The stellar forges

A criticism sometimes aimed at us science types is that our obsession with naming, classifying, and explaining everything in the universe robs us of its wonder.  Why, they ask, do we have to get so damn technical about everything?  Why can't we just look at the stars, or the flowers, or a bird in flight, and appreciate their beauty?

Well, needless to say, I disagree with that pretty strenuously.  My understanding of science -- which, admittedly, is that of a reasonably well-read layperson's -- only adds to my sense of wonder.  For me, it's a case of the more you know, the more amazing it gets.

Let me give you an example of that -- a piece of research out of the University of Arizona that used the James Webb Space Telescope to peer far out into space (and thus, far back in time), and found something astonishing.  Something, in fact, that would appear quite mundane, meriting only a "So what?', if you didn't know some science.

Here's a capsule summary of the research -- then an explanation of why it's way cooler, and more surprising, than it appears at first.

The JWST just released a spectral analysis of a galaxy called JADES-GS-z14-0, which is about 13.5 billion light years away.  That's a pretty impressive feat; this means the light from it left on its journey to us when the universe was only two percent of its current age.  This, in fact, means the galaxy itself formed not long (in astronomical terms) after the cosmic microwave background radiation, the earliest remnants of radiation released when the universe settled down enough to allow photons to travel unimpeded.

Just seeing JADES is amazing enough.  "Imagine a grain of sand at the end of your arm," said Jakob Helton, who led the research.  "You see how large it is on the sky -- that's the size of the region we looked at."

The shocker came when they did an analysis of its spectrum, and found that it had high amounts of oxygen.  But why this is surprising -- why, in fact, it's going to force a rethinking of our understanding of how stars and galaxies form -- is where you have to know some background.

When heated or otherwise energized, each element emits a characteristic fingerprint of frequencies of light known as its emission spectrum.  The fact that these specific frequencies and no others are emitted was key to the development of quantum theory; energy levels in atoms are quantized, or exist in discrete steps, and an atom can no more emit a different frequency of light than you could go down a step-and-three-quarters on your staircase.  Because of these spectral fingerprints, it's now possible to determine the composition of distant stars by looking for the characteristic spectral lines of common elements in the star's spectrum.  This is how Helton et al. figured out that JADES contains large amounts of oxygen.

The emission spectrum of oxygen [Image is in the Public Domain]

Thing is, it shouldn't.  We have lots of oxygen here on Earth because the primordial cloud from which the Solar System condensed had a bunch of it; so, in fact, does the Sun, since it formed from the same cloud.  Alien astronomers could look at the Sun through their telescopes and figure that out the same way that we do.  But oxygen, it turns out, doesn't form all that readily.  The Solar System is oxygen-enriched because the Sun is (at least) a third-generation star.  In the very early universe, when there was nothing much around but hydrogen, helium, and trace amounts of lithium -- the atoms that were formed during the Big Bang itself -- stars had vanishingly small "metal content."  (To astrophysicists, "metals" are any elements heavier than helium.)  As those first stars underwent fusion in their cores, hydrogen was converted to helium, then helium to lithium and carbon; at the end of their lives, those stars that were heavy enough went supernova, and the pressures and temperatures of those colossal explosions not only generated "metals" but distributed them back into space.

Second-generation stars formed from the debris left behind by the explosion of first-generation stars.  Those second-generation stars, during the course of their lives and deaths, would have produced more "metals," and the cycle repeated, ultimately leading to the richness of composition we see in our own Solar System.

But it takes a while.  The amount of oxygen even in early third-generation stars is pretty small.  So where did all the oxygen in an extremely early galaxy like JADES come from?

We don't know.  "It's a very complicated cycle to get as much oxygen as this galaxy has," said study senior author George Rieke.  "So, it is genuinely mind boggling."

So there's evidently something about star formation and galaxy evolution we're missing.  Stars forming only three hundred million years after the Big Bang should be just about entirely hydrogen and helium.  And chances are, JADES is almost certainly not the only anomalous early object.  "The fact that we found this galaxy in a tiny region of the sky means that there should be more of these out there," Helton said. "If we looked at the whole sky, which we can't do with JWST, we would eventually find more of these extreme objects."

For me, it's lovely to look up into the sky on a clear night, but my enjoyment is much enhanced by the fact that I know a little bit about what I'm looking at.  The stars are stellar forges, creating all the matter around us -- we are truly, as Carl Sagan famously said, "made of star stuff."

