Posts Tagged ‘Super-Earth’

Super Earths Galore?

March 5, 2017

[Original research, as usual, explaining in a bit more detail the preceding essay, its allusions, and its background: I pointed out that Venus failed as a livable planet because of its different internal composition. I turn then that argument around to demonstrate habitable large “Super Earths” are perfectly plausible, because “Super-Earth” does not have to mean “Super-Gravity”. I ponder the reasons pushing some astrophysicists to be so dead set against Super-Earths, and track that to the usual submission to the present plutocratic Zeitgeist.]

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Usually, among astronomers, the term “Super-Earth” denotes a ROCKY planet with a mass higher than Earth’s. This does not imply anything about the surface conditions, habitability, or the potential presence of indigenous life.

In the Solar System’s icy gas giants Uranus and Neptune are 15 and 17 Earth masses respectively. My idea behind the concept of Super-Earths is to avoid “Gas Dwarfs”, also called “Mini-Neptunes”, by keeping the mass low enough.

What matters, to determine the livability of a rocky planet, is its surface gravity, and its composition regarding water and magnetism. It’s not as simple as Huyghens had it: “How vast those Orbs must be, and how inconsiderable this Earth, the Theatre upon which all our mighty Designs, all our Navigations, and all our Wars are transacted, is when compared to them.” -Christiaan Huygens (17th Century; Huyghens was financed by the tyrannical Super Plutocrat Louis XIV, an intriguing twist).

3,500 planets have been found around other stars (March 2017; the High Provence observatory found the first, and then the French satellite Corot found plenty, followed by NASA’s Kepler). A great percentage of them are Super Earths in the usual sense of being more massive than Earth, but less than Uranus.

In my terminology, a large Super Earth is not necessarily a gas giant. It may well be livable. (The reason to insist on all this is that I want money for super-telescopes, which are technically feasible, now; it’s just a question of money! If one listens to Siegel/Forbes below, one would decided to only finance financiers, since they pay more…)

According to my silicate composition argument, livable Super Earths with ten times Earth's mass are imaginable, because they could have Earth-like surface gravity... Astrophysicists paid by plutocrats don't think so (thus money is best spent on their sponsors... Instead of telescope!)

According to my silicate composition argument, livable Super Earths with ten times Earth’s mass are imaginable, because they could have Earth-like surface gravity… Astrophysicists paid by plutocrats don’t think so (thus money is best spent on their sponsors… Instead of telescope!)

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Ethan Siegel, a celebrity astrophysicist who writes for Forbes magazine, disagrees with the whole mood behind the concept of “Super Earth”.

Siegel claims that Super Earths are never habitable, let alone earthly: “There’s no such thing as a ‘habitable Super-Earth’. Earth is pretty much the limit of how large you can get and still be rocky. Anything much larger, and you’re a gas giant.

Bemoans Siegel: “For a long time, we thought our Solar System was the template for the planets we’d find in the Universe. Inner, rocky worlds dominate the hottest part of the Solar System, with large, gaseous planets orbiting much farther out. The largest rocky planet was Earth; the smallest gas giant was Uranus; the mass difference between the two was a factor of 17, with Uranus having four times Earth’s radius. So it was quite a surprise when exoplanet discoveries started rolling in. Not only can planets of various sizes and masses appear anywhere in a solar system’s orbit, but of all the mass-and-size combinations out there, the most common type of planet is one we don’t have at all: a Super-Earth.

May these worlds be home to the realizations of our extraterrestrial dreams? Ethan Siegel arrogantly nix the idea: “… a cold, hard look at the scientific facts — and at the physics behind planetary science — puts the kibosh on that in no uncertain terms. In fact, the most up-to-date science tells us that the very idea that there is such a thing as a “Super-Earth” is a failing on our part.

Imagining What's On The Left, Kepler 22 b as a livable Super Earth is a "failing on our part" say Forbes employed astrophysicists. Massive wealth inequality caused by lack of infrastructure, though is, presumably not a "failing on our part".

