New life, and new life forms

Crash says: For some time I was entertaining the thought that Globular Clusters were indeed ARTIFACTS. Since then, I have realized that they might indeed naturally occur - as certain astronomers have tentatively begun to understand. But, wow, you get your telescope on M13 in Hercules and it just looks so perfectly symmetrical, it has to be by Intelligent Design.Ho ho ho ho.

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- xongsmith, 5.7d

I agree, nothing special at all. But our Sun's formation relative to the Big Bang may have been at precisely the right time so that the core temp of the universe could sustain galaxies, that can sustain solar systems, that can sustain planets, that can sustain life.Early galaxies, those closest to the Big Bang, would have found temp's too hot. Just as galaxies billions of years from now may find temp's too cold.- OniEdited by onifre, : No reason given.

I understand the need for time distance from the Big Puff.I also read that the Milky Way is thought to be in the oldest generation of galaxies, at about 13.6 billion years; our sun, 4.57 billion years.Let's set aside the rest of the universe for now, and consider whether we enjoy unique conditions in our own galaxy.From Wiki: Galactic habitable zone

quote:

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The location of a planetary system within a galaxy must also be favorable to the development of life, and this has led to the concept of a galactic habitable zone (GHZ), [17][18] although the concept has recently been challenged.[19]

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To harbor life, a system must be close enough to the galactic center that a sufficiently high level of heavy elements exist to favor the formation of rocky, or terrestrial, planets, which are needed to support life (see: planetary habitability). Heavier elements also need to be present, as they are the basis of the complex molecules of life. While any specific example of a heavier element may not be necessary for all life, heavier elements in general become increasingly necessary for complex life on Earth (both as complex molecules and as sources of energy).[20] It is assumed they would also be necessary for simpler and especially more complex life on other planets.

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On the other hand, the planetary system must be far enough from the galactic center that it would not be affected by dangerous high-frequency radiation, which would cause damage and harmful alterations to the DNA of any carbon-based life. Also, most of the stars in the galactic center are old, unstable, dying stars, meaning that few or no stars form in the galactic center.[21] Because terrestrial planets form from the same types of nebulae as stars, it can be reasoned that if stars cannot form in the galactic center, then terrestrial planets cannot, either.

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In our galaxy (the Milky Way), the GHZ is currently believed to be a slowly expanding region approximately 25,000 light years (8 kiloparsecs) from the galactic core and some 6,000 light years in width (2 kiloparsecs), containing stars roughly 4 billion to 8 billion years old. Other galaxies differ in their compositions, and may have a larger or smaller GHZ — or none at all (see: elliptical galaxy).

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So we have a theoretical habitable zone that is 2 kp x 8 kp, or 16 square kiloparsecs. Among the stars in that zone, our sun is relatively young (4.57 billiion years in a range of 4-8 billion years).It would appear that most of the stars in the Milky Way's 16 square kiloparsec habitable zone are older than than our sun.Note, in para 2 quoted above, that both the heavy elements required for carbon-based life and the necessary distance from the galactic center are taken into account.Why wouldn't many, if not most, habitable zone stars have supported the evolution of life, and possibly intelligence, billions of years before ours? Edited by Omnivorous, : Keep wanting to type inhabitable.Edited by Omnivorous, : 'rithmeticEdited by Omnivorous, : a tired brainEdited by Omnivorous, : No reason given.

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Have you ever been to an American wedding? Where's the vodka? Where's the marinated herring?!
-Gogol Bordello

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Real things always push back.
-William James

A series of concentric Dyson spheres around a star collecting all of the available electromagnetic radiation and doing some kind of complex activity with it, would be a good form of life. Multiple stars doing this and then networking those would be next. I suppose filling up a galaxy would be after that.

Hi, Omnivorous. Actually, that's not what it says. The galactic habitable zone is a circular band of stars of the same age. The 8 kiloparsecs figure was the radius of the circular region enclosed by the band, and the 2 kiloparsecs is the width of the band.So, the area should be:(pi)*(8+2)² - (pi)*(8)² = 113.1 square kiloparsecsThat's a lot of space.