In short: science itself is beautiful.  Understanding how the world works should do nothing but increase our sense of wonder.  If scientific inquiry isn't accompanied by a sense of "Wow, this is amazing!", you're doing it wrong.  I'll end with a quote from Nobel Prize winning physicist Richard Feynman, who in his 1988 book What Do You Care What Other People Think? had the following to say:

I have a friend who's an artist, and he sometimes takes a view which I don't agree with.  He'll hold up a flower and say, "Look how beautiful it is," and I'll agree.  But then he'll say, "I, as an artist, can see how beautiful a flower is.  But you, as a scientist, take it all apart and it becomes dull."  I think he's kind of nutty. …  There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower.  It only adds.  I don't understand how it subtracts.

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The air that I breathe

A month ago I looked at a geological oddity called banded iron formations -- alternating gray and red bands of iron-rich sediments that have been found all around the world, and all seem to date from about the same time (2.4 billion years ago).  These sedimentary deposits are thought to be the fingerprint of the Great Oxidation Event, when photosynthetic organisms began to pump so much molecular oxygen into the atmosphere that it literally changed the chemistry of the entire planet.

To understand how this happened will take a little bit of explaining.

Photosynthesizers such as plants, phytoplankton, and cyanobacteria evolved a trick for harvesting energy and storing it for use later.  Prior to this, all organisms were heterotrophs -- they required pre-formed organic compounds, which (fortunately for them) were abundant in the early oceans, created by the reducing atmosphere (reduced is chemist-speak for "capable of donating electrons") and sources of energy like lightning and ultraviolet light.  Heterotrophy back then was a fairly inefficient process.  The kind of energy processing they did only produced two ATP molecules, the energy currency of all cells, for every molecule of glucose metabolized.  (Glucose is the most commonly used energy containing molecule.)

Then, around 2.4 billion years ago a new metabolic pathway evolved that could produce ATP directly, driven by the energy in sunlight, rather than by breaking down pre-existing organic molecules.

This process, which probably was created by mutations in a chemosynthesis pathway of the kind we still see today in hydrothermal vent bacteria, used light-capturing pigments like chlorophyll to initiate a chain reaction called photophosphorylation to create ATP by the boatloads.  It required a source of electrons -- nearly all of the energy transfer in cells relies on the movement of electrons in what are called oxidation/reduction reactions -- and the cells performing photophosphorylation found it in abundance.

Water.

The problem was, pulling the electrons from water molecules makes them fall apart.  The result is a pair of hydrogen ions, which can be used for other chemical reactions in the cell -- and free oxygen, which is given off as a waste product.

This led to a huge problem for the rest of life on Earth, because to put not too fine a point on it, oxygen is really freakin' dangerous.  It is, unsurprisingly given the name, a strong oxidizer -- it's really good at pulling electrons away from other substances, which makes them fall apart.  This had the effect of stopping the natural production of food molecules in the ocean; with oxygen in the atmosphere and dissolved in the water, organic compounds now fell to pieces as soon as they were produced.

The result was that in the flip from a reducing atmosphere to an oxidizing atmosphere, nearly all life on Earth died.

The only survivors were:

1. The photosynthesizers -- i.e., the ones who caused the problem in the first place.  They were able to make their own food, so they didn't give a damn if everyone else starved.
2. A handful of anaerobic heterotrophs who were able to escape the oxygen.  We still have them today -- they live in places like anaerobic mud at the bottom of lakes and ponds.
3. A small number of cells that had a pathway to detoxify oxygen.  This pathway involved essentially reversing photosynthesis, combining oxygen with hydrogen ions to lock it up harmlessly as water.  A side benefit -- which ultimately became its major benefit -- is that this is a powerful energy-releasing pathway, and once you can hitch it to ATP production, it's capable of producing 36 ATP molecules per glucose instead of 2, increasing the efficiency of energy capture by a factor of eighteen.  It has to be done in steps -- oxidizing molecules all at once is called "combustion" -- but if it can be slowed down and harnessed, it's a fantastic way of processing energy.  This stepwise oxidation, called the electron transport chain, was such a tremendous advantage that this group -- the aerobic heterotrophs -- basically went out and took over the entire planet.  In fact, they're our ancestors and the ancestors of all the other life forms on Earth that are dependent on oxygen.