Imagining What’s On The Left, Kepler 22 b as a livable Super Earth is a “failing on our part” says Forbes employed astrophysicist. Massive wealth inequality caused by lack of infrastructure, though is, presumably not a “failing on our part”.

Ethan Siegel again:

“The planets that we’re searching for, ostensibly, are the ones that are the most Earth-like: with similar compositions, atmospheres, masses, temperatures and other conditions to our world. But until we actually find life on another world — or learn a whole lot more about these planets we’re only beginning to discover — we can’t be sure which conditions are mandatory for intelligent life and which ones are mere happenstance. When we classify worlds as Earth-like, we look to their radius and how much energy they receive from their star.

In the past, we’ve typically said that if these worlds are approximately the size of Earth and receiving approximately as much energy-per-square-meter as Earth, these are likely Earth-like worlds. But this was an assumption that we made prior to having enough data to draw a conclusion… thanks to follow-up observations of their pull on their parent star, we’ve obtained the mass for hundreds of these worlds. And the conclusion they point to is damning.”

The basic argument Ethan (and others from MIT, etc.) hint to is that Super Earths have such a high surface gravity, they hang onto considerable amounts of hydrogen and helium. Then the atmosphere becomes crushing, life can’t develop.

Professor Ethan claims, without iron-clad evidence that:

… the transition from “rocky” world to “gaseous” world occurs at just twice the Earth’s mass. If you’re more that twice the mass of Earth and you receive the same amount of energy from your star, you’ll be able to hold onto a substantial hydrogen-and-helium envelope of gas, creating an atmospheric pressure that’s hundreds or even thousands of times as great as what we have on Earth’s surface. The hope that Super-Earth worlds would be Earth-like is shattered, and we can safely put Super-Earths, Mini-Neptunes and Neptune-like worlds into the same overall category… it’s important to remember that even calling a world a “Super-Earth” is evidence of our bias. “

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All too many scientists tend to be biased about bias. Why the hysteria?

But I repeat myself: Ethan Siegel works for Forbes.

His preceding conclusion is, In My Not So Humble Opinion (IMNSHO), flawed: it depends upon surface gravity, hence hypotheses about a planet’s internal composition. Basically, those scientists scale up the composition of Earth to Super-Earth”. But we have no proof of that. Quite the opposite, we have indication to the contrary.  

I already talked about Venus. Venus is nearly Earth-size is Venus’ magnetic field is weak, and make the planet appear like a comet (observing with some instrumentation).

Venus shows us a probably different composition: it is less massive because it does have Earth’s heavy radioactive iron core:

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Primitive Mathematics & Geology Show Surface Gravity Can Be Low On A Super Earth:

The argument is that a Super Earth will have such a high surface gravity that it will trap an excess of hydrogen. Indeed, a planet with twice the radius of Earth will have eight times the mass of Earth. However this multiplication by 8 of its mass m is  true if, and only if, the Super Earth has the same density as Earth. Earth has density 5.5, due to a heavy iron core with density 10. Silicate rocks have only density 3.

If a Super Earth had the same exact composition as Earth, doubling the radius r would change the surface gravity, which is proportional to: m/rr. If m is multiplied by 8 and r by 2, one sees that the surface gravity is multiplied by 2.

However, if the Super Earth is mostly made of Silicates, its mass will just be multiplied by 5, not 8. Thus its surface gravity will only augment by 25%.

If now one considers a super Earth with radius three times Earth, one sees it’s volume will be 27 times greater, but, if made mostly of silicates, its mass will be no more than 15 times greater. Meanwhile 1/rr is roughly 1/10. So the surface gravity, would be only 50% greater.

Thus one sees that Super Earths with surface areas roughly ten times Earth are imaginable.