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-Bluejay (a.k.a. Mantis, Thylacosmilus)Darwin loves you.

A thought from the nether reaches of the brain: Also: For this we have the Coyote Solution which is based on the premise, "Practice makes perfect unless you are doing it wrong." It is also based on the famous line from the first Indiana Jones movie, Raiders of the Lost Ark, spoken by Sallah: "They're digging in the wrong place!"The Coyote Solution is simple: If we can't find advanced alien civilizations it's because we're looking in the wrong place!If we can't detect advanced alien life forms, maybe it's because they're advanced, and are no longer communicating with smoke signals, which is what we have been scanning the horizon for.To this we can add the Coyote Rejoinder: Duh!Edited by Coyote, : No reason given.

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Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

I thought about the annular nature of the band while reading the Wiki text, then promptly ignored it; I'd've had to look up the formula anyway.
Thanks for the correction.

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Have you ever been to an American wedding? Where's the vodka? Where's the marinated herring?!
-Gogol Bordello

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Real things always push back.
-William James

Too long, I know, but I had fun so I really don't care.Let me introduce you to the Araneans.They are an intelligent species of the planet Perneaus about 2000 light years from Earth.The Araneans are a carbon-based life form whose genetic structure is DNA using different nucleic acids but much the same sugar backbone as in our structure in a circular rather than a spiral form. A major difference, however, is that in the Aranean evolution, their eukaryote ancestors had 4 nuclear organelles instead of one. The Araneans' cells contain 4 genetic nuclei, each with 8 circular chromosomes.The body plan of the Araneans consists of a bulbous abdomen about 1-1.5 meters in length supported on four legs, two on the front quarter, two on the back quarter on either side. The legs emerge horizontal from the abdomen then from the hi-knee down to the lo-knee at mid leg then down to the podiapad. At full extension the legs hold the abdomen about a meter off the ground.At the front end of the abdomen is a thorax which, similar to a long neck, can extend forward, but is usually held upward perpendicular to the axis of the abdomen. The thorax sports two sets of arms in the upper half of its meter length. The lower set of two arms, one extending out each side the thorax, have a similar form to the legs and each ends in a thick three-pronged claw which can be opened or closed. The upper set of arms (about 6-10 cm above the lower set) is similarly structured but end in four long (6-8 cm) jointed digits.Atop the thorax is the head which is usually spherical. Two compound eyes of six lens segment each are set in the upper hemisphere oriented toward the front but extending to the sides of the hemisphere. The compound eyes give the Aranean a 210 field of vision without moving. Swiveling the thorax gives the Aranean a complete 360 view with little effort.Since the star around which Perneaus orbits is a spectral type M star the energy of its main output is shifted further into what on Earth is called the near infra-red. The visible spectrum for the life forms on Perneaus is shifted in wave length 150 nm from what we know on Earth and extends from 850 nm in the red to about 650 nm. Aranean eyes are geared to these wavelengths.Below the eyes in the lower hemisphere is the proboscis opening or mouth and the olfactory assembly which consists of 12 short tentacles hanging (Zoidberg-like) from just above to just below the proboscis opening, about 3 cm.On either side of the head, just below the outer edges of the eyes are the ears. They consist of a spherical orb about the size of a golf ball sticking out of the head on the end of a short shaft. Each fluid-filled orb is composed of two nested spheres of collagen each covered with various length cilia. The cilia on the inner sphere are shorter then those on the outer sphere.At the back of the head, the remainder of both hemispheres is covered by usually 3 thick cranial ridges. Within the cranial cavity is a three-part cerebellum above the autonomic hind brain.At the top of the head are two antennae, flexible stalks about 4 cm long. They sense an additional set of infra-red frequencies from about 900 nm to 850 nm wavelengths. There are no structures on the antennae and no terminal bulbs. The antennae can be deflated under conscious control and recessed into the cranial shell. In recent times it has become fashionable to pierce the tops of the antennae with gold rings and precious stones.The Araneans are exo-skeletal. In their evolutionary history the first multi-cellular creatures incorporated silica from their environment for protective shells rather than make calcium carbonate as on Earth. The Araneans are covered head-to-ped, so to speak, with a hard silicate-impregnated fibro-collagen matrix.The top of the abdomen has natural ridges and patterns in a single shield. Before