The reason all this comes up is a recent discovery I was alerted to by a friend and loyal reader of Skeptophilia.  Researchers analyzing sedimentary rocks from Australia and Canada found fossils of single-celled organisms dating to 1.75 billion years ago that contain traces of thylakoids -- the layered membranes inside chloroplasts on the surfaces of which the oxygen-releasing photophosphorylation reactions take place.  So what we have here are fossils so finely preserved that they retain details not only of cells, nor the organelles inside cells, but the structures inside organelles inside cells.

And not just any old structures.  These, or ones very like them, are the same things that caused all the havoc during the Great Oxidation Event.

Emmanuelle Javaux, of the Université de Liège, who led the study, said, "Their production of oxygen led to accumulation of oxygen and profoundly modified the chemistry of the Earth’s oceans and atmosphere, and the evolution of the biosphere, including complex life."

It's astonishing that traces of these delicate organelles could last in the fossil record for 1.75 billion years.  It gives us a lens into an Earth we wouldn't even recognize, a time when there was nothing whatsoever living on the land, the most complex life was composed of simple clusters of cells, and the oceans were a rapidly-thinning soup of organic monomers.  In a very real sense these microscopic structures created the Earth we see around us today.  Without these tiny pancake-like membranes, the Earth would be a very different place -- one we would not find survivable.

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The story of the bands

Something that strikes me about many scientific discoveries is how they so often come from someone noticing something the rest of us had overlooked or thought insignificant -- and afterward, most importantly, the person asking, "Why?"

A now-familiar example of this is the discovery by the father-and-son team of Luis and Walter Alvarez of the thin iridium-bearing clay layer at the boundary between Cretaceous rocks and Paleocene rocks -- analysis of which led to the discovery of the dinosaur-killing Chicxulub Meteorite Impact.  Without their questioning why there was a narrow layer of heavy-metal-enriched clay at the boundary, everywhere on Earth where there are rocks of that age, we might never have found out about one of the major events in the history of life on Earth.

Another example, less well known, has to do with the banded iron formations found in locations all over the world, including Australia, Brazil, Canada, India, Russia, South Africa, Ukraine, and the United States.  They're striking in appearance, sometimes hundreds of meters thick, with alternating layers of light-colored iron-poor and dark, reddish-brown iron-rich chert or limestone.  Here's an example from near Fortescue Falls in Western Australia:

[Image licensed under the Creative Commons Graeme Churchard from Bristol, UK, Banded iron formation Dales Gorge, CC BY 2.0]

Most of us, I think, would say "pretty rock formation" and leave it at that; a smaller number would recognize the fact that they were sedimentary, and wonder why the colors alternate.  Geologist Preston Cloud, though, took it several large steps farther -- and what he came up with is a little mind-blowing.

What first struck Cloud as curious about banded iron formations is that they're all about the same age.  Regardless of whether they're in Australia or Ontario, just about every banded iron formation studied was deposited around 2.4 billion years ago.  But what could create this pattern not just in one location, but in widely-scattered spots all over the planet?  Whatever the process was must have happened everywhere simultaneously -- and rapidly.

Cloud's hypothesis, which is now well-accepted, is that banded iron formations represent the fingerprint of something called the Great Oxidation Event.  Here's basically what we think happened.

Early living things were largely scavengers, living from abiotically-produced organic compounds dissolved in seawater (and the decomposing bits of dead cells).  These compounds were abundant -- an anoxic atmosphere, rich in reducing compounds like ammonia, methane, and carbon monoxide, together with an energy source like ultraviolet light, generates organic compounds of all sorts.  (As the Miller-Urey experiment conclusively demonstrated.)

But there's always competition between species, and sometimes mutations can create proteins or structures that allow organisms to able to access resources faster or more efficiently than their neighbors.  And that's what happened when a single-celled bacteria evolved a gene to produce chlorophyll, which can quickly capture energy from visible light and store it as chemical energy.

In other words: photosynthesis.

This had only one downside, but it was a huge one.  Photosynthesis generates molecular oxygen.  Oxygen is highly reactive, a strong oxidizer (thus the name), and tears apart organic compounds as quickly as they form.  The presence of oxygen, first dissolved in seawater and then liberated into the atmosphere, did three things.

First, it shut off the abiotic production of excess organic compounds, eliminating the food source for most of life on Earth.

