Start here

Carbon dating


“At an archaeological dig, a piece of wooden tool is unearthed – and the archaeologist finds it to be 5,000 years old. A child mummy is found high in the Andes – and the archaeologist says the child lived more than 2,000 years ago. How do scientists know how old an object or human remains are? What methods do they use and how do these methods work?

Carbon-14 dating is a way of determining the age of archaeological artifacts of a biological origin up to about 50,000 years old. It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities.”

  • How Stuff Works, How Carbon-14 Dating Works, Marshall Brain

“The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists. Libby received the Nobel Prize in Chemistry for his work in 1960. ” – Wikipedia

How does it work?

Radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.

matthew2262 Radiocarbon dating

From the matthew2262 wordpress blog.

The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide.

That is incorporated into plants by photosynthesis.

Animals then acquire 14 C by eating the plants.

When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14 C it contains begins to decrease, as the 14
C undergoes radioactive decay.

Measuring the amount of 14 C in a sample from a dead plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died.

The older a sample is, the less 14 C there is to be detected, and because the half-life of 14 C (the period of time after which half of a given sample will have decayed) is about 5,730 years.

The oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.

– Carbon Dating, Wikipedia


As years go by, how much C14 is left?

carbon dating part 1

C12 does not decay and remains constant in a sample, whereas C14 decays at an even, constant rate.

By measuring the ratio of C12 to C14, we can understand how long a sample has been around for.

The half life of C 14 is around 5,730 years. As seen by the second graph, this means that if a sample has half of the C14 it should usually have, it has been around for 5,730 years. A quarter of the amount, double that time, one eight of the original amount, more still.

Carbon dating is only as accurate as the consistency of it’s decay rate, which is unchanging and extremely uniform.

It is almost exclusively used for organic material as all life on earth is carbon based.

There is a misconception that carbon dating is used to date the age of the earth. For longer time scales, other elements are used, based on the same principles.

Graphs from a video by Scientific American that explains carbon dating. Watch the full video here How Does Radiocarbon Dating Work? – Instant Egghead #28: Scientific American

  • text from http://blunt-science.tumblr.com/post/109954909373/a-representation-of-the-age-span-carbon-dating-is


Is radiocarbon dating reliable?

Excerpted from National Center for Science Education, by Christopher Gregory Weber:


Radiocarbon dating can easily establish that humans have been on the earth for over twenty thousand years …. it is one of the most reliable of all the radiometric dating methods.

Question: How does carbon-14 dating work?

carbon dating part 1

Cosmic rays in the upper atmosphere are constantly converting the isotope nitrogen-14 (N-14) into carbon-14 (C-14 or radiocarbon).

Living organisms are constantly incorporating this C-14 into their bodies along with other carbon isotopes.

When the organisms die, they stop incorporating new C-14

The old C-14 starts to decay back into N-14 by emitting beta particles.

The older an organism’s remains are, the less beta radiation it emits because its C-14 is steadily dwindling at a predictable rate.

So, if we measure the rate of beta decay in an organic sample, we can calculate how old the sample is. C-14 decays with a half-life of 5,730 years.


Question: Kieth and Anderson radiocarbon-dated the shell of a living freshwater mussel and obtained an age of over two thousand years. ICR creationists claim that this discredits C-14 dating. How do you reply?

Answer: It does discredit the C-14 dating of freshwater mussels, but that’s about all. Kieth and Anderson show considerable evidence that the mussels acquired much of their carbon from the limestone of the waters they lived in and from some very old humus as well.

Carbon from these sources is very low in C-14 because these sources are so old and have not been mixed with fresh carbon from the air. Thus, a freshly killed mussel has far less C-14 than a freshly killed something else, which is why the C-14 dating method makes freshwater mussels seem older than they really are.

When dating wood there is no such problem because wood gets its carbon straight from the air, complete with a full dose of C-14.


Question: A sample that is more than fifty thousand years old shouldn’t have any measurable C-14. Coal, oil, and natural gas are supposed to be millions of years old; yet creationists say that some of them contain measurable amounts of C-14, enough to give them C-14 ages in the tens of thousands of years. How do you explain this?

Answer: Very simply. Radiocarbon dating doesn’t work well on objects much older than twenty thousand years, because such objects have so little C-14 left that their beta radiation is swamped out by the background radiation of cosmic rays and potassium-40 (K-40) decay.


