high pressures, new possibilities ought to be considered and old theories ought to be revisited as well.

Here are some clips from the response:

Earth is ever changing
…
Supposed that there is no addition to the mass, there are two ways
that a material could change its volume - change its temperature or
experience a phase change (from one crystal structure to another,
for example from ice to water). The temperature of the Earth’s
interior is controlled by three factors: radioactive heating by U, Th
and K elements, secular cooling and movement of materials from
one place to another (convection). Overall, convection does not
change much of the bulk budget of heat (since it just moves materials
around); and the secular cooling overwhelms the radioactive heating.
So the bulk Earth cools over time (and shrinks in volume). The major
phase changes occur in about the depths of 40 km, 410 km, 660 km
and of the Earth’s inner core. These phase changes change
the bulk volume of the Earth’s and phase changes strongly
depend on temperature, composition and pressure. There are
some phase changes related to the convection system that could
change the volume of the material, for example, the subducted slab;
but that change of volume is probably balanced by that of the returning
hot materials in the convection system. There are places that Earth is
expanding in response to the convection flow, but overall, there is
no evidence that the BULK Earth is expanding.

Are there any addition materials into the mantle? It depends on the
interactions of the Earth’s surface with the atmosphere. Overall,
the change of mass is probably balanced between the
atmosphere and Earth’s surface. The early Earth however
experienced degassing during the accretion stage.

Interesting! I should probably get back to him. I should also look for evidence confirming a bulk-earth expansion. I think I remember reading some recent research about this… lets see…

http://archives.cnn.com/2002/TECH/space/08/01/earth.pumpkin/index.html

Maybe? I need better references. Well, I’ve got to run. Thanks for reading. In the end, I like computers and I like geology… *shrug.* You have to like something!

If you’re curious about the properties of oxygen at high pressure that I mentioned above, see here for starter details:

“High-pressure oxygen: a non-conventional magnet studied by means of neutron diffraction”

-Rojo