Second, it was directly toxic to most cells, except for the (very) few which had detoxifying enzymes like superoxide dismutase to cope with living in an oxygenated environment -- or which were capable of metabolizing it, using a pathway we now call aerobic respiration and which we have become completely dependent upon.  (It's amazing to think about, but our energy-production system originally evolved as a way to mitigate the poisonous effects of molecular oxygen.)

Third, the oxygen reacted with dissolved ferrous (II) ions in seawater, and altered them to mostly-insoluble ferric (III) ions, which settled out on the ocean floor.  This process, however, bound up the available oxygen, so the reaction dropped oxygen levels, and for a while any iron eroded into the oceans was dissolved as ferrous ions again.  But eventually the photosynthesizing bacteria pumped out enough oxygen that the iron precipitated once more.  The result: alternating layers of iron-poor chert when the oxygen levels were low, and iron-rich chert when the oxygen levels rose.

Eventually, of course, the oxygen rose and stayed high.  By this time, damn near all life on Earth had died; the only ones left were anaerobes that could hide (like the bacteria we still have in deep-sea mud and other anaerobic habitats), and aerobes like our own ancestors that had metabolic pathways to cope with the presence of oxygen.

And the alternating pattern of light and dark layers in banded iron formations chronicle the rising and falling of oxygen during one of the pivotal moments of Earth's prehistory.

Certainly a large part of being a successful scientist is intensive training in a specific field, but I think sometimes there's not enough attention given to another facet of it -- the role of creativity.  The scientists who make important discoveries are usually the ones who notice things the rest of us might just walk past, wonder about them, and most importantly, draw connections between disparate realms to find answers (in this case, geology, chemistry, and biology).  Without this combination of technical knowledge, curiosity, and insight, we would know far less about the universe we live in -- and what an impoverished understanding we would be left with.

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Creepy crawlies

Whenever we have a wet summer -- not an uncommon occurrence in our rainy climate -- we have a plague of little pests trying to get into our house.

They're called millipedes, slinky guys maybe a couple of centimeters long, with lots of legs (not a thousand, though).  They're completely harmless; they don't bite like their cousins the centipedes do, and if you poke at them, they coil up into a ball.  So I guess they're really more of a nuisance than an actual problem.  They don't even damage anything, the way mice can.  Mostly what they seem to do is get in through every crack and crevice (there are lots of these in a big old house like ours), look around for a while, then curl up and die.

[Image licensed under the Creative Commons Totodu74, Anadenobolus monilicornis 03, CC BY-SA 3.0]

So I don't like them, and I wish they stayed outside, but in the grand scheme of things they're no big deal.  Imagine, though, if they were bigger.

A lot bigger.

Just last week, paleontologists announced the discovery on a beach in Northumberland, England, of a millipede fossil from the Carboniferous Period.  It's been dated to the middle of the period, about 326 million years ago.  It looks a bit like the millipedes I see trundling across my basement floor in summer.

Only this one was 2.6 meters long (approximately the length of a Mini Cooper), a half a meter across, and weighed something on the order of fifty kilograms.

It's been named Arthropleura, and holds the record as the largest-known arthropod in Earth's history.  Nothing is known for sure about its behavior; if it's like the rest of millipedes, it was a scavenger on leaf detritus, but there's no way to know for certain.  Given its size, it could well have been a lot more dangerous than the ones we have around now.  To paraphrase the old joke about five-hundred-pound gorillas:

Q:  What does a fifty-kilogram millipede eat?

A:  Anything it wants.

Those of you who are (like me) biology nerds may be frowning in puzzlement at this point.  How on earth could an arthropod get so big?  Their size is limited by the inefficiency of their respiratory system (not to mention the weight of their exoskeletons).  Most arthropods (millipedes included) breathe through pairs of holes called spiracles along the sides of the body.  These holes open into a network of channels called tracheae, which bring oxygen directly to the tissues.  Contrast that with our system; we have a central oxygen-collecting device (lungs), and the hemoglobin in our blood acts as a carrier to bring that oxygen to the tissues.  It's a lot more efficient, which is why the largest mammals are a great deal bigger than the largest arthropods.  (So, no worries that the bad sci-fi movies from the 50s and 60s, with giant cockroaches attacking Detroit, could actually happen.  A ten-meter-long cockroach not only wouldn't be able to oxygenate its own tissues fast enough to survive, it couldn't support its own weight.  It wouldn't eat Detroit, it would just lie there and quietly suffocate.)

So how could there be such ridiculously enormous millipedes?