Younger objects can easily be dated, because they still emit plenty of beta radiation, enough to be measured after the background radiation has been subtracted out of the total beta radiation. However, in either case, the background beta radiation has to be compensated for, and, in the older objects, the amount of C-14 they have left is less than the margin of error in measuring background radiation. As Hurley points out:

Without rather special developmental work, it is not generally practicable to measure ages in excess of about twenty thousand years, because the radioactivity of the carbon becomes so slight that it is difficult to get an accurate measurement above background radiation. (p. 108)

Cosmic rays form beta radiation all the time; this is the radiation that turns N-14 to C-14 in the first place. K-40 decay also forms plenty of beta radiation. Stearns, Carroll, and Clark point out that “. . . this isotope [K-40] accounts for a large part of the normal background radiation that can be detected on the earth’s surface” (p. 84).

This radiation cannot be totally eliminated from the laboratory, so one could probably get a “radiocarbon” date of fifty thousand years from a pure carbon-free piece of tin. However, you now know why this fact doesn’t at all invalidate radiocarbon dates of objects younger than twenty thousand years and is certainly no evidence for the notion that coals and oils might be no older than fifty thousand years.


Question: Creationists such as Cook (1966) claim that cosmic radiation is now forming C-14 in the atmosphere about one and one-third times faster than it is decaying. If we extrapolate backwards in time with the proper equations, we find that the earlier the historical period, the less C-14 the atmosphere had.

If we extrapolate as far back as ten thousand years ago, we find the atmosphere would not have had any C-14 in it at all. If they are right, this means all C-14 ages greater than two or three thousand years need to be lowered drastically and that the earth can be no older than ten thousand years. How do you reply?

Answer: Yes, Cook is right that C-14 is forming today faster than it’s decaying. However, the amount of C-14 has not been rising steadily as Cook maintains; instead, it has fluctuated up and down over the past ten thousand years. How do we know this? From radiocarbon dates taken from bristlecone pines. There are two ways of dating wood from bristlecone pines: one can count rings or one can radiocarbon-date the wood.

Since the tree ring counts have reliably dated some specimens of wood all the way back to 6200 BC, one can check out the C-14 dates against the tree-ring-count dates. Admittedly, this old wood comes from trees that have been dead for hundreds of years, but you don’t have to have an 8,200-year-old bristlecone pine tree alive today to validly determine that sort of date. It is easy to correlate the inner rings of a younger living tree with the outer rings of an older dead tree. The correlation is possible because, in the Southwest region of the United States, the widths of tree rings vary from year to year with the rainfall, and trees all over the Southwest have the same pattern of variations.

When experts compare the tree-ring dates with the C-14 dates, they find that radiocarbon ages before 1000 BC are really too young—not too old as Cook maintains. For example, pieces of wood that date at about 6200 BC by tree-ring counts date at only 5400 BC by regular C-14 dating and 3900 BC by Cook’s creationist revision of C-14 dating (as we see in the article, “Dating, Relative and Absolute,” in the Encyclopaedia Britannica). So, despite claims, C-14 before three thousand years ago was decaying faster than it was being formed and C-14 dating errs on the side of making objects from before 1000 BC look too young, not too old.


Question: But don’t trees sometimes produce more than one growth ring per year? Wouldn’t that spoil the tree-ring count?

Answer: If anything, the tree-ring sequence suffers far more from missing rings than from double rings. This means that the tree-ring dates would be slightly too young, not too old.

Of course, some species of tree tend to produce two or more growth rings per year. But other species produce scarcely any extra rings. Most of the tree-ring sequence is based on the bristlecone pine.  This tree rarely produces even a trace of an extra ring; on the contrary, a typical bristlecone pine has up to 5 percent of its rings missing. Concerning the sequence of rings derived from the bristlecone pine,  Ferguson says:

In certain species of conifers, especially those at lower elevations or in southern latitudes, one season’s growth increment may be composed of two or more flushes of growth, each of which may strongly resemble an annual ring.

Such multiple growth rings are extremely rare in bristlecone pines, however, and they are especially infrequent at the elevation and latitude (37� 20′ N) of the sites being studied. In the growth-ring analyses of approximately one thousand trees in the White Mountains, we have, in fact, found no more than three or four occurrences of even incipient multiple growth layers. (p. 840)

In years of severe drought, a bristlecone pine may fail to grow a complete ring all the way around its perimeter; we may find the ring if we bore into the tree from one angle, but not from another. Hence at least some of the missing rings can be found. Even so, the missing rings are a far more serious problem than any double rings.

