Ross 128b a Habitable Planet?

Recently the news has been full of excitement that there may be a habitable planet around the red dwarf Ross 128. What we know about the star is that it has a mass of about 0.168 that of the sun, it has a surface temperature of about 3200 degrees K, it is about 9.4 billion years old (about twice as old as the sun) and consequently it is very short of heavy elements, because there had not been enough supernovae that long ago. The planet is about 1.38 the mass of Earth, and it is about 0.05 times as far from its star as Earth is. It also orbits its star every 9.9 days, so Christmas and birthdays would be a continual problem. Because it is so close to the star it gets almost 40% more irradiation than Earth does, so it is classified as being in the inner part of the so-called habitable zone. However, the “light” is mainly at the red end of the spectrum, and in the infrared. Even more bizarrely, in May this year the radio telescope at Arecibo appeared to pick up a radio signal from the star. Aliens? Er, not so fast. Everybody now seems to believe that the signal came from a geostationary satellite. Apparently here is yet another source of electromagnetic pollution. So could it have life?

The first question is, what sort of a planet is it? A lot of commentators have said that since it is about the size of Earth it will be a rocky planet. I don’t think so. In my ebook “Planetary Formation and Biogenesis” I argued that the composition of a planet depends on the temperature at which the object formed, because various things only stick together in a narrow temperature range, but there are many such zones, each giving planets of different composition. I gave a formula that very roughly argues at what distance from the star a given type of body starts forming, and if that is applied here, the planet would be a Saturn core. However, the formula was very approximate and made a number of assumptions, such as the gas all started at a uniform low temperature, and the loss of temperature as it migrated inwards was the same for every star. That is known to be wrong, but equally, we don’t know what causes the known variations, and once the star is formed, there is no way of knowing what happened so that was something that had to be ignored. What I did was to take the average of observed temperature distributions.

Another problem was that I modelled the centre of the accretion as a point. The size of the star is probably not that important for a G type star like the sun, but it will be very important for a red dwarf where everything happens so close to it. The forming star gives off radiation well before the thermonuclear reactions start through the heat of matter falling into it, and that radiation may move the snow point out. I discounted that largely because at the key time there would be a lot of dust between the planet and the star that would screen out most of the central heat, hence any effect from the star would be small. That is more questionable for a red dwarf. On the other hand, in the recently discovered TRAPPIST system, we have an estimate of the masses of the bodies, and a measurement of their size, and they have to have either a good water/ice content or they are very porous. So the planet could be a Jupiter core.

However, I think it is most unlikely to be a rocky planet because even apart from my mechanism, the rocky planets need silicates and iron to form (and other heavier elements) and Ross 128 is a very heavy metal deficient star, and it formed from a small gas cloud. It is hard to see how there would be enough material to form such a large planet from rocks. However, carbon, oxygen and nitrogen are the easiest elements to form, and are by far the most common elements other than hydrogen and helium. So in my theory, the most likely nature of Ross 128b is a very much larger and warmer version of Titan. It would be a water world because the ice would have melted. However, the planet is probably tidally locked, which means one side would be a large ocean and the other an ice world. What then should happen is that the water should evaporate, form clouds, go around the other side and snow out. That should lead to the planet eventually becoming metastable, and there might be climate crises there as the planet flips around.

So, could there be life? If it were a planet with a Saturn core composition, it should have many of the necessary chemicals from which life could start, although because of the water/ice live would be limited to aquatic life. Also, because of the age of the planet, it may well have been and gone. However, leaving that aside, the question is, could life form there? There is one restriction (Ranjan, Wordsworth and Sasselov, 2017. arXiv:1705.02350v2) and that is if life requires photochemistry to get started, then the intensity of the high energy photons required to get many photochemical processes started can be two to four orders of magnitude less than what occurred on Earth. At that point, it depends on how fast everything that follows happens, and how fast the reactions that degrade them happen. The authors of that paper suggest that the UV intensity is just too low to get life started. Since we do not know exactly how life started yet, that assessment might be premature, nevertheless it is a cautionary point.

