Archive for the ‘Fermi Problems’ Category

Your Turn, Round 2-6: How to Escape From a Gas Giant

Between 2 and 3 years ago, I did a series of posts describing a sciencefiction setting of my own invention.  I was exploring different ways one might resolve the Fermi Paradox.  For those unaware, the Fermi Paradox goes like this: We observe many places in the universe where technological life could appear and persist; but we have no evidence of alien visitors to Earth.  Where is everybody?

The default solution to this paradox is to have technological life be rare in the universe.  Other possible solutions include civilizations encountering various problems; barriers that prevent them from traveling or sending robotic emissaries across interstellar distances.  So I call the setting “Fermi Problems” (geeky reference is geeky).

One situation I considered was life on a gas giant; specifically a hypothetical superjovian planet around HIP 66461, a G-type star 150 parsecs from the Sun.  Since HIP 66461 is in the section of sky allocated to the constellation Ursa Major, I called these hypothetical aliens the ursians and the planet Ursa.  I had thought that Ursa was a deep enough gravitational well that the ursians could never escape without outside intervention.  I may have been wrong.

So, How Do You Escape From A Gas Giant?

To go into orbit around a gas giant with 2.8 times the mass of Jupiter, you have to acquire a speed of at least 50 km/s.  Escape velocity requires twice the energy of the minimum orbital speed – i.e. 70 km/s in velocity, plus a bit more to account for the remaining gas drag.  That is very fast.

Read more…


Your Turn, Round 2-6: A Little Rapid World-Building – Tāwhiri

During a discussion I participated in elsewhere , science-fiction world building spontaneously appeared in a discussion of another subject when a couple of people brought up the example of floating forests / floating islands.  These have shown up in fiction before, and also in real life.  I was inspired to add them to the Fermi Problems setting.  When I had a notepad and a little time, I designed a planet to put them on and named it Tāwhiri.

What Is A Floating Forest?

When I say “floating forest” here, I mean a large mass of vegetation floating in a body of liquid.  Perhaps there is too much similarity here to the micro-gravity asteroid-surrounding forests and floating aerogel-clumps that already feature in the setting, but I will include it anyway.  It is relatively straightforward to produce a planet where such islands occur to a much greater extent than they do on Earth:

Consider an ocean gyre like the Sargasso Sea.  Have masses of floating seaweed-equivalent that grow densely enough and stack thick enough to give a portion of the mass that is persistently well above the water line – avoids the photosynthesizing bits getting shadowed by or eaten by other stuff growing in the water.  Then the clumps that are strong enough to avoid being disrupted by frequent waves/wind have a survival advantage, because they keep their energy supply more reliably.  To get something that looks like a terrestrial forest, rather than a lumpy-mat-berg-plant-thing, invoke selection for traits that keep the clump in the gyre and so at a good latitude for growing.  Growth dependence based on sunlight illumination patterns can do that, and progressively give “trees” with trunks and sail-leaves that adjust themselves unintelligently to take advantage of prevailing winds and stay in the gyre.

Some clumps will still escape, and either freeze in cold water or die in too-warm water or end up in another gyre.  Clumps that get too big will fragment during storms, some will have die-offs due to competition between the various species that accumulate to form the colonies, some may capsize and persist as dead-or-dying rafts that can be colonized by new growth, and so on.

Tāwhiri – A Waterworld

But how to make a planet where these floating forest-mats are the tallest-standing lifeforms?  We need to avoid having much land-based life to compete with.  We need a waterworld.