Other species of trees corroborate the work that Ferguson did with bristlecone pines.  Before his work, the tree-ring sequence of the sequoias had been worked out back to 1250 BC. The archaeological ring sequence had been worked out back to 59 BC. The limber pine sequence had been worked out back to 25 BC.

The radiocarbon dates and tree-ring dates of these other trees agree with those Ferguson got from the bristlecone pine.  But even if he had had no other trees with which to work except the bristlecone pines, that evidence alone would have allowed him to determine the tree-ring chronology back to 6200 BC. …


Question: Does outside archaeological evidence confirm the C-14 dating method?

Answer: Yes. When we know the age of a sample through archaeology or historical sources, the C-14 method (as corrected by bristlecone pines)  agrees with the age within the known margin of error.

For instance, Egyptian artifacts can be dated both historically and by radiocarbon, and the results agree. At first, archaeologists used to complain that the C-14 method must be wrong, because it conflicted with well-established archaeological dates; but, as Renfrew has detailed, the archaeological dates were often based on false assumptions.

One such assumption was that the megalith builders of western Europe learned the idea of megaliths from the Near-Eastern civilizations. As a result, archaeologists believed that the Western megalith-building cultures had to be younger than the Near Eastern civilizations.

Many archaeologists were skeptical when Ferguson’s calibration with bristlecone pines was first published, because, according to his method, radiocarbon dates of the Western megaliths showed them to be much older than their Near-Eastern counterparts.

However, as Renfrew demonstrated, the similarities between these Eastern and Western cultures are so superficial that the megalith builders of western Europe invented the idea of megaliths independently of the Near East. So, in the end, external evidence reconciles with and often confirms even controversial C-14 dates.

One of the most striking examples of different dating methods confirming each other is Stonehenge. C-14 dates show that Stonehenge was gradually built over the period from 1900 BC to 1500 BC, long before the Druids, who claimed Stonehenge as their creation, came to England.

Astronomer Gerald S. Hawkins calculated with a computer what the heavens were like back in the second millennium BC, accounting for the precession of the equinoxes, and found that Stonehenge had many significant alignments with various extreme positions of the sun and moon (for example, the hellstone marked the point where the sun rose on the first day of summer). Stonehenge fits the heavens as they were almost four thousand years ago, not as they are today, thereby cross-verifying the C-14 dates.


Relative Ages of Rocks: WIkiBooks

(WikiBooks: A project hosted by the Wikimedia Foundation for the creation of free content textbooks)



External links

Willard Libby and Radiocarbon Dating. American Chemical Society

Learning Standards

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012), from the National Research Council of the National Academies.

By the end of grade 12. Radioactive decay lifetimes and isotopic content in rocks provide a way of dating rock formations and thereby fixing the scale of geological time.

College Board Standards for College Success: Science

ES.3 Earth’s History: Relative and Absolute dating. Students understand that various dating methods — relative and absolute — have been used to determine the age of Earth.

Suggested Connections. Between Earth Science and Other Disciplines: Evidence of Common Ancestry and Divergence (LS.1.1); Living Systems and the Physical Environment (LS.3.1); Nuclear Chemistry (C.1.6); Nuclear Interactions and the Conservation of Mass–Energy (P.2.3)

Benchmarks: American Association for the Advancement of Science.

Knowledge of radioactivity helps them understand how rocks can be dated, which helps them appreciate the scale of geologic time… Scientific evidence indicates that some rock layers are several billion years old. 4C/H6** (BSL)


Peptide bonds – How we make proteins

2 amino acids can join to form a peptide.

A very long peptide is known as a protein.

When they join one of the amino acid’s loses an H atom, while the other loses an OH moiety (part of a molecule)  They join together to form H2O (water.) This is a condensation reaction.

peptide bond formation 1

Doc Kaiser’s Microbiology Home Page (Gary E. Kaiser)


Here is another animation of the same process

The CONH link created is called a peptide bond (red)
Water (blue) is removed.

This process can be continued repeatedly to form longer peptides (eventually, when they are over 50 amino acids long, we call them proteins.)

peptide bond formation 2

BioTopics.co.uk by Richard Steane

The monomer here is an amino acid.

The polymer here is a peptide or protein.

These are 20 different types of common amino acids.

Amino acids are bonded together to make peptides, or proteins.

A peptide is just a small protein, less than 50 amino acids (aa) long.

Proteins are much larger, 100 aa, 500 aa, even 1,000 aa.

A chain of amino acids folds up into a shape.

Every protein has its own shape.


