Showing posts with label extinction. Show all posts
Showing posts with label extinction. Show all posts

Wednesday, July 22, 2015

How the Biological Sciences will transform everything... including life-span

Before commencing a rundown of amazing bio-wonder news, let's get back to the core matter at hand... waking up to the need to prevent a planetary collapse.

The Ocean Acidification crisis deepens. Writing in Science, experts say the oceans are heating, losing oxygen and becoming more acidic because of CO2.  If our future is more regions (the Caribbean and Mediterranean) becoming like the Black Sea, then we won't have to wait for sea levels to rise, before the oceans kill us in deserved revenge.

Denialist cultists out always scurry away and hide, or point and yell “squirrel!” whenever ocean acidification comes up. Because there are zero fox-narratives to evade this one.

The ocean has absorbed nearly 30% of the carbon dioxide we have produced since 1750 and, as CO2 is a mildly acidic gas, it is making seawater more acidic. It has also buffered climate change by absorbing over 90% of the additional heat created by industrial society since 1970. The extra heat makes it harder for the ocean to hold oxygen. Ocean acidification also causes shifts in the population of phytoplankton, which form the base of the marine food chain...some will die out, others flourish. 

FURTHER: that temperature rise could do what I fear most, cause a tipping point release of methanic hydrate ices along the ocean floor, turning the greenhouse into a runaway, possibly leading to a Green Sky. 

To see where this will lead, try fishing in today’s Black Sea… once-fertile waters that are now almost utterly dead.

So. Is the Anthropocene about to cause Earth’s Sixth Great Extinction?  “Using fossil records, scientists calculated a "natural" rate of extinction. For every 10,000 species, two go extinct every 100 years. In the past century, nearly 500 species have died off since 1900, rather than the nine that would be expected at natural rates.  Those include 69 mammals, 80 birds, 24 reptiles, 146 amphibians and 158 fish, and those figures are "highly conservative,"  a new report states.

Yes, be concerned!  Be passionate about this! I wrote about it back in 1988, in EARTH.  And yet… 

...and yet we are not quite at that tipping point.  All signs suggest that there is still some time. 

But we must act!

== Bioscience Updates ==

Bacteria as in situ cancer-detectors? Researchers have genetically modified E. coli bacteria into living sensors that can identify signs of diabetes and cancer -- capable of surviving inside a mouse's body for as long as a month.

Fascinating… if in desperate need of open-supervision… research now enables scientists to turn on-off specific clusters of neurons, making a mouse hungry or not, active or not.  An early result under President Barack Obama's 2013 BRAIN Initiative, which aims to advance neuroscience and develop therapies for brain disorders. The approach reflects a shift away from linking such illnesses to "chemical imbalances" in the brain, instead tracing them to miswiring and misfiring in neuronal circuits.

Great!  Only let’s do all this in the open, right? And it does make me wonder if the Goldman-Sachs AI overlords already have the ability to alter what I typ#&4,xosw2jpz88%$ gee I’m hungry. What was I saying? Never mind I gotta go to the fridge now…

Okay I'm back... and now...


Where was I before that sudden craving hit?

"Quantum Biology?" I used that phrase when I was twenty, as a joke in a very early sci fi novel. It got chuckles.  Not anymore. Researchers now see suspended, quantum bi-states in certain proteins involved in photosynthesis, possibly explaining nature's efficiency. Researchers now seek ways to incorporate the quantum lessons of photosynthesis into organic photovoltaic solar cells. Read further, how quantum effects may also be involved in the sense of smell... even consciousness!

Very interesting.  At least one aspect of aging might be the deterioration of bundles of DNA known as heterochromatin, which “spool up” portions of chromosomal DNA between uses, and a WRN protein that keeps these spools healthy. I'll wager we'll find these are already improved/more-effective in humans.

Also fascinating.  Active neurons seem to meddle in their own DNA.  “Scientists say they have discovered another mechanism used by neurons to maintain relatively consistent levels of synaptic activity so that neurons can remain responsive to the signaling around them.” 

A strange virus that can survive being boiled in acid could reveal how proteins and DNA can be put together in a way that's absolutely stable under the harshest conditions imaginable.


Promising...VirScan reveals your viral infection history in a single drop of blood. 


We’ve long known that DNA is made up of four nucleotides: A, T, C, and G -- adenine, thymine, cytosine, and guanine.  (A fifth – Uracil – replaces Thymine in RNA.) Now a fifth  DNA nucleotide may have been discovered.  It is a deviant of cytosine called 5-formylcytosine (5fC).  And has been showed to persist in low levels in the tissues of mice, suggesting it plays a small but significant role… probably in the regulatory portions of the genome (not protein expression.)  From the Futurism site.