One could argue that a huge metallic iron core is necessary to create a large magnetic field protecting against radiation, in particular solar storms which may strip the atmosphere (as happened on Mars). And thus one could insist that the preceding is unrealistic that way. But we are sitting next to a mighty yellow star. Red Dwarves, although subject to flares, thus capable of ejecting radiation, may, overall, be less corrosive than Sol (as their energy output is relatively tiny).

The best way to make sure that we cannot have habitable Super Earth is to construct huge telescopes… That means high taxes in the financial sector, that useless vampire (Reminder: Obama brought in all the guys who had deregulated FDR’s financial safeguards, under Clinton in the 1990s; FDR had put those safeguards in roughly 48 hours after becoming president in March 1933!)

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A grander perspective: Why Is The Anti-Super Earth Crowd So Vociferous?

Ethan Siegel: “But if you insist on calling these worlds Super-Earths, the conclusion is inescapable: whether gaseous or rocky, a Super-Earth is no place for a human.”

I hope that considering my own logic, geophysical logic, Venus, Mars, the stridency of that conclusion is perceived to be unwarranted. Actually  Laura Schaefer of Harvard thinks that surfing on Super Earths is definitively a possibility. According to her computer simulations, it’s easier to have oceans and they last longer (ten billion years) on Super Earths with 3 to 4 times the mass of Earths… http://news.harvard.edu/gazette/story/2015/01/surfing-on-a-super-earth/

Let’s comeback to the strident enemies of livable Super Earths: they suffer from a known malady. This is the usual problem: to become stars, or super-stars, super-scientists jump to unwarranted super-conclusions which are bound to becoming “trending” on the “social networks”. There is little difference between that general mood of people sure of “The First Three Minutes” (who was measuring time, then? “God”, Dog, or super-physicists?) and “Allahu Akbar” (who told them Dog was great, Dog Himself? A friend of theirs?)

This is the moral flaw of (super) tribalism, the “Will To Power”, hubris unbounded, the ardent desire to become top primate, Super Baboon: it flushes, with neurohormones any other worries, makes one feel as if one were god. They all want to be like Obama, get it all, presidency, right of life and death onto the world, multi-billionaire friends, Nobel, etc. Just to forget their pathetic little condition on the Third Rock from Sol.

Well, the deepest thinkers are made of sturdier stuff. Build those telescope, and search for livable Super-Earths. They are out there. Tax those financiers behind Forbes and all plutocrats. Or, rather, tax their robots: most orders in the financial markets are passed by robots which trade in a way that leads the markets: 90% of the robotic orders to buy or sell are cancelled before being enacted.

Build telescopes, not cynicism!

Patrice Ayme’

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Where Is Everybody?

September 22, 2015

Where Is Everybody? This is the question Enrico Fermi asked in the 1950s, referring to the little green men who were supposed to inhabit the galaxy. This question is still with us. Efforts have been made to search for extraterrestrial life. Science Fiction books are full of worlds peopled by clever creatures.

It would be reassuring to know that the galaxy is full of clever creatures. After all, if we, human beings disappeared, well, we were just not good enough, no big deal: those out there, better than us, would pursue the mission we are named after, wisdom (sapiens in Latin).

Yet I see plenty of reasons why Earth’s advanced biosphere is unique. I go even further. In my opinion, the fact Earth has a radioactive, high density metallic core is crucial. I will reinforce this argument today (in light of just published research).

Weirder Planets Than We Ever Imagined Are Out There. Yet, Weirdest Of Them All Could Be The Earth

Weirder Planets Than We Ever Imagined Are Out There. Yet, Weirdest Of Them All Could Be The Earth

Fermi, Nobel for discovering the neutrino (“little neutron” in Italian), discovered the Fermi principle and statistics (which posits that matter does not collapse because Fermions refuse to be in the same “state” in the same place at the same time). Fermi, who had fled from fascist Italy, was also the scientific head of the Manhattan project.

Fermi was both a theoretician and an experimentalist. Thus immensely clever, but yet down to earth. He obviously found that the obvious absence of civilization out there in space was a striking fact. And it is.