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Exit Mugabe

I confess to having an interest in “important” people. What is it that makes them get to where they do? I have explored this in a number of my novels, and I have met and talked with a number of important people here, not that New Zealand is very important on the world stage, nevertheless I think I have seen enough to know that I don’t really know the answer. In Mugabe’s case, though, I think there were two major causes that brought him to the top. The first was self-belief and determination, and the second was stubbornness. Once he made up his mind on something, nothing would turn him away. And yet he has finally decided to quit.

He probably had little choice. The army did not want to have to shoot him, but eventually it must have occurred to him that the senior army officers could not back down and live. That is the sort of reality that someone like Mugabe would understand. The fact there were mass demonstrations may have finally got through to him, and now it must be galling that the crowds are cheering his departure. Still, he would know the usual exit for dictators is quite brutal, and there would be a time when the soft options would disappear.

Mugabe’s main positive claim to fame is that he led the Shona resistance to the white government the British colonial administration left as the government in Zimbabwe, or Southern Rhodesia as it was then called. For that he would get much gratitude from the Shona people, which would make him the obvious choice to become Prime Minister of the new government. It seems that at first he was reasonably enlightened, and expanded healthcare and education. Later, he would become President, but by then the signs were deteriorating.

This started when many of those of European descent fled, essentially for economic reasons. By itself, this was no great deal, however the skills they took with them was. It was the highly educated or those with money who could find a life most easily elsewhere. The economy started to contract, but Mugabe was not one to be put off his vision, and this is an unfortunate aspect with many dictators. They think their dream is the only one, and the reality of achieving anything is irrelevant. Means will be found, and they tend to shut their eyes at the consequences.

Worse was to come, because Mugabe now feared all those who had fought for revolution, and worse, there were scores to settle with the Ndebele. The Shona people hate the Ndebele for things that happened in the early 19th century, so then was the chance for revenge. To bolster his position, Mugabe ordered the training of the Fifth Brigade by North Korea, and set them loose on the Ndebele. Estimates are that there were 20,000 killed for no good reason.

Mugabe nominally was a Marxist, but he also realized that he should leave the economy working. Zimbabwe is naturally a rich country, and it was the breadbasket of Africa, and is also rich in minerals. The problem was, whites owned all the resources, so Mugabe set about confiscating them. The land seizures were declared illegal by the Zimbabwe courts, but Mugabe continued with them, declaring the courts irrelevant. Land was for Zimbabweans. It was all very well to put ill educated Shona as farm owners, but they did not know how to farm. Food became in short supply. Inflation soared to 7600%. Apparently, they even issued a banknote for 100 trillion dollars. But no matter how bad things got, Mugabe would not step down and let someone else try.

One of the bad aspects of revolution is that the people who carry out revolution are often not the best for what follows, and the history of revolutions is not a happy one. Not only that, but the leaders seldom if ever encouraged successors. South America was interesting because Jose de San Martin abandoned politics altogether after the successful liberation of the south, while Simon Bolivar did try to manage a major coalition of countries in South America and eventually gave up, leading to somewhat chaotic outcomes. The first Russian revolution was led by “nice” people who really had little idea what was required next, and we all know what Lenin and Stalin did to Russians.

One of the very few successful revolutions was carried out in America. What resulted after the British were ejected was a rather enlightened set of leaders who founded a truly great nation. And it is here that we see a great difference. This may sound awful, but in my opinion the best thing George Washington did as President was to step down after eight years. The reason I say it was the best is that while no doubt he did a number of other good things while President, they were relevant only at the time. His standing down and respecting the constitution, and I rather suspect he would have had the other option, has cemented that forever: no President would ever dare to suggest he was more important to the United States than George Washington, the man who effectively was responsible for it formation.