Oh, and the first wholly new antibiotic to be discovered in nearly 30 years “has been hailed as a ‘paradigm shift’ in the fight against the growing resistance to drugs. Teixobactin has been found to treat many common bacterial infections such as tuberculosis, septicaemia and C. diff, and could be available within five years. But more importantly it could pave the way for a new generation of antibiotics because of the way it was discovered.” … using an electronic chip to grow the microbes in the soil and then isolate their antibiotic chemical compounds.


A single-celled marine plankton has evolved a miniature version of an eye to help see its prey better. “It contains a collection of sub-cellular organelles that look very much like the lens, cornea, iris and retina of multicellular eyes found in humans and other larger animals." Weird!

Intracellular processing of memory? I’ve argued with Ray Kurzweil over whether the synapse is the only seat of memory and computation in the brain… or if some kinds of information processing takes place within neurons and possibly glial cells. If so then “singularity” crossover – when digital computers will have the same number of elements as a human brain – gets pushed back many more Moore’s Law doublings.  Now come signs not only of intracellular computation, but that at least one variety may be mediated by “prion-like” molecules inside our cells.

== Keeping up with our AI Overlords? ==

In an earlier posting I mentioned that: "Elon Musk has funded the Future of Life Institute to explore possible failure modes re: Artificial Intelligence. (Indeed, I believe I have the cogent and persuasive argument that can get any truly advanced AI system to back off from any simplistic "kill all humans" or tun-everything-into-intelligent goo scenarios.)  But agin, yay Elon. We need a society that looks ahead."

Or else... will we find ways to keep up organically?  Wow… here’s one for the Predictions Registry.  In EXISTENCE I portray new computer methodologies freeing and empowering folks along the Autistic Spectrum to do valuable work… and this article tells how the Israeli Intelligence Services have carefully nurtured and developed this approach, employing spectrum folks for their meticulous attention to certain types of detail and pattern recognition.  Of course another variant on the theme can be found in Vernor Vinge’s A Deepness in the Sky.

Finally...


Looking back: See what your street in New York City looked like a hundred years ago in this interactive feature on Old NYC.


Friday, July 03, 2015

The Deadly Thing at 2.4 Kiloparsecs: Are we sharing the galaxy with something large, dangerous and periodic?

Never before online, this highly speculative piece was published in Analog Magazine way back in May of 1984. It won the Analog Award for Best Fact Article for the year. Some of the research may be dated...but the concepts still intrigue...

Note: This article mentions  the work of NYU's Michael Rampino who later on realized that Earth's major extinctions appeared to recur in cycles of roughly 26 to 35 million years.  He has an improved theory for that!  Indeed, despite involving Dark Matter, it is likely better and more plausible than the one I raised in this old Analog piece. Still, my hypothesis was unprecedented and certainly fits the observed facts... a deadly thing may indeed, still be out there, lapping us every... 200 million... or even thirty million or so! Certainly the concept deserves to be posted somewhere and available on the Inter-Tube.


Okay, then. To the way-back machine!

======  Dialing back to 1984... and here we go... =======

Mass extinctions are much in the news these days. Like a scandal long buried and only just being uncovered, the demise of the dinosaurs now seems to be only the uppermost layer of something far more regular – and deadly.

Several recent events have spurred this renewed interest in the ecological holocausts of the past. The most significant of these has been progress in the arcane art of reading the fossil records in ancient sedimentary rocks.

Paleontologists such as Dr. James Valentine of the University of California at Santa Barbara have been reconstructing the family tree of Earth’s living organisms, sorting which orders or phyla ended in extinction, and which branches evolved into new, competitive forms.

Some of the pieces of the puzzle seem, at last, to be falling into place. We now know, for instance, that the fall of the great reptiles – and the associated extinction of many marine forms – was not a unique event. Valentine and others report that there have been at least four, and as many as ten suspected mass dieoffs, in which large portions of the Earth’s biota – whole families, orders, and phyla – declined and then dropped completely from sight. In three of these cases, the evidence is statistically indisputable. These extinctions were indeed catastrophes which enveloped the entire Earthly ecosystem when they occurred.
  • At the end of the Cretaceous Period, approximately 65 million years ago
  •  At the conclusion of the Permian Period, about 185 million years before that
  •  And at the terminus of the Ordovician Period, approximately 210 million years further back in time.

The Great Die-offs

The Earth was far different in appearance each time it happened. Where the Cretaceous featured great reptiles and pre-placental mammals, the Permian was a time of tremendous fern forests and advanced amphibian forms. The Ordovician, on the other hand, featured hardly any life on land at all. But in each case the die-off was sharp and easily distinguished in the geological record. Suddenly, a large fraction of all the species at the time were wiped out.