There is a problem with making a world that is entirely covered in water: Carbon dioxide emitted from the mantle during volcanism enters the atmosphere/ocean, and acts as a powerful greenhouse gas.  Unless it goes into making limestone or something similar, biosynthesis of carbon compounds only keeps so much of the carbon out of the atmosphere and only for so long.  On the Earth, weathering processes on rocks exposed to the air create carbonate rocks, which eventually get subducted and return the CO2 to the mantle.  If there is no exposed land at all, this process doesn’t work and the climate tends to run away into a steamhouse atmosphere, which is not conducive to abundant life.  So I will do a little fine-tuning on the volatile content.  The planet we are considering will have just enough water to cover all but 1% of the surface – we have various small exposed, largely volcanic, pieces of land; and larger relatively shallow areas of ocean that we would call submerged continental fragments if they were on Earth.  This is enough to give a stable climate, albeit one with more CO2 in the atmosphere than we humans can breathe:

  • Mass: 0.95 Earth masses
  • Insolation: 340 W/m^2 average.
  • Mean surface temperature: 300 K
  • Atmospheric pressure: ~1.1 atm, 0.01 atm CO2

That surface temperature is a few degrees hotter than Earth was during the Permian, and is such that there are no ice caps at the poles.  Some additional properties follow in part from the above and in part by arbitrary decision:

  • Host Star: Kiwi – 0.85 solar masses, 0.43 solar luminosity
  • a = 0.7 AU, year = 0.635 yr (291.4 local days)
  • Mean solar day: 19h6m.
  • Two satellites, each between 30% and 50% the mass of the Moon.

The relatively-shallow regions of the ocean also serve a useful setting function: they give a pattern of gyres and overall surface currents that is more-or-less fixed relative to the seafloor, rather than drifting around the planet.  Keeping the maps straight will still be annoying, but at least a given gyre will stay over the same geology.


I am also pleased to assume people living in/on these floating forest-mats.  Their cultures, history, anatomy, and evolution are not yet specified – this is a rapid once-through, after all.

But consider this technical problem: where do you get metal if you live on this world?  There are several possible sources: those few areas of dry land that do exist, sulfide or hydroxide deposits on the sea floor, and some manner of catalytic process that separates out the metals dissolved in the sea water.  The last has a terrestrial precedent: a ~3-cm snail called the scaly-foot gastropod that hangs out near some deep-sea vents:

Scaly-Foot Gastropod.  That shell is coated in iron sulfide.  via

Scaly-Foot Gastropod. That shell is coated in iron sulfide. via

So there are ways to start developing the hardware necessary to get off-planet and start expanding through space, although it would be somewhat more difficult than doing so on Earth.  I will have the inhabitants of  Tāwhiri in the Fermi Problems setting not have done this yet, in keeping with the large gaps in the setting between the number of places where life has appeared, the number of places where cultures have appeared, and the number of places where cultures have spread across large volumes.

Your Turn, Round 2-5: Conlanging

Continuing my series of posts of posts describing my Fermi Problems setting and encouraging you to find as many problems with it as possible:

Can You Tell Me What This Means?

Text handed to you by a neari mathematician.  You think they may be using base-12.  What does it mean? Note: the white blob in the outermost ring is a typo.

Text handed to you by a neari mathematician. You think they may be using base-12. What does it mean?
Note: the white blob in the outermost ring is a typo.

The context for this puzzle:

Some time ago, I came across Mark Rosenfelder’s Language Construction Kit. (now available in an expanded print edition).  As it says on the tin, it’s a guide to the process of conlanging: inventing, constructing, and using artificial languages for different purposes – specifically, for human or human-like communication rather than the more restricted languages used for sending instructions to and for communication between computer systems.  There is a fairly large community of conlangers, with its own internet fora, groups, and conferences.  And there are a lot of constructed languages.

Humans have deliberately constructed languages for many reasons: attempts (successful and not) to aid communication between each other either in specific circumstances or in general; to illustrate the different ways that languages can be structured; as works of art; as a language game; and as a way of adding to the world-building for science fiction and fantasy settings.  For fantasy settings, Tolkien was one of the first and one of the most thorough in his use of constructed languages in his world-building.  Appropriately for a scholar of languages and mythology, he designed the languages first, and then the mythology of Middle-Earth, and only then did he write the books.  Of constructed languages made for science fiction settings, Klingon is probably the most popular – to the point of having Shakespearean plays printed in the ‘original’ Klingon and having entire operas composed in it.