And here is Mugabe’s great failure: he could not put the country before his own personal wants. This was a tragedy. So what follows? Will Zimbabwe emerge into a bright new era? I am far from convinced prospects look good. The man replacing Mugabe is Emerson Mnangagwa, who was Mugabe’s “enforcer”, and was in charge of carrying out the killing of the 20,000 Ndebele. Not the most promising of starts. Worse, why the coup then? It appears that Mugabe fired Mnangagwa, and Mnangagwa had the generals behind him. You form your own conclusion.

Meanwhile, time for a quick commercial. This Friday, my new ebook, “The Manganese Dilemma” is released on Amazon. Russians, hacking, espionage, fraud, what more could you want over the weekend? Link: https://www.amazon.com/dp/B077865V3L

Asteroids

If you have been to more than the occasional science fiction movie, you will know that a staple is to have the trusty hero being pursued, but escaping by weaving in and out of an asteroid field. Looks like good cinema, they make it exciting, but it is not very realistic. If asteroids were that common, according to computer simulations their mutual gravity would bring them together to form a planet, and very quickly. In most cases, if you were standing on an asteroid, you would be hard pressed to see another one, other than maybe as a point like the other stars. One of the first things about the asteroid belt is it is mainly empty. If we combined all the mass of the asteroids we would get roughly 4% of the mass of the Moon. Why is that? The standard theory of planetary formation cannot really answer that, so they say there were a lot there, but Jupiter’s gravity drove them out, at the same time overlooking the fact their own theory says they should form a planet through their self-gravity if there were that amny of them. If that were true, why did it leave some? It is not as if Jupiter has disappeared. In my “Planetary formation and Biogenesis”, my answer is that while the major rocky planets formed by “stone” dust being cemented together by one other agent, the asteroid belt, being colder, could only manage dust being cemented together with two other agents, and getting all three components in the same place at the same time was more difficult.

There is a further reason why I do not believe Jupiter removed most of the asteroids. The distribution currently has gaps, called the Kirkwood gaps, where there are very few asteroids, and these occur at orbital resonances with Jupiter. Such a resonance is when the target body would orbit at some specific ratio to Jupiter’s orbital period, so frequently the perturbations are the same because in a given frame of reference, they occur in the same place. Thus the first such gap occurs at 2.06 A.U. from the sun, where any asteroid would go around the sun exactly four times while Jupiter went around once. That is called a 4:1 resonance, and the main gaps occur at 3:1, 5:2, 7:3 and 2:1 resonances. Now the fact that Jupiter can clear out these narrow zones but leave all the rest more or less unchanged strongly suggests to me there were never a huge population of asteroids and we are seeing a small residue.

The next odd thing about asteroids is that while there are not very many of them, they change their characteristics as they get further from the star (with some exceptions to be mentioned soon.) The asteroids closest to the sun are basically made of silicates, that is, they are essentially giant rocks. There appear to be small compositional variations as they get further from the star, then there is a significant difference. How can we tell? Well, we can observe their brightness, and in some cases we can correlate what we see with meteorites, which we can analyse. So, further out, they get significantly duller, and fragments that we call carbonaceous chondrites land on Earth. These contain a small amount of water, and organic compounds that include a variety of amino acids, purines and pyrimidines. This has led some to speculate that our life depended on these landing on Earth in large amounts when Earth was very young. In my ebook “Planetary Formation and Biogenesis”, I disagree. The reasons are that to get enough, a huge number of such asteroids would have to impact the Earth because they are still basically rock, BUT at the same time, hardly any of the silicate based asteroids would have to arrive, because if they did, the isotopes of certain elements on Earth would have to be different. Such isotope evidence also rules these out as a source of water, as does certain ratios such as carbon to chlorine. What these asteroid fragments do show, however, is that amino acids and other similar building blocks of life are reasonably easily formed. If they can form on a lump of rock in a vacuum, why cannot they form on Earth?