Now (1984) Andrew Knoll of Harvard and Gonzalo Vidal of Lund University in Sweden report a fourth great extinction, at a time, 650 million years ago, when the highest forms of life were colonies of algae. This is about 200 million years before the Devonian event.
(Take note of the intervals between these major occurrences: 185, 210, and 200 million years. We’ll come back to them shortly.)

The paleontologists aren’t the only ones working on the problem of the past extinctions. A second discovery has received a lot of attention lately, adding another piece to our puzzle.
Led by Louis Alvarez of the University of California at Berkeley, a number of scientists have pointed out that some of the mass deaths are associated with unusual layers of clay – and that the layer representing the catastrophic end of the Cretaceous Period features astonishingly high abundances of certain rare isotopes.

Their conjecture is that a great meteorite struck the Earth, kicking up huge dark clouds and cutting off the sunlight. This supposedly then led to the ecological disaster observed in the fossil layers. Dust contributed by the vaporized meteorite supplied the unusual isotopes Alvarez and his team found in the Cretaceous-Tertiary boundary layer.

But the clay layer by itself is weak evidence for the falling rock conjecture. There are other ways to account for it. The abnormal isotope profile within that narrow layer is what the impact proponents rely upon most heavily.
But there may be another way to explain it.

Theories for Cycles

Veron 2008
Let’s go back to Fact One, the episodic occurrence of ecological disasters in Earth’s history. Would it not be interesting if there were some periodicity to these mass extinctions? If there were some pattern, then we might be able once and for all to assign a culprit … and incidentally know what to watch out for.

Recently two University of Chicago researchers, David Raup and John Sepkowski, have claimed that the four major and six lesser extinctions observed in the sediments seem to be part of a larger pattern that repeats at a rough average interval of 26 million years. They draw the implication that there is some repetitive process which puts the ecosystem of the Earth under stress in a regular pattern.

But even if the pattern they see is real, what sort of process could operate over such vast time scales, repeating reliably at 20 to 30 million year intervals?
Raup and Sepowski are not sure. Along with England’s Martin Whyte, they guess that the culprit may have to do with the interval workings of the Earth itself – with cyclic changes in the planet’s moment of inertia, its magnetic field, or the rate of transfer of heat to the mantle and crust.

It is an intriguing proposal, and it merits further investigation. However, there is a problem. No one can assign a clear-cut mechanism. Nor can anyone explain the dramatic difference between the six lesser and the four great extinctions.

One other potential periodic mechanism, that I discussed in the May 1983 issue of Analog, is the possibility that waves of settlement by starfaring civilizations might be responsible for episodes of extinction, followed by long periods in which the galaxy is empty of intelligent life. The theoretical time scales – 10 to 100 million years – seem to put this idea in the right range to be considered as a candidate, however it still remains pretty vague and hard to pin down. All we can do is catalog the hypothesis and move on.

The Major Extinctions

For the sake of argument, let us look at the four great die-offs alone … the four for which there is no dispute. Remember – 65, 185, 210, and 200 million years? Recall that these are fairly rough numbers. Nonetheless, one quickly sees the outlines of a pattern. If we assume we’re 65 million years into the latest phase of a repeating cycle, we might be tempted to guess that the greater die-offs occur at intervals of approximately –
197 Myr ± 12 Myr. (Myr = one million years.)

The uncertainty of 12 Myr is soft, but it is small enough to leave us encouraged that we may be onto something. It certainly looks like a pattern.

Could something periodic be causing this?
Not many natural processes occur with such regularity at such vast intervals. Only one cycle comes to mind with a periodicity similar to this. It is the revolution of the sun around the center of the galaxy … an orbit that astronomers now estimate to take approximately 238 million years.

 Might we be sharing the Milky Way with something deadly? Something that reaches out to “touch” our planet as we pass near it, roughly every galactic year?

Let’s pause and think about galaxies for a moment.
A spiral galaxy like the Milky Way does not rotate like a solid disk. Instead it is composed of many parts.
The galactic “halo,” like the core, consists of older, metal-poor, possibly planet-less stars of the first generation. In the halo the long, lazy orbits of solitary stars and globular clusters take them far out into the nearly empty territory above and below the spiral plane.

At the opposite extreme, in the galactic core, the crowded stars jostle and occasionally collide. They may even merge into super-compact bodies, giving rise to strange happenings. We shall speak more of these later.