The answer is as fascinating as the beast itself is.  As the temperature warmed and rainfall increased after the previous period (the Devonian), it facilitated the growth of huge swaths of rain forest across the globe.  In fact, it's the plant material from these rain forests that produced the coal seams that give the Carboniferous its name.  But the photosynthesis of all these plants drove the oxygen levels up -- by some estimates, to around 35% (contrast that to the atmosphere's current 21% oxygen).  This higher oxygen level facilitated the growth of animals who are limited by their ability to uptake it -- i.e., arthropods.  (At the same time, there was a dragonfly species called Meganeura with a seventy-centimeter wingspan.  And unlike millipedes, these things were carnivores, just as modern dragonflies are.)

Eventually, though, the system was unsustainable, and a lot of the rain forests began to die off in the Late Carboniferous, leading to a drier, cooler climate.  However, remember the coal seams -- by that time a huge percentage of the carbon dioxide that had fed the photosynthesis of those rain forests was now locked underground.  The fuse was lit for a catastrophe.

Fast forward to the end of the next period, the Permian, 255 million years ago.  What seems to have happened is a series of colossal volcanic eruptions that created the Siberian Traps, a basalt deposit covering most of what is now Siberia.  The lava ripped through the coal seams, blasting all that stored carbon into the atmosphere as carbon dioxide.  The temperature in the late Permian had been cool and dry, and the spike of carbon dioxide created a commensurate spike in the temperature -- as well as a huge drop in oxygen, used up by the burning coal.  The oxygen concentration seems to have bottomed out at around twelve percent, just over half of what it is now.  The extra carbon dioxide dissolved into ocean water, dropping the pH, and the increasing acidity dissolved away the shells of animals who build them out of calcium carbonate -- e.g. corals and mollusks.

Wide swaths of ocean became anoxic, acidic dead zones.  The anaerobic organisms began to eat through all the dead organic matter, churning out more carbon dioxide and another nasty waste product, sulfur dioxide (which gives the horrible smell to rotten eggs, and is also an acidifier).  The result: an extinction that wiped out an estimated ninety percent of life on Earth.  In short order, a thriving planet had been turned into a hot, dead, foul-smelling wasteland, and it would take millions of years to recover even a fraction of the previous biodiversity.

Of course, at highest risk would be the big guys like our friends Arthropleura and Meganeura, and the Earth hasn't seen giant arthropods like this since then.  Today, the largest arthropod known is the Japanese spider crab (Macrocheira), topping out at around twenty kilograms -- but crabs and other crustaceans have gills and an oxygen carrier called hemocyanin, so they can boost the efficiency of their respiratory system somewhat over their terrestrial cousins.  The largest insect today is the African Goliath beetle (Goliathus), at about a tenth of a kilogram.  And in today's atmosphere, it's at a pretty significant disadvantage.  They may look big and scary, but in reality, they're slow-moving, harmless creatures.  Kind of a beer can with six legs, is how I think of them.

So that's today's look at creepy-crawlies of the past.  In my opinion it's just as well the big ones became extinct.  The last thing I need is having to shoo a fifty-kilogram millipede out of my basement.

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Neil deGrasse Tyson has become deservedly famous for his efforts to bring the latest findings of astronomers and astrophysicists to laypeople.  Not only has he given hundreds of public talks on everything from the Big Bang to UFOs, a couple of years ago he launched (and hosted) an updated reboot of Carl Sagan's wildly successful 1980 series Cosmos.

He has also communicated his vision through his writing, and this week's Skeptophilia book-of-the-week is his 2019 Letters From an Astrophysicist.  A public figure like Tyson gets inundated with correspondence, and Tyson's drive to teach and inspire has impelled him to answer many of them personally (however arduous it may seem to those of us who struggle to keep up with a dozen emails!).  In Letters, he has selected 101 of his most intriguing pieces of correspondence, along with his answers to each -- in the process creating a book that is a testimony to his intelligence, his sense of humor, his passion as a scientist, and his commitment to inquiry.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Deep life, oxygen, and false positives

In the last couple of days we connoisseurs of all things extraterrestrial received some good news and some bad news.

Let's start with the bad news first.

One of the ways astronomers have suggested we might detect life on other planets is the presence of oxygen in the atmosphere, which could be detected spectroscopically.  Oxygen is highly reactive -- it is, unsurprisingly, a strong oxidizer -- meaning that it will tend to react chemically with whatever's around and get bound up into a compound of some sort.  Therefore, the logic went, if there's oxygen in the atmosphere, something must be releasing it faster than it's being removed by ordinary chemical reactions.