The asteroid belt also has the odd weird asteroid. The first is Ceres, the largest. What is weird about it is that it is half water. The rest are essentially dry or only very slightly wet. How did that happen, and more to the point, why did it not happen more frequently? The second is Vesta, the second largest. Vesta is rocky, although it almost certainly had water at some stage because there is evidence of quartz. It has also differentiated, and while the outer parts have olivine, deeper down we get members of the pyroxene class of rocks, and deeper down still there appears to be a nickel/iron core. Now there is evidence that there may be another one or two similar asteroids, but by and large it is totally different from anything else in the asteroid belt. So how did that get there?

I rather suspect that they started somewhere else and were moved there. What would move them is if they formed and came close to a planet, and instead of colliding with it, they were flung into a highly elliptical orbit, and then would circularise themselves where they ended up. Why would they do that? In the case of Vesta, at some stage it suffered a major collision because there is a crater near the south pole that is 25 km deep, and it is from this we know about the layered nature of the asteroid. Such a collision may have resulted in it remaining in orbit roughly near its present position, and the orbit would be circularised due to the gravity of Jupiter. Under this scenario, Vesta would have formed somewhere near Earth to get the iron core. Ceres, on the other hand, probably formed closer to Jupiter.

In my previous post, I wrote that I believed the planets and other bodies grew by Monarchic growth, but that does not mean there were no other bodies growing in a region. Monarchic growth means the major object grows by accreting things at least a hundred times smaller, but of course significant growth can occur for other objects. The most obvious place to grow would be at a Lagrange point of the biggest object and the sun. That is a position where the planet’s gravitational field and the sun’s cancel, and the body is in stable or metastable orbit there. Once it gets to a certain size, however, it is dislodged, and that is what I think was the source of the Moon, its generating body probably starting at L4, the position at the same distance from the sun as Earth, but sixty degrees in front of it. There are other metastable positions, and these may have also formed around Venus or Mercury, and these would also be unstable due to different rocky planets. The reason I think this is that for Vesta to have an iron core, it had to pick up bodies with a lot of iron, and such bodies would form in the hotter part of the disk while the star was accreting. This is also the reason why Earth has an iron core and Mars has a negligible one. However, as I understand it, the isotopes from rocks on Vesta are not equivalent to those of Earth, so it may well have started life nearer to Venus or Mercury. So far we have no samples to analyse that we know came from either of these two planets, and I am not expecting any such samples anytime soon.

A Giant Planet Around a Dwarf Star

The news here, at least, has made much of the discovery of NGTS-1b, described as a giant planet orbiting a dwarf star. It is supposed to be the biggest planet ever found around such a small star, and it is supposed to be inexplicable how such a big planet could form. One key point that presumably everyone will agree with is, a small star forms because there is less gas and dust in the cloud that will form the star than in the cloud that forms a big star. Accordingly there is less total material to form a planet. Missing from that statement is the fact that in all systems the amount of mass in the planets is trivial compared to the mass of the star. Accordingly, there is nothing at all obscure about an unexpectedly big planet if the planet was just a bit more efficient at taking material that would otherwise go into the star.

So, a quick reality check: the star is supposed to be about 60% the size of the sun, and the planet is about 80% the mass of Jupiter, but has a somewhat larger radius. Planets up to twenty times the size of Jupiter are known around stars that are not more than about three times the size of our sun, so perhaps there is more being made of this “big planet” than is reasonable.

Now, why is it inexplicable how such a large planet could form around a small star, at least in standard theory? The mechanism of formation of planets in the standard theory is that first gas pours in, forms the star, and leaves a residual disk (the planetary accretion disk), in which gas is essentially no longer moving towards the star. That is not true; the star continues to accrete, but several orders or magnitude more slowly. The argument then is that this planetary accretion disk has to contain all the material needed to form the planets, and they have to form fast enough to get as big as they end up before the star ejects all dust and gas, which can take somewhere up to 10 million years (10 My), with a mean of about 3 My. There is some evidence that some disks last at least 30 My. Now the dust collides, sticks (although why or how is always left out in the standard theory) and forms planetesimals, which are bodies of asteroid size. These collide and form bigger bodies, and so on. This is called oligarchic growth. The problem is, as the bodies get larger, the distance between them increases and collision probability falls away, not helped by the fact that the smaller the star, the slower the orbiting bodies move, the less turbulent it will be, so the rate of collisions slows dramatically. For perspective purposes, collisions in the asteroid belt are very rare, and when they occur, they usually lead to the bodies getting smaller, not bigger. There are a modest number of such families of detritus asteroids.

