Methane-Based Life Possible On Titan

ratamacue0 sent me this interesting Slashdot post: Methane-Based Life Possible On Titan – Slashdot.

Randym writes:

With the simultaneous announcement of a possible nitrogen-based, cell-like structure allowing life outside the “liquid water zone” (but within a methane atmosphere) announced by researchers at Cornell (academic paper) and the mystery of fluctuating methane levels on Marsraising the possibility of methane-respiring life, there now exists the possibility of a whole new branch of the tree of life that does not rely on either carbon or oxygen for respiration. We may find evidence of such life here on Earth down in the mantle where “traditional” life cannot survive, but where bacteria has evolved to live off hydrocarbons like methane and benzene.

There’s a lot in this post, all relating to life and methane.  The first is about a study of possible life that might exist in liquid methane (instead of water), which is a possibility in the outer solar system, notably on Titan, a moon of Saturn and the largest one in the solar system.  The average temperature on Titan is about -179 ºC, below the boiling point of methane.  On Titan, methane may flow like water does on Earth, in rivers and lakes.

The idea that there may be methane life in the universe has been around for a while.  The new model seems to lend some support to the idea, but I think it’s important to understand that this is only a hypothetical model.  If methane based life does exist on Titan, I wonder at what stage it would be in its evolution, since life is chemistry, and chemistry at -179 °C (94K) seems like it’s going to flow a lot slower than chemistry at 15 °C (288K).  If there is life on Titan, I think it’s likely still in the relatively early stages.

Mars is cold by our standards, but it’s not far enough from the sun to be cold enough for liquid methane.  Methane is a gas there, just like it is here.  My understanding is that the significance of methane there may be as a possible waste or by-product from some kind of life, much as it is from some life on Earth.  The methane on Mars may still be from non-living natural processes, like volcanoes.  Only time will tell.

The article on life in the lower levels of Earth’s crust is interesting.  I think it got included here because that life may feed on chemicals like methane.  Again, this is different than what’s being envisioned as a possibility for life on Titan, but still pretty fascinating, particularly the possibility that life may permeate down into Earth’s upper mantle.

I think all of this goes to show that we have reasons to believe that life can exist in a wide variety of environments, and that only looking for it in narrow habitat zones may be too limiting.  Personally, given the wide variety of what we call “life” here on Earth, I suspect that when we do find the first extraterrestrial life, it may well challenge our very conception of what life is.  We may end up debating whether or not it actually is life, or just some kind of previously unknown complex chemical processes.

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RIP, Leonard Nimoy


As a Star Trek fan, I’m saddened to hear that the person I’ve always seen as the face of that franchise is gone. But I take consolation from the fact that he did live long and prosper.

Originally posted on Whatever:

He passed away today at 83.Here’s the New York Times obituary. Doubt there are many people in the world who were so plainly and simply admired as he was, and is.

And rather than to be entirely sad about the end of a life lived well and prosperously, here’s a couple of music videos for you.

Rest in peace, Leonard Nimoy. We are, will always be, your friends.

View original

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SMBC: Apologies by discipline


Click through for full sized version.

via Saturday Morning Breakfast Cereal.

Anyway, apologies are an evolutionary survival mechanism and therefore just an illusion.


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Shoulder update, hopefully the last

Just a quick follow up on my previous shoulder update post on my recent shoulder pain struggles.  The second doctor thought the surgery recommendation was premature.  He recommended conservative treatment, including a cortisone shot and physical therapy exercises, followed by a second shot in a month or two, if needed.  Only if problems persisted after that would he recommend considering surgery.  So, that’s what I’m doing.

I’ve been grateful for the well wishes and concern from many of you, my online friends.  Thank you!

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A close pass by a red dwarf star, and a note on interplanetary and interstellar distances

First, in case you haven’t heard: 70,000 Years Ago, Another Star Flew by the Edge of the Solar System | RealClearScience.

According to an international team of astronomers, about 70,000 years ago a red dwarf star — nicknamed “Scholz’s star” for the astronomer who discovered it — passed by our solar system just 0.8 light years distant. In fact, 98% of the 10,000 simulations the team ran projected that the star’s path grazed the outer edges of the Oort Cloud, a region of space filled with icy planetesimals which marks the final boundary of our solar system.