the use of genetic testing, carapace image was used as the main form of identifying an individual. The underside of the abdomen is covered with shell but is segmented over the mid-section covering the ovi/semen duct and at the end of the abdomen over the anal sphincter.The legs, arms and thorax are covered by movable segments of shell of various size. The face is covered by a thin segmented shell except for the around the eyes, olfactory and proboscis areas. The ear spheres are cover with a thin skin but have 10 small silicate spikes over their surface. The rear of the head is covered with a thick ridged shell.Araneans do not have lungs but respire through the skin on the thorax by waving the segments of silicate shell.Araneans are hermaphrodites. In pre-history an Aranean would sculpt a shallow oval about 20 cm long, 3 cm deep, in the dirt where it would deposit an oatmeal consistency goo as bedding. In modern times this is done in an ornate ceramic nesting bowl with elaborate ceremony in the presence of friends, family and the Chosen. It would then deposit two small ovi, each about the size of a lentil, onto the bedding making sure the two eggs are touching and receiving the witness of those in attendance that the bed has been properly prepared.It has long been taboo for an Aranean to fertilize its own eggs. The Chosen then moves over the nest and deposits a thick foam of semen. Depending on individual tastes and ability the Chosen sculpts the foam with highly intricate patterns and images much to the delight and approval of the audience and its mate. Each ovi contains one genetic nucleus. After each is fertilized the two ovi fuse into one individual with the necessary 4 nuclear organelles.The fetus grows and feeds on both the bedding and the foam taking in not just the nourishment but the silicates to build its shell segments. After about 6 months the movement under the now semi-hardened foam becomes agitated and the offspring pokes its head through the foam where, in a more party atmosphere with friends and family than ceremony, the new parents cut away the remaining foam and bring the new born out of the nest. Awe. Of course the first order of business is to inspect the carapace to verify the family lineage.Language for Araneans involves the clicking of the claws on the lower thorax arms, signs using the digits of the upper arms and the positioning of the antennae (usually to indicate tense, and in some dialects, inflection). For the vast majority of Araneans the left tri-claw is slightly larger than the right and makes a lower-pitched click. Using two of the three claw segments of either tri-claw makes a slightly softer click then using all three in unison.Araneans feed by protruding the proboscis out its opening, through the Olfactory tentacles, piercing the meat, fruit, vegetable then alternately releasing then sucking back strong digestive juices. Their history is unclear how or when the feeding orb was first used but some smart Aranean took something similar to a medium gourd, packed it full with its favorite mixture, sealed it back together, put a small proboscis sized hole in it and fed without any mess or spill.Today, home cooks have various sized feeding orbs for use. A typical meal is usually two medium orbs for various foods with various flavorings and a small dessert orb and what humans would recognize as a cup or glass for liquids. Of course mass produced polymer-based single-use food orbs are now readily available over many cultures on the planet.

Up to a point, but I don't think we can auomatically assume that there won't be a brick wall we can't overcome between current levels of technology and that required to engineer on a galactic scale. Simple tool use, after all, seems to have been around for many millions of years in all sorts of species, but it took the arisal of our species to turn this into the complex technology we have today. There could be an upper limit to our acheivements.Of course, it's also possible that galatic scale engineering just isn't acheivable full stop, due to basic physicl constraints on how much energy can be produced or how fast it's possible to travel.On the more general question of whether intelligent life would arise everywhere at about the same time, this seems very unlikely to me. Looking at the history of life on our planet, there seem to be certain jumps in its development. It's possible that, for most of the life's prescence here, there were no eukaryotic cells. Their creation could well be a bizarre and unlikely fluke, without which the biosphere would still just consist of varieties of bacteria.Given the vastness of the universe, the same fluke (or similar flukes allowing multicellular, inteligent life to eventually appear) could happen plenty of times, but happening at the same time seems unlikely even on geological scales. It might take 4 billion years on planet A, 1 billion years on planet B, 8.5 billion yearson planet C etc. etc.As for the Fermi paradox, the universe is huge! Why would we expect to notice evidence of civillisations unimaginably distant from us. We've only recently been able to (indirectly) observe the prescence of planets in other solar systems.