The further out the lower the concentration of matter, simply because there is a lot more space. A Jupiter-sized body has to grow fast because it has to get big enough for its gravity to hold hydrogen, and then actually hold it, before the disk gases disappear. Even accreting gas is not as simple as it might sound, because as the gas falls down the planetary gravitational field, it gets hot, and that leads to some gas boiling off back to space. To get going quickly, it needs more material, and hence a Jupiter type body is argued (correctly, in my opinion) to form above the snow line of water ice. (For the purposes of discussion, I shall call material higher up the gravitational potential “above”, in which case “below” is closer to the star.) It is also held that the snow line is not particularly dependent on stellar mass, in which case various planetary systems should scale similarly. With less material around the red dwarf, and as much space to put it in, everything will go a lot slower and the gas will be eliminated before a planet is big enough to handle it. Accordingly, it seems that according to standard theory, this planet should not form, let alone be 0.036 A.U. from the star.

The distance from the star is simply explained in any theory: it started somewhere else and moved there. The temperature at that distance is about 520 degrees C, and with solar wind it would be impossible for a small core to accrete that much gas. (The planet has a density of less than 1, so like Saturn it would float if put in a big enough tub of water.) How would it move? The simplest way would be if we imagined a Jupiter and a Saturn formed close enough together, when they could play gravitational billiards, whereby one moves close to the star and the other is ejected from the system. There are other plausible ways.

That leaves the question of how the planet forms in the first place. To get so big, it has to form fast, and there is evidence to support such rapid growth. The planet LkCa 15b is around a star that is slightly smaller than the sun, it is three times further out than Jupiter, and it is five times bigger than Jupiter. I believe this makes our sun special – the accretion disk must have been ejected maybe as quickly as 1 My. Simulations indicate that oligarchic growth should not have led to any such oligarchic growth that far out. My explanation (given in my ebook “Planetary Formation and Biogenesis”) is that the growth was actually monarchic. This is a mechanism once postulated by Weidenschilling, in 2004 (Weidenschilling, S., 2004. Formation of the cores of the outer planets. Space Science Rev. 116: 53-56.) In this mechanism, provided other bodies do not grow at a sufficient rate to modify significantly the feed density, a single body will grow proportionately to its cross-sectional area by taking all dust that is in its feed zone, which is augmented by gravitation. The second key way to get a bigger planet is to have the planetary accretion disk last longer. The third is, in my theory, the initial accretion is chemical, and the Jupiter core forms like a snowball, by water ice compression fusing. Further, I argue it will start even while the star is accreting. That only occurs tolerably close to the melting point, so it is temperature dependent. The temperatures are reached very much closer to the star for a dwarf. Finally, the planet forming around a dwarf has one final growth advantage: because the star has a lower gravity, the gas will be drifting towards the star more slowly, so the growing planet, while having a less dense feed, also receives a higher fraction of the feed.

So, in my opinion, apart from the fact the planet is so lose to the star, so far there is nothing surprising about it at all, and the mechanisms for getting it close to the star are there, and there are plenty of other “star-burning” planets that have been found.

Why has the monarchic growth concept not taken hold? In my opinion, this is a question of fashion. The oligarchic growth mechanism has several advantages for the preparation of scientific papers. You can postulate all sorts of initial conditions and run computer simulations, then report those that make any sense as well as those that don’t (so others don’t waste time.) Monarchic growth leaves no real room for scientific papers.