…Scholz’s star is now twenty light years away and won’t be returning anytime soon. However, Dr. Coryn Bailer-Jones of the Max Planck Institute for Astronomy calculates that we may receive another visitor in the distant future. Last December, Baller-Jones reported that the rogue star HIP 85605 may pass as close as .132 light years to the solar system between 240,000 and 470,000 years from now. That’s a close miss on the cosmic scale, but more than far enough that our futuristic ancestors will have little to worry about. The only concern would be that HIP 85605’s foray through the inner Oort Cloud might send a few comets careening in Earth’s direction.

This is interesting and just goes to show that, on a large enough time scale, assuming we don’t drive ourselves extinct, humanity will eventually be able to go to the stars, even if we have to wait for other stars to occasionally come near us.  (Not that we could make such a trip with current technology, but it’s a lot easier than reaching the nearest current star.)

That said, it’s important to keep in mind what “near” means in this context since some news outlets are saying the star passed “within” our solar system, implying to most people that it passed near the planets or something.  As Pomeroy notes, this pass was 0.8 light years away.  While it’s less than a fifth the distance to the current nearest star (Proxima Centauri), that’s still over seven trillion kilometers, over 52,000 times the distance between the Earth and the Sun, or more than 1300 times the distance to Pluto.  Even the star HIP 85605 mentioned above that might some day pass as close as 0.132 light years away will still be more than 200 times the distance of Pluto.

Saying that these near passes are within our solar system is only accurate if your consider the solar system to encompass the theoretical Oort Cloud, thought to be a cloud of icy rocks that extends as far as 2 light years away, or half the distance to the next nearest star.  While some might argue that the phrase is accurate, it’s a far broader meaning of “solar system” than most people are familiar with.

It also illustrates that, as large as the solar system is, and it is incomprehensibly large by any human scales, it’s essentially the outer layers of the Sun when seen from interstellar distances.

Space is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.

Douglas Adams, The Hitchhiker’s Guide to the Galaxy


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Twelve Angry Philosophers – Existential Comics

Click through for full version.

continued at Twelve Angry Philosophers – Existential Comics.

I think the final panels in the full version represent the end result of most philosophical debates.  Not that we shouldn’t have those debates, but we should be conscious of the fact that many philosophical problems have no authoritative answer.  Some, and this may include the most interesting questions, may never have one.  Indeed, once it’s possible to have an authoritative answer, it’s usually then in the purview of science rather than philosophy.

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Religion, the Axial Age, and theoretic culture

ReligionInHumanEvolutionCoverI recently read the late Robert Bellah’s ‘Religion in Human Evolution: From the Paleolithic to the Axial Age.’  Although the title of the book seems to narrow it to just religion, in ancient societies, religion was just about everything, so the book ended up being about the development of cultures, which isn’t too surprising given Bellah’s background in sociology.

One of the topics Bellah covers is Merlin Donald‘s concept of theoretic culture, that is culture that includes thinking about thinking.  The idea is that world religions, philosophy, science, and other forms of relatively advanced thought are aspects of theoretic culture that developed during the Axial Age.

Bellah discusses different stages of cultural transmission.  Each builds on the previous ones, with theoretic being the final one.

The earliest stage, which strictly speaking isn’t really cultural transmission but it’s a crucial building block, is episodic memory, that is remembering specific events and situations and recalling them when encountering similar new events.  Episodic memory is evolutionarily ancient, going back hundreds of millions of years.  It added the ability for an animal to respond to situations outside of their instincts.

Not nearly as ancient, but still very old, is mimetic culture, the ability to observe what others are doing, learn from it, and adopt it for your own use.  Mimetic culture is most developed in social animals, particularly in primates, and of course most thoroughly in humans.  Long before language, primates observed each other and learned from their actions.  For example, in a tribe of chimpanzees, when one figures out a new way to use a stick to find food, other monkeys observe and adopt the technique, and it becomes part of that tribe’s culture.

It’s from mimetic culture that ritual arises.  And ritual forms a core aspect of Bellah’s thoughts about religion.  Ritual predates religion and, in Bellah’s conception, lies at the center of it.  Ritual is a core part of the enactive aspect of religion, the part that makes the religious beliefs feel real.  It’s also why many other ritualistic aspects of culture, such as civil ceremonies and sports events, often have a borderline religious feel to them.

On top of mimetic culture, we have narrative culture.  (Many call this “mythic culture”, but Bellah prefers the more value neutral term “narrative”.)  Narrative culture, the transmission of cultural information through stories, is almost certainly as old as spoken language.  It’s the predominate form of cultural transmission in oral cultures, that is, cultures that aren’t yet literate.