I wonder to what extent life could exist within stars (of various types) and interstellar ionic dust clouds. Or even 'lava monsters' within the molten cores of planets or moons. It would just be another type of molecular bonding, I guess.How could you identify life? On a certain scale Earth itself is alive, Gaia hypothesis. Subbie is the discussion about communicative 'intelligence?'Edited by CosmicChimp, : more stuff

No, not really. There is a reason we are a carbon-based life form and that same reason permeates the entire universe. It is the structure of the carbon atom.Carbon is the lightest element with four valence electrons. As such it can form flexible chains of itself with moderate bonds strong enough to be stable yet reactive under moderate energies. You can bend a chain of carbon around on itself forming a ring and still have connection points on the other electrons for bonding other elements like oxygen, hydrogen, nitrogen, etc. An excellent scaffolding for building complex molecular structures.The next element with this scaffolding capability is silicon, which is a considerably heavier element with stronger bonding strengths. It cannot be bent very much without breaking the bonds. It is brittle and tends to put a death grip on other elements. Its bonding strength is high and its flexibility is low.Sulfur, phosphorus and chlorine are even heavier, do not chain easily, if at all, and are highly reactive with some elements under low energies or bond too tightly to others. Their bonding strengths are too low or too high and their flexibility is near non-existent.When we look out into the cosmos we can see and identify by spectral analysis molecular structures in the interstellar medium. Last time I looked at the numbers we had identified around 6 sulfur compounds, fewer compounds of other elements and something around 86 carbon compounds.Because of its flexibility, stability and moderate reactivity carbon forms stable molecular compounds in abundance using less energy than any other element. If there is one thing we know about the universe it is that it will do things at the lowest energy state required. This is exactly what you need to build a complex chemical life system.All this does not mean that other life systems are not possible, just very highly unlikely.

What you've said is certainly true of earth-like conditions. Carbon-based life is probably the only kind of life living on earth-like planets, but what do you think to the notion that under very different conditions it might be that other chemicals become more suited. For example, under hot, high pressure conditions? Of which are knowledge is much more limited.

Well, I take your points. Obviously there's substantial room for a diversity of opinion on this stuff, and certainly tantalizing hints of extrasolar civilization (like the "Wow!" signal) indicate against my position.You know, but weird synchronicities do happen. Newton and Leibniz independently developed calculus almost exactly at the same time. Edison and Swan invented the same lightbulb.Just sayin'. Like I said I take your points. Well, they shouldn't be too distant. The Fermi paradox is that even assuming a relatively low rate of Earth-like planet formation, and even assuming a relatively slow rate of evolution of complex life forms, and even assuming wildly different timescales that intelligent life could evolve on, and even assuming the incredibly narrow span of time we've been able to look, we should still be up to our nutsacks in alien civilizations. Our galaxy should be a very crowded place but it's not. I suspect that's because we're the first ones to arrive at the party.

Not really. We know quite a bit about chemical reactions in high energy environments. That's why we can model the interior of blast furnaces , stars and planet cores. Under such extremes the high energies are available to break just about all chemical bonds regardless of the elements involved. Not good for a life system. Stability over an abundance of complex compounds is required or a life system cannot be started let alone be maintained.As I said prior, this may be possible, though we haven't seen any evidence of viability, but what we know of chemistry in high energy environments makes this highly improbable.Edited by AZPaul3, : No reason given.

Well I'd say for any in the Milky Way, it is possible. But this would support my initial opinion that they would have to have started about when life on Earth emerged.For early galaxies that formed, they were made up of mostly gas and dark matter, so fewer stars formed. And those stars that did form were of very high mass, and that type of star doesn't last very long - or rather, long enough to support a Earth-type evolution.But I'm just going by what I recall reading, so if anyone can confirm or correct my assumtions here that would be helpful.- Oni