I’ve been playing around a bit with languages for various groups of people in the Fermi Problems setting, be they neari, ursian, human, or something else.  I showed a small sample of what I’m calling Clade-neari script in my concept art post a while back.  I’ve now added a bit more to the defined vocabulary, grammar, and syntax of Clade-neari (and also simplified a number of previously-defined glyphs).  I’ve been inspired by Rosenfelder’s kit, but also by learning a very little about how human sign languages work and by considering the different constraints imposed by neari anatomy and by the environments the neari live in.   Nearly all conlanging is done for speaking humans or at least for characters who are voiced by human actors.  Neari langauges, and the scripts that represent them, should differ from human languages (spoken or signed) in many different ways – although there will still be some similarities.

To judge how well I’m doing that, I’m going to be posting some script samples here.  Please tell me what you think of them!  This is both a language game and a world-building exercise.

An important note: in contrast to some previous language construction I’ve done, Clade-neari is supposed to be a naturalistic language and is not being designed to be easy to translate.  That said, this particular sample should be possible to translate without more formal discussion of the language here.  So, what does it mean?

Your Turn, Round 2-4: More Concept Art and A Note on Intellectual Property

Some time ago, I shared some ideas for a hard sci-fi setting I called “Fermi Problems”, outlining intelligent aliens that evolved in ecosystems in the atmosphere of a gas giant and in microgravity and zero pressure on asteroids.  We decided that I needed to move both of those ecosystems so that they were hundreds of lightyears from Earth, but that there were interesting possibilities for electronics make from material available in the atmosphere of something like Jupiter and some interesting technical innovations that were possible in microgravity.

At the time, I apologized for having relatively few graphics illustrating the setting.  I’m now trying to remedy that, at least for the asteroid-dwelling neari (sketching the gas-giant-living aerodynamic ursians has been harder for me).  So I now invite you to dissect my lack of artistic technique.

Before the pictures, a note on intellectual property:

I hereby make the neari, the ursians, and the entire Fermi Problems setting available to anyone who wants to use them for setting stories in.  Just let me know if you do – I want to read those!

Now, into the concept art:

Neari Bodies

This is a zoom-in on the body of the neari in the sketch that I posted before, showing the different structures on the various facets.

This is a zoom-in on the body of the neari in the sketch that I posted before, showing the different structures on the various facets.  Once again, this one has somehow gotten a can of Pringles.

Neari Claws

Illustration of a neari claw.  The inside edges of the three "fingers" are sharp, except for right at the joints (which can't be bent quite far enough to reach the base).  The structure between the bases of the fingers is a van der Waals pad, allowing the neari to hold onto a surface without muscle effort.

Illustration of a neari claw. The inside edges of the three “fingers” are sharp, except for right at the joints (which can’t be bent quite far enough for the tip of each finger to reach its base). The structure between the bases of the fingers is a van der Waals pad, allowing the neari to hold onto a surface without muscle effort.

Neari, Writing

This neari, being of a generation after the contact with humans, has become adept at writing on touch-screen computers.

This neari, being of a generation from after the contact with humans, has become adept at writing on touch-screen computers.  It’s looking at the screen using another of its visible-wavelength eyes, which can’t be seen from this angle.

Neari Writing

The neari have an appropriately large and diverse number of different languages and writing styles.  This is a sample of the partially-defined language and script that I designed for the neari that survived the comet-boat flight to Ursa.

The neari have an appropriately large and diverse number of different languages and writing styles. This is a sample of the partially-defined language and script that I designed for the neari that survived the comet-boat flight to Ursa.  You shouldn’t be able to figure out what it means from such a small sample, but feel free to guess.

Your Turn, Round 2-3: A Problem: The Drake Equation In This Setting

Frank Drake’s formula for estimating the number of intelligent civilizations in the universe that could be located by SETI efforts has some limitations.  But it does provide a convenient framework for thinking about the real search for extraterrestrial intelligence.  And it can also be used to see the implications for the Fermi Problems setting of having two intelligent species within 15 parsecs of Earth.