Ergo, a living thing (probably doing some variation on photosynthesis).

A piece of research published this week in Earth and Space Chemistry called, "Gas Phase Chemistry of Cool Exoplanet Atmospheres: Insight from Laboratory Simulations," written by a team of scientists from seven different research institutions, came to a startling conclusion -- that atmospheric oxygen might not be a signature of life but a result of photochemistry (chemical reactions triggered by sunlight).

What the researchers did was to expose various mixtures of gases thought to be common components of exoplanet atmospheres to a variety of temperatures (from 25 C to 370 C) and light intensities and spectra, and they found that in many conditions, the energy from the heat and light was sufficient to break down oxidized gases (such as carbon dioxide) and release molecular oxygen.

"People used to suggest that oxygen and organics being present together indicates life, but we produced them abiotically in multiple simulations," said Chao He of Johns Hopkins University's department of Earth and Planetary Science.  "This suggests that even the co-presence of commonly accepted biosignatures could be a false positive for life."

Now, this doesn't mean that if oxygen is found in an exoplanet's atmosphere, it is a false positive; it's just that the He et al. research shows that the finding would not be the slam-dunk astronomers thought it was.  Which is unfortunate.  Given that it's likely that most of the planets hosting life do not have life forms advanced enough to communicate across interstellar space, it'd be nice to have a way to find out they're out there without leaving Earth.  And one of the better possibilities for that has just been shown to be unreliable.

News from the Deep Carbon Observatory, a project that is the collective effort of over a thousand geologists, chemists, and biologists, is more encouraging.  Most of us have the idea that life is only possible on the thin skin of the Earth, and that if you go very deep into the Earth's crust conditions become quickly hot enough and pressurized enough that nothing could live.

Well, that's not true.

The DCO released research last week showing that the amount of life in the "deep biosphere" might amount to as much as twenty billion tons, meaning it would outweigh all of humanity put together by a factor of twenty.  The DCO team drilled three miles deep into the seafloor, and investigated the deepest gold and diamond mines ever created, and everywhere they looked, they found life.

Lots of it.

They found life flourishing at a temperature of 122 C -- twenty-two degrees above the boiling point of water.  They found it in pitch darkness, where there's nothing around to eat except for rocks.  They found it at crushing pressures in the deepest trenches in the ocean.

Sounds like we might have to redefine what we mean by "conditions hospitable for life."

And, germane to the topic of today's post, it will broaden what conditions lie in the "Goldilocks Zone" -- the region surrounding a star where its planets would experience temperatures that are neither too warm nor too cold, but "just right."  Apparently "just right" has a broader range than we ever dreamed, which means that a great many more planets out there might host life than we ever expected.

However, it bears mention that the denizens of the deep biosphere are all simple.  Nothing much more complex than a nematode (roundworm) has been found down there.  So if you were hoping for running across the Morlocks, so far that's a no.

But it's a pretty exciting finding nonetheless, and supports a contention I've had for years -- that life is common in the universe.  Or, as Ellie Arroway put it in Contact, "If not, it'd be an awful waste of space."  Now it's on the chemists and atmospheric scientists to find us a better way to tell that it's there, since the oxygen idea just got shot down.

We'll see what they come up with.  Because I'm certain that it's only a matter of time before we prove beyond any doubt that we're not alone in the universe.

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This week's Skeptophilia book recommendation is Michio Kaku's The Physics of the Impossible.  Kaku takes a look at the science and technology that is usually considered to be in the realm of science fiction -- things like invisibility cloaks, replicators, matter transporters, faster-than-light travel, medical devices like Star Trek's "tricorders" -- and considers whether they're possible given what we know of scientific law, and if so, what it would take to develop them.  In his signature lucid, humorous style, Kaku differentiates between what's merely a matter of figuring out the technology (such as invisibility) and what's probably impossible in a a real and final sense (such as, sadly, faster-than-light travel).  It's a wonderful excursion into the power of the human imagination -- and the power to make at least some of it happen.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

All I need is the air that I breathe

I think my most common thought, while reading a lot of woo-woo writing, is "Learn some damn science before you pretend you know what you're talking about."

Okay, I know that sounds pretty arrogant of me, as if I always know what I'm talking about.  I don't; I make mistakes as often as the next guy.  But one thing I do try to do is research what I'm writing about, find out what science and experimentation have shown, before I launch off into thin air.

