Theory and planets: what is right?

In general, I reserve this blog to support my science fiction writing, but since I try to put some real science in my writing, I thought just once I would venture into the slightly more scientific. As mentioned in previous posts, I have a completely different view of how planets, so the question is, why? Surely everyone else cannot be wrong? The answer to that depends on whether everyone goes back to first principles and satisfies themselves, and how many lazily accept what is put in front of them. That does not mean that it is wrong, however. Just because people are lazy merely makes them irrelevant. After all, what is wrong with the standard theory?

My answer to that is, in the standard theory, computations start with a uniform distribution of planetesimals formed in the disk of gas from which the star forms. From then on, gravity requires the planetesimals to collide, and it is assumed that from these collisions, planets form. I believe there are two things wrong with that picture. The first is, there is no known mechanism to get to planetesimals. The second is that while gravity may be the mechanism by which planets complete their growth, it is not the mechanism by which it starts. The reader may immediately protest and say that even if we have no idea how planetesimals form, something had to start small and accrete, otherwise there would be no planets. That is true, but just because something had to start small does not mean there is a uniform distribution throughout the accretion disk.

My theory is that it is chemistry that causes everything to start, and different chemistries occur at different temperatures. This leads to the different planets having different properties and somewhat different compositions.

The questions then are: am I right? does it matter? To the first, if I am wrong it should be possible to falsify it. So far, nobody has, so my theory is still alive. Whether it matters depends on whether you believe in science or fairy stories. If you believe that any story will do as long as you like it, well, that is certainly not science, at least in the sense that I signed up to in my youth.

So, if I am correct, what is the probability of finding suitable planets for life? Accretion disks last between 1 to even as much as 30 My. The longer the disk lasts, the longer planets pick up material, which means the bigger they are. For me, an important observation was the detection of a planet of about six times Jupiter’s mass that was about three times further from its star (with the name LkCa 15) than Jupiter. The star is approximately 2 My old. Now, the further from the star, the less dense the material, and this star is slightly smaller than our sun. The original computations required about 15 My or more to get Jupiter around our star, so they cannot be quite correct, although that is irrelevant to this question. No matter what the mechanism of accretion, Jupiter had to start accreting faster than this planet because the density of starting material must be seriously greater, which means that we can only get our solar system if the disk was cleared out very much sooner than 2 My. People ask, is there anything special regarding our solar system? I believe this very rapid cleanout of the disk will eliminate the great bulk of the planetary systems. Does it matter if they get bigger? Unfortunately, yes, because the bigger the planets get, the bigger the gravitational interactions between them, so the more likely they are to interact. If they do, orbits become chaotic, and planets can be eliminated from the system as other orbits become highly elliptical.

If anyone is interested in this theory, Planetary Formation and Biogenesis (http://www.amazon.com/dp/B007T0QE6I )

will be available for 99 cents  as a special promo on Amazon.com (and 99p on Amazon.co.uk) on Friday 13, and it will gradually increase in price over the next few days. Similarly priced on Friday 13 is my novel Red Gold, (http://www.amazon.com/dp/B009U0458Y  ) which is about fraud during the settlement of Mars, and as noted in my previous post, is one of the very few examples of a novel in which a genuine theory got started.

Another Wellington storm

Yet another storm hit Wellington; this time winds were a mere maximum of 165 k/h (about 100 mph). Is this climate change? Whatever, it is interesting that climate change is now a major concern, which raises the question, what can we do about it? Suppose we answer, “Stop burning fossil fuels,” what would the effect be? Currently, the atmospheric concentration of carbon dioxide is about 400 parts per million (compared with about 280 ppm at the beginning of the Industrial Revolution). If we are concerned about the effects of such atmospheric carbon dioxide, then if we stop producing it right now, the 400 ppm remain. Now, as noted in the last post, the climate shows strong signs of what physicists call hysteresis. This is when the effect is something depends on how you got there, where the system has “memory” of previous times. In this aspect, the Greenland ice sheets are actually the last remnants of the last great Ice Age. As we heat the planet, all that happens first in some places is that ice melts, the extra heat being absorbed by the melting ice without any temperature increase. In other words, for a while what you see is not what you are going to get!

In my opinion, the major problem civilization is going to face is rising sea levels. If the Greenland Ice Sheet melts, then the sea will rise about 7 meters. Take a look at Google Earth and see what goes. Amongst other places, a significant fraction of Bangla Desh, and essentially all Pacific islands based on coral reefs (as opposed to the volcanic basalt peaks, but you cannot live on the side of them). So, how do you defend against that?

 One suggestion is to build sea walls. These would have to be around all the land, including alongside riverbanks, and they may have to last tens of thousands of years. And, of course, while you are making all the required concrete and moving rock, you are probably generating massive amounts of further carbon dioxide, which will lead to more of the Antarctic ice melting, thus cancelling any value from your efforts. You could build walls of up to fifty meters high, and that would certainly be adequate for as long as the walls last.

 You could try removing the carbon dioxide from the environment. At first sight this seems futile; there is just too much there. However, at least some can be removed without much effort if we regrow forests. You would have to start planting them, but once underway, they would happily consume carbon. Even more spectacular would be to grow marine algae. The kelps such as Macrocystis pyrifera are extremely fast growing, and you can harvest them by mowing them. I rather fancy collecting such kelp and using it to make either biofuel or other chemicals. The key is to ensure that the carbon is removed from the ocean.

 Currently, we produce about 10 billion tonne per annum of carbon dioxide. That means we have to remove 10 billion tonne per annum just to break even. It is unlikely we can do that, although what we can do, we should, so what other options are there? A massive deployment of nuclear power would slow the fossil fuel burning, but it would not remove any of the current 400 ppm, and who wants nuclear power?

 The simplest answer is for every tonne of water melted by the ocean currents, we deposit a tonne of snow into the ice sheets. That involves geoengineering, and the problem is, when you interfere like that with nature, the effects are probably not that readily calculated. Such proposals in the past have been met with opposition. The problem is, some countries are going to be adversely affected by the geoengineering, and these are the ones that, in the first place caused the problem. Of course if we do nothing, it is the Pacific Islanders and the Bangla Deshis who pay. Do we know what will happen if we intervene? No, we do not, but we know what will happen if we do not. Of course there is another problem: how do we decide, and who decides?