The idea that the stars had little Earths orbiting them, graced with little green men, with their own little green Christs, came all the way back to another Italian, Giordano Bruno. Bruno had lectured in universities around Europe, and was a friar. However, to suggest the world was not exactly as Christianism described it, was a capital crime in places ruled by Christianism.

To punish Bruno’s mental exuberance, the Vatican imprisoned and tortured him for seven years. Then the Vatican and its horrid Fundamentalist Jihadists stripped Bruno naked, pierced his palate with iron (so that he could not address the public), and burned him alive after he refused to submit to infamy. I am still waiting for the excuses from the institution at fault, the world’s oldest, the Catholic Church.

Yet, although he was a genius, Bruno was probably wrong about the little green men. Why? Where is everybody? Indeed. I argued that the nuclear reactor at Earth’s core has been crucial for plate tectonics, and preserving Earth from the runaway greenhouse which destroyed venus as a potential biosphere. I even argued that said nuclear reactor may have generated the Moon, by far the largest satellite in the Solar System relatively to the size of the planet it orbits around. (The Moon is larger than Jupiter’s third largest satellite, Europa.)

To generate a large radioactive core to a planet, one needs, first of all, metals. Actually metals enable to make very complicated molecules central to the wealth of biology. Hemoglobin carries iron which is used to transport oxygen.

Where do metals come from? Supernovae.

Which type of planets do we expect to observe in the Habitable Zone?

Vardan Adibekyan, Pedro Figueira, Nuno C. Santos

(Submitted on 8 Sep 2015)

“We used a sample of super-Earth-like planets detected by the Doppler spectroscopy and transit techniques to explore the dependence of orbital parameters of the planets on the metallicity of their host stars. We confirm the previous results that super-Earths orbiting around metal-rich stars are not observed to be as distant from their host stars as we observe their metal-poor counterparts to be. The orbits of these super-Earths with metal-rich hosts usually do not reach into the Habitable Zone (HZ), keeping them very hot and inhabitable. We found that most of the known planets in the HZ are orbiting their GK-type hosts which are metal-poor. The metal-poor nature of planets in the HZ suggests a high Mg abundance relative to Si and high Si abundance relative to Fe. These results lead us to speculate that HZ planets might be more frequent in the ancient Galaxy and had compositions different from that of our Earth.”

So the (empirical) argument is that, if a planet has metal content similar to Earth, it orbits so close to its parent star that it will be too hot for life. Reciprocally, planets which orbit in the Habitable Zone are found to be metal poor.

Planets are built from the same elements as their stars. Most of the properties of planets of different types strongly depend on their host stars’ chemistry, and chemistry varies. It seems Habitable Zone planets were formed long ago. After supernovae formed and exploded, spewing heavy metals such as Iron and Uranium, second generation stars such as the Sun formed, and were metal rich. However, the observations on hundreds of planets tend to show that metal-rich stars like our sun have large rocky planets wrapped in huge gaseous envelopes (caveat: it may still be a bit of a statistical fluke, at this point!).

If not a fluke (and that’s a big if), it gives a new reason to doubt that Earth-like planets are frequent in the galaxy: I argued that not just metal, but the very heaviest metals, the ones which have such large nuclei that they fission, are indispensable for life. Now it turns out that Earth orbits a metal rich star, but at a respectable distance.

So it may well be that Earth is a very special case. Maybe some day the Galactic Human Empire will be able to colonize habitable planets in various Habitable Zones, because thanks to human technology, humans, or, rather, transhumans, will capable of synthesizing metals, as needed (one could do this, if one had a mastery of accelerator technology to fine-tuned nuclear fusion as needed).

Philosophically, this rarity of Earth’s circumstances tells us, once again, that life is more precious that we ever imagined. It’s not just our unborn great grandchildren who will suffer from the holocaust of the biosphere we are engaged in. It’s the universe itself, because we may well be that unique.

Patrice Ayme’