Politics and jail

The news this week is certainly attention grabbing. For my money, I suspect the most interest will fall on the indictment of Paul Manafort. I have read the indictments, and it is clear that while some of them are probably there for lawyer talk, there are two really serious ones. The first is he laundered money, at least $18 million worth, and maybe a lot more, and the second is that money mostly went for his personal benefit and he did not declare it as income. Tax evasion has been a classic way of sending bad guys to prison, an example being one Alphonse Capone.

The most obvious question to answer is, did he do it? If he did, it was not very bright of him to manage the US presidential campaign because politics, being what it is, sends too many people looking for a way to discredit you. Having committed obvious crimes, even if so far nobody has noticed, is an obvious weakness. The most obvious weakness is that Manafort is supposed to have avoided tax, but that also assumes he owned the money, as opposed to acting as an agent for the owner of the money. The indictment names a few properties, and I assume Manafort’s name will be on the property ownership papers as the owner. If so, he will be in trouble. However, he will be less so if he can prove he is merely an agent for the true owner. If he tries that, then he could be effectively admitting guilt to being an agent for a foreigner without registering, which is one of the other indictments. Interestingly, this appears to be being tried in a State court, rather than a Federal court. Does a State court really have jurisdiction over Federal matters? We await further developments.

One of the more interesting indictments is that he acted against the interests of the United States by carrying out contract work for Yanukovich, then President of Ukraine. Since when is it against the interests of the United States Government to carry out work for a democratically elected President of a foreign government that is not a declared enemy of the United States?

The other interesting issue is Catalonia. The Catalan regional parliament has voted to declare independence from Spain, on the basis that 90% of the 43% that voted in a nominally illegal referendum voted for independence. The Spanish Prime Minister, Mariano Rajoy, declared the vote and the declaration to be illegal, although what that means remains to be seen. The Catalan President, Carles Puigdemont, had paused and I thought he might even step away from going ahead with the declaration, but he has elected to declare seccession. Meanwhile, the UK, Germany and France have supported Spanish unity. So, what now? Puigdemont nominally faces up to 30 years in jail, but I doubt that that will be enforced unless something goes really wrong between now and then.

On the other hand, Madrid has apparently arrested a number of senior Ministers of the Catalna government who declared independence, and presumably they will try them in court. Puigdemont is apparently in Brussels, and claims he will not return to Spain until the threat of arrest is removed. Whether that will work is a matter of interest, but from Madrid’s point of view, they may not care. Puigdemont out of the way is probably just as useful to them and they do not want a political martyr.

Suppose the Catalans did secede, what would happen? The main “reason” for independence cited is to preserve the language, and to give a feeling of independence. They also feel that Catalonia pays €10 billion more to Madrid than it gets back in spending. Of course, not counted in that “paid back” are the services Madrid pays for, such as border patrol, customs, international relations, defence, a central bank, the tax service and air traffic control are some of them. As an independent country, it would have to set up these. There is also a sense of selfishness here; why should we send money to the poorer parts of Spain?

However, even in finance, there is a problem. The Catalan regional government owes €77 billion, of which about 2/3 is owed to Madrid. Then, of course, Madrid would expect Catalonia to share its proportion of the Spanish national debt. Further, two thirds of Catalonia’s exports go to the EU, and if Catalonia seceded it would be out of the EU, and would have to go to the back of the queue to get back in. Spain would then have the power of veto. Further, if it gained independence, it would have to leave the euro zone, and again Spain, and friends, could block re-entry. Either way, it would have to set up its own currency in the meantime. Of course countries like San Marino uses the euro without being an EU member with the eorozone’s approval, since they are so small. Nobody knows whether Catilonia would qualify, but Spain could block that. Apparently Kosovo and Montenegro use the euro without the EU’s approval. After all, a bank note is a bank note. However, a problem will arise if they ever need credit. If you use someone else’s currency, you have to earn it. Who knows what will happen?