Still, most of the really interesting things seem to be going on in the great, complicated disk of the galactic plane. Here the stars and gas and dust clouds rotate in their nearly circular paths, the inner zones finishing their orbits more quickly than those further out. This “differential rotation” is one of the things that drives the spiral design of our type of galaxy, helping to create the shock fronts where new stars are formed.

The shock fronts, along the concave faces of the spiral arms, are where clouds of gas and dust are compressed into new stellar systems. Some believe that life could not exist without these alternating zones of compression and release around the galactic rim. The sun’s orbit appears to meet one of the galaxy’s great spiral arms about every 110 million years or so. It takes about 10 million years to pass through one, about a million years alone to pass the shock front at the leading edge. We’re emerging from an encounter with the shock front of the galaxy’s Orion Arm right now.

Can one use these spiral fronts to explain the cyclical pattern of the mass extinctions? There are several theories which do make the attempt.
Source: NASA
W.H. McCrea contends that when the solar system moves into a shock region a sudden influx of gas and dust is absorbed by the sun, causing a dramatic increase in luminosity. That, according to the English astronomers Hoyle and Littleton, should increase precipitation on Earth, lowering sea levels and setting off a series of ice ages. 

The history of the last million years – featuring a series of ice ages only recently ended – lends the hypothesis some support. A related idea, by Napier and Clube, is that the galactic shock fronts are crowded with “planetesimals” like asteroids and comets, and that the sun regularly picks up a swarm of these every hundred million years or so, causing the Earth to regularly get “pasted.”

Or maybe the abundance of young, hot stars in the shock-front regions creates an area with a high incidence of supernovae (which would certainly wreak havoc on the Earth if one occurred close enough!)

All three mechanisms sound plausible, at least. Could the solar system’s periodic encounters with the spiral arm shock fronts then explain the major extinctions that have befallen life on Earth?

(2015 aside: Back in 1984 we didn't know the galaxy is "pleated" and that our solar system would rise and then dip through these pleats, several times during every 240 million year galactic orbit.)

Alas, the timing is all wrong.

Our encounter with the Orion Arm may indeed have triggered the ice ages of the ice ages of the Pleistocene, but the cycle of entering and leaving spiral arms clearly doesn’t fit the truly great die-offs of the Pre-Cambrian, Ordovician, Permian, and Cretaceous. The hundred and ten million year interval is over forty percent below the figure we calculated earlier – apparently way too low to apply to the major ecological holocausts of the past.

The Deadly Thing

If we re-examine the numbers just one more time, there does appear to be one more possibility – one more periodicity that no one seems to have covered yet. Our galactic orbital period.

We seem to be hit by something deadly every 195 million years or so. That’s similar to the 230 Myr solar orbit around the galactic center, but it’s clearly not the same. The 15% difference is enough to bother even the most impulsive pop theorist.

Until one realizes that anything truly dangerous floating about in our galaxy would itself have to be in orbit around the galactic center! With differential rotation, every distance from the center has its own unique orbital period, the sun’s happening to be 230 to 250 million years. There may be some “thing” co-orbiting with us – a little further out or closer in – the inner object “catching up” with the outer one at a period a little more rapid than one solar-galactic “year.”

It’s a problem that can be solved – roughly --  using the back of an envelope and a book of astronomical tables.

If the sun has, say, a period of 230 Myr, and we encounter “a thing” about every 197 Myr, then “Its” orbital period is solved by taking the difference of the two reciprocals (orbital frequencies) and dividing one more time.

If we do this, “It” turns out to have an orbital period of about 107 Myr.

We then go to the some of the tables of galactic rotation rates (laboriously collected by diligent astronomers, and published for the benefit of sleuths such as ourselves). The angular frequency versus radial function given in the literature is a little complicated, but when used carefully it gives a pretty clear result.

“It” has to orbit the center of the galaxy at a distance of approximately 2.4 kilo-parsecs, or seven point seven thousand light years. Our system, orbiting at about 10 kilo-parsecs, then has its nearest passage to the thing every 197 million years, as expected.

(2015 aside: note that if the extinctions cycle around 30 million years, that only shifts the orbit of the deadly thing inward, closer to the center of the Galaxy.)

Geological Astronomy

This is “geological astronomy” with a vengeance. We have just used the Earth as a great observatory, reading the sedimentary rocks like ancient photographic plates. Have we deciphered the clues correctly? Is there a Thing out there, which periodically catches up to use and does deadly mischief on our ecosystem with each near passage?

(Like many scientific discoveries or conjectures, this one has a haunting premonition in science fiction. In Poul Anderson’s Brain Wave, the die-off of the dinosaurs was caused by a beam which suppressed brain activity in the entire sector of the galaxy.)