The equation: Number of civilizations in the galaxy N = (number of stars)*(number of planets per star)*(fraction of planets where life evolves)*(fraction of biospheres where intelligence evolves)*(how long intelligence lasts)/(age of the universe)

There are some modifications here from the usual form of the equation.  As I mentioned earlier, the usual definition of ‘intelligent’ for SETI is ‘having built a radio transmitter or other beacon readily detectable over interstellar distances’.  Here I’m using a more comprehensive definition, which includes humans anytime since behavioral modernity has been around.  And any one occurrence of intelligence lasts a long time.  As a starting point, call it 1 million years.

Several of the numbers in the equation are known.  The universe is 13.77 ± 0.06 billion years old, although I can round that to 10 billion for this because it takes a while for nucleosynthesis to work up to building enough non-hydrogen and non-helium material to make planets.  There are ~300 billion stars in the galaxy – although there could be somewhat more depending on how we count brown dwarfs.  The Kepler Mission and micro-lensing surveys show that there at least as many planets as there are stars.  Again, the accounting here is difficult: the surveys are generally not sensitive to planets smaller than the Earth (to say nothing of asteroids – although they should be massively down-weighted compared to larger objects).  Call the number of planets per star 3, to make the order-of-magnitude calculation easier.

So: In the Fermi Problems setting, N = 10^8 * (fraction of planets with life) * (fraction of biospheres that evolve intelligence).  There are ~1900 stars in ~1400 stellar systems within 15 parsecs of Earth right now.  If civilizations are uniformly distributed, which they may not be, for there to be two civilizations extant in that volume, there must be one civilization per ~700 stellar systems on average.  I can make it 1 per 1000 stars without straining the odds.  But N = 10^8 is 1 civilization per 3000 stars.  This poses a problem.

What Should I Do?

There are five different variables I can adjust in the setting.  The fraction of planets with life can’t be greater than one, and based on the evidence of our solar system it is most likely far less than 0.1.  I could say that biospheres evolve intelligence many times, making that fraction greater than 1. Counting the apes, the dolphins, the elephants, the canines, the cats, the parrots, the corvids, and some of the cephalopods as separate evolutions of intelligence on Earth gives 8, but we are obviously by far the most extensive of the lot.  It is pretty much impossible to get the product of those two fractions above 1, so I am left with three possible changes:

1. Intelligence lasts a long time.  I have had the ursians be trapped at the bottom of a hole in high-tech social stasis for hundreds of thousands of years.  Can I make it several million instead, to push the number up to 10^7 years?  This starts to get problematic for the neari, who can spread across 15 parsecs in that time even with limited technology; and technological stasis does not apply for them.  I don’t think I can push the lifetime up much further than that without the setting breaking.

2. There are more ‘planets’ per star.  In addition to terrestrials and gas giants, I count large satellites like Europa and Titan and some appropriately-down-weighted number of asteroids.  But, like the lifetime number, this can only go up so much.  Maybe we count 15 places in the solar system rather than 8, but most of those are less appealing for biologically interesting chemistry.

This leaves the last option, which is the easiest in scientific terms, but much harder in terms of plot:

3. Move the neari and the ursians further away from each other and from Earth.  Putting them each 150 pc away rather than 15 gives 1000 times as many stars.  Then, with civilizations lasting a million years and 3 planets per star, (fraction of planets with life)*(fraction of life with intelligence) need only be 0.001 or so.  In this version of the setting, one out of every 30 stars will have a biosphere near it somewhere – there will be strange microbes all over the place, and the nearest macroscopic ET organisms will be something like 30 lightyears away.  And in places with fossil records, there will be ruins/remains of billion-years-dead cultures; far far more of those than the extant cultures.

If I do increase the distances so much, then there is no way for a neari comet boat to travel to Big Bear and find the ursians.  And the timeline will need to be extended; with things involving humans and either group of aliens happening thousands of years in the future rather than only 500 years from now.

So, shall I change the setting to avoid the improbability of having not just two, but three civilizations so close together?  The price is much less of characters meeting aliens in person, much longer time lags when talking to aliens remotely, and much more far-future exoplanet geobiology and archaeology.  It seems that’s what the universe is like.