I use the "thin air" metaphor deliberately because of a website discovered by a student of mine, a frequent Skeptophilia contributor with a sharp eye for searching out nonsense.  And this time, she found a doozy.  The title of this website, "CO2 and Oxygen in Evolution of Air on Earth and Health," by itself caused some puzzled eyebrow-raising, but nothing like the actual content -- because its author, Artour Rakhimov, seems to be in serious need of basic training in human physiology.

The gist of this website is that all of the medical problems you've ever experienced were caused by having too much oxygen, and too little carbon dioxide, in your tissues.  Yes, you read that right.  Furthermore, we "hyperoxygenate" during times of high activity because we evolved during a time when there was less oxygen in the air, and we had to breathe harder.  Now, hyperventilation is killing us:

Appearance of the first vertebrates (about 550 millions years ago) and the development of prototypes of human lungs took place when air was made up of only about 1% O2, while having much higher percentage of CO2 (Maina, 1998), likely over 7%. Normal air today has many times more O2  (about 20%) and only a fraction of the CO2 (0.03%). However, our cells now still live in the air that existed hundred millions years ago: “But the cells of animals and humans need about 7 % CO2 and only 2% O2 in the surrounding environment. This is the way how our cells live: cells of the heart, brain, and kidneys” (Buteyko, 1977).

Yup.  We still live in "hundred million year old air."  That's why my knees hurt and I have sinus problems.

Anyhow, there we were, millions of years ago, happily consuming our "main nutrient" -- yes, this is what he calls carbon dioxide -- when along came plants to mess everything up:

However, the main parameter of our environment, our air, had dramatic change during later stages of our evolution due to advance of green life that transforms CO2 into O2 during photosynthesis.  We can see that air had dramatic change during evolution. It now has too much oxygen and almost no CO2. Hence, the chief parameter of our environment (we can survive for days or weeks with no water or food, but only for minutes with no air) became abnormal in its composition. It is only existence of our lungs that protected us from extinction. Nature could not anticipate this cardinal change in air, but it did provide us with the means for survival.

No, apparently he doesn't know that photosynthesis predated aerobic respiration as an evolved metabolic pathway.  How exactly our ancestors could have evolved to use oxygen before there were photosynthesizing organisms there to produce oxygen, I have no idea.  Nor do I know how they survived.  I have this strangely amusing image of dinosaurs crashing about in a completely plant-free ecosystem, gasping for breath, and cursing the fact that they'd appeared too soon.

In any case, now that we've established what the problem is, what do we do?   Well, Artour Rakhimov has the solution -- learn to breathe more slowly, or use a "Frolov Breathing Device" -- a thing that basically gets you rebreathing exhaled air.  Oh, and by the way, Rakhimov is selling "Frolov Breathing Devices."  Did I even need to mention that?

Could there be any truth to this?  The answer is "no."  Raising carbon dioxide levels in your blood is called "respiratory acidosis" (carbon dioxide in solution in your blood plasma creates a weak acid, carbonic acid, dropping the blood pH).  This, in turn, is the signal to your brainstem to speed up your breathing rate.  Put simply: carbon dioxide levels, via their effects on your blood pH, are how your body keeps track of how fast you need to breathe.  Slowing down your breathing, or rebreathing exhaled air, will just make you feel uncomfortable, and stimulate the unpleasant sensation that you need to breathe faster.

Don't believe me?  Check out sources here and here -- the latter source stating that humans start showing signs of hypercapnia (carbon dioxide toxicity) at an inhaled air concentration of 3%, and that at 7% -- the level recommended as healthy by Artour Rakhimov -- you will experience "labored breathing, headaches, tinnitus, as well as impaired vision... You are likely to become confused in a few minutes, followed by unconsciousness."

Rakhimov himself seems pretty confused on the topic.  Maybe he's been breathing too much carbon dioxide.

See why I yelled at my computer several times while reading all of this?  Of course, Rakhimov couldn't hear me, and it wasn't because of the tinnitus.  But still, I find the whole thing immensely frustrating, especially given the fact that this is hardly the only idiotic pseudo-medical idea out there -- in fact, I've got another one planned for Monday, to the effect that the problem isn't the air, it's the water.

It's got too little hydrogen in it.  Two hydrogens to one oxygen just isn't enough.

I can barely wait.