If our Thing exists, it has to be pretty powerful, for according to our calculations we never pass closer to it than seven thousand parsecs. This means that it must somehow be selective, or act over a narrow angle.

The strongest possibility among known or modeled phenomena seems to be a rotating black hole which is emitting a powerful jet of sub-atomic particles.

The central cores of some spiral galaxies are extremely busy places, emitting awesome, energetic beams. SF author Gregory Benford (who is also professor of high-energy physics at the University of California at Irvine) has studied cases in which narrow, self-focused streamers of charged particles seem to be shooting narrowly across tens of thousands of parsecs, carrying as much energy as is being emitted from all the rest of the galaxy!

Clearly nothing like these monsters exists in the Milky Way today. But recent radio surveys have discovered an intriguing object, albeit much, much smaller – perhaps a fair to moderate black hole – very close to our galactic center. Radio-maps indicate a pair of jets several light years in length, spurting outward from the object.

(2015 note: this object has been confirmed to be our galaxy's central black hole, containing more than a million solar masses, and yet quiescent, at present, having long ago sucked in those objects whose orbits might bring them within grasp.)

In terms of modern galactic astronomy, this is small potatoes. But there may be others in the Milky Way, somewhere in between the sizes we’ve mentioned above. And one of these may be our culprit, now hidden behind the dust lanes of the galactic lens.
Source: Popular Science
Benford thinks the best candidate might be a condensed source projecting a beam of positrons and electrons, precessing and sweeping out a disk-like portion of the galactic lens.

An energy source like that would, indeed, be a deadly thing. An interstellar jet, even one barely grazing by the solar system, could explain a lot, such as the anomalous isotopes in those clay layers – if the particle fluxes were high enough to cause elemental transmutation. And it might be no problem for such a beam to overwhelm the ozone layer, causing collapse of the Earthly ecosystem.

Even if the beam passed nearby for only a brief time, it would probably be enough to do great harm. 

(2015 note: Rampino now sees the pattern as being roughly 30 million years.  This would be consistent with an object even closer to galactic center than my earlier hypothesized beast at 2.4 kiloparsecs.  Still, the basic idea here is not disproved.  It belongs on our shelf of possibilities.)

There you have it, still another explanation for a set of mysteries exhumed from under the dust of our ancestors. All the witnesses are long dead, of course. But that doesn’t keep us from sifting through the clues, looking for culprits.

Over the years we’ve heard conjectures of nearby supernovae, wobbling planets, and even colonization from the stars, in order to explain the demise of the dinosaurs and other mass-extinction victims. Though noe of them have rhythmic periodicity.

If the giant-meteorite proponents are right, we might be wise to take some precautions, to keep track of those bits of rock tumbling about the solar system. The other “periodic” solutions, too, each seem to offer their own bogey men to watch out for as well.

Now there’s this new “thing” to worry about, possibly orbiting out there roughly 2.4 kilo-parsecs from the center of the galaxy … just waiting, it would seem, to reach out one more time and get us.

It’s a little unnerving.

Still, one shouldn’t lose too much sleep over it. Dangerous and nasty as the little bugger may be, we probably have another 130 million years to get ready for it. If any money is going to go to chicken little preparations, at this point I think I’d rather spend it on asteroids.

Author’s final (1984) note: Remember where we mentioned TEN recorded ecological holocausts? This paper only dealt with the four greater die-offs, whose apparent regular intervals lead to an interesting conjecture.

But there are six much smaller events in the record as well. Of these, two are “intermediate” in magnitude – one about 80 Myr after the Ordovician disaster, and the other approximately 30 Myr after the Permian.

You can’t do much with two data points, of course. Certainly there’s no way we can imply that each major even is followed by a secondary die-off an average of 55 Myr later, is there?
It is now 65 Myr since the major holocaust of the Cretaceous…

No. The author steadfastly refuses to state that we seem overdue for one of those littler extinctions. That would be stretching things too far.

He hopes.

== ... back to 2015! ==

And there you have it.  A clever -- if somewhat unlikely -- rumination from my younger self.  The article was discussed on the Weird Astronomy page of the Atomic Rockets website: "...just because the assumptions are questionable does not mean that they are wrong."  This "lapping" mechanism has some appeal, whether applied to the thirty or 190 million year cycles.  Still, if wagering, I'd give stronger odds to some version of Mike Rampino's orbital "dipping" process... with or without the recent Dark Matter gloss.

And yet, aren't these marvelous times, as we sift for evidence and plumb the past for mysteries?  Our ancestors, if told of this quest, would be puzzled!

But the best of them -- I think -- would also be proud of us.

You should be too!  Try to get your fellow citizens to realize it, as well.