Bellah refers to pre-axial state cultures, such as ancient Egypt, Sumer, and Akkad, as archaic societies.  He emphasizes that those that had writing remained largely oral in orientation.  Reading and writing in cuneiform and hieroglyphics were complex, difficult, and reserved for a small class of professional scribes.  The majority of these cultures, even among the elite, were still oral.

(I’d never realized this until reading Bellah, but this is why virtually all of the earliest literature is poetry or chants.  Stories told in meter were much easier to remember.  The oldest sagas were almost all orally composed, including such epic poems as the Iliad or the saga of Gilgamesh, or aphoristic collections such as the Vedas.  The oldest writings were recording oral information then widely in circulation.  Prose only begins to proliferate when literacy starts to become more pervasive, at least among the ruling classes, when there is an audience that will be able to read it without having to commit it to memory.  And that only happens with the prevalence of relatively simple writing systems such as the Phoenician and Greek alphabets.)

As archaic societies developed, they began to engage in what Bellah calls mytho-speculation.  This is not just repeating and recording oral mythologies, but speculating about how the world is put together, about the attributes of the gods, and other aspects of reality.  This became prominent in the Egyptian New Kingdom with the rise of theological writing, particularly in the fascinating case of the pharaoh Akhenaten, who attempted to found a new monotheistic religion in Egypt, developing the idea of his god, Aten, in a mytho-speculative manner.

Bellah never explicitly defines mytho-speculation, but I interpret it as someone consciously pondering reality (either sincerely or manipulatively), rather than merely repeating traditional stories that evolved organically across generations and centuries.  Bellah argues that the people later retroactively defined as the pre-Socratic philosophers (that is, Greek philosophers before Socrates), were actually more engaged in mytho-speculation than theoretic culture, that the earliest pre-Socratics didn’t attempt to justify their speculation, they just engaged in it.  Given the very limited knowledge we have of these early pre-Socratics, I think we have to be cautious in categorizing them, but it stands to reason that thought would have evolved through stages.

It’s in the Axial Age that, Bellah argues, theoretic culture arises, that is, culture that thinks explicitly about how to think.  Bellah identifies the pre-Socratic philosopher, Parmenides as providing a major breakthrough in Greek culture by developing the philosophical argument.  (See Michelle Joelle’s excellent recent post about philosophical arguments.)  What Permenides introduced, Plato more fully developed, and theoretic culture was established in Greek society.

Of course, it wasn’t only in Greece that theoretic culture arose, but also in India with Buddhism, and in China with Confucianism.  This is why this period is called the Axial Age.  (That and the fact that it happens to sit at the mid-point, the axis, of written history, roughly equidistant between the development of writing and modern times.)

I’ve written before that I think the rise of simple phonetic alphabets was what led to the Axial Age, at least in the west.  I’ve read other speculation that it might have been from increases in agricultural production that led to larger surpluses than what had come before, allowing for a larger intellectual class.  I suspect there were multiple causes that reinforced each other.  But, interestingly, Bellah and other scholars seem to think that writing was a result of the Axial Age rather than a cause.  I’m not entirely sure the chronology bears that out, except possibly in India, where post-Harappan writing apparently didn’t get off the ground until after the Axial Age.

I’m also not entirely sure that we can even say that theoretic culture didn’t exist before the Axial Age.  It’s just the earliest time that we have evidence for it since it’s the time that literacy starts to become (relatively) widespread and opportunities for that evidence to be recorded become pervasive.  Who knows what the thinkers in ancient Egypt or Sumer thought, or how much the Greeks might have owed to and built upon their ideas?  It’s worth noting that although writing goes back to around 3000 BC, studying history before the Axial Age is mostly an archaeological exercise, but becomes much more about studying historical documents afterward (again, at least in the west).

But I don’t think there’s much doubt that theoretic culture became far more advanced, as the thoughts of thinkers began to be recorded, read by later thinkers, and built upon in a way far more sophisticated than was possible in oral cultures.  It ushered in a new age of human cognition.

But it’s not like we crossed the theoretic divide and achieved cultural maturity in the Axial Age.  As I’ve written about before, science in particular looks very different today than it did only 400 years ago.  We may have begun the theoretic journey c. 500 BC, but we are still definitely on it, and with the breakneck advances in communication, such as the internet, we may well be entering a new axial age.

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