If all land ice melted how would coastlines change

Scientists have used evidence to reconstruct sea-level rise around America’s northeast coast over the last 10,000 years.

New Jersey going back 10,000 years in research newly published in the Journal of Quaternary Science. To do this, they collected sediment cores drilled tens of meters below ground from coastal marshes, then examined the sediment back in a lab for microscopic organisms that only exist at specific depths below sea level. Salt marsh grasses also fossilized within the sediment were used to radiocarbon-date the samples.

The 10 maps contained in the GIF below show the movement of sea level at 1,000-year intervals leading up today:


sea rise GIF Influence of tidal-range change and sediment compaction on Holocene relative sea-level change in New Jersey,

HORTON, B. P., ENGELHART, S. E., HILL, D. F., KEMP, A. C., NIKITINA, D., MILLER, K. G. and PELTIER, W. R. (2013), Influence of tidal-range change and sediment compaction on Holocene relative sea-level change in New Jersey, USA. J. Quaternary Sci., 28: 403–411

If This GIF of 10,000 Years of Sea Level Rise Doesn’t Freak You Out, Nothing Wil


Boston underwater: How the rising sea levels will affect the city


What Could Disappear. New York Times Sunday Review.


“If we keep burning fossil fuels indefinitely, global warming will eventually melt all the ice at the poles and on mountaintops, raising sea level by 216 feet. Explore what the world’s new coastlines would look like.

“The maps here show the world as it is now, with only one difference: All the ice on land has melted and drained into the sea, raising it 216 feet and creating new shorelines for our continents and inland seas.

There are more than five million cubic miles of ice on Earth, and some scientists say it would take more than 5,000 years to melt it all. If we continue adding carbon to the atmosphere, we’ll very likely create an ice-free planet, with an average temperature of perhaps 80 degrees Fahrenheit instead of the current 58.”

from National Geographic Magazine, What the World Would Look Like if All the Ice Melted

Map 1

The entire Atlantic seaboard would vanish, along with Florida and the Gulf Coast. In California, San Francisco’s hills would become a cluster of islands and the Central Valley a giant bay. The Gulf of California would stretch north past the latitude of San Diego—not that there’d be a San Diego.

Ice melt north america

Map 2

The Amazon Basin in the north and the Paraguay River Basin in the south would become Atlantic inlets, wiping out Buenos Aires, coastal Uruguay, and most of Paraguay. Mountainous stretches would survive along the Caribbean coast and in Central America.

Ice melt South America

Map 3

London? A memory. Venice? Reclaimed by the Adriatic Sea. Thousands of years from now, in this catastrophic scenario, the Netherlands will have long since surrendered to the sea, and most of Denmark will be gone too. Meanwhile, the Mediterranean’s expanding waters will also have swelled the Black and Caspian Seas.

Ice melt Europe

Map 3

Land now inhabited by 600 million Chinese would flood, as would all of Bangladesh, population 160 million, and much of coastal India. The inundation of the Mekong Delta would leave Cambodia’s Cardamom Mountains stranded as an island.

Ice melt Asia


East Antarctica: The East Antarctica ice sheet is so large—it contains four-fifths of all the ice on Earth—that it might seem unmeltable. It survived earlier warm periods intact. Lately it seems to be thickening slightly—because of global warming. The warmer atmosphere holds more water vapor, which falls as snow on East Antarctica. But even this behemoth is unlikely to survive a return to an Eocene Climate.

West Antarctica: Like the Greenland ice sheet, the West Antarctic one was apparently much smaller during earlier warm periods. It’s vulnerable because most of it sits on bedrock that’s below sea level.The warming ocean is melting the floating ice sheet itself from below, causing it to collapse. Since 1992 it has averaged a net loss of 65 million metric tons of ice a year.

Ice melt Antarctica

All maps by: Jason Treat, Matthew Twombly, Web Barr, Maggie Smith, NGM Staff. Art Kees Veenebos. From Sept. 2013 National Geographic Society

What the World Would Look Like if All the Ice Melted (National Geographic)


Learning Standards


Antarctic mantle plume

Let’s All Calm Down and Make Sense of That Antarctic Mantle Plume

Ryan F. Mandelbaum, Gizmodo, 11/8/2017

Three decades ago, scientists began to study the possibility that there was a plume of hot rock coming up from the mantle, heating parts of Western Antarctica. Back in September, researchers published results of a model showing how such a plume might affect the Antarctic ice sheet. Today, these headlines started to appear:

antarctic plume headlines

And my brain felt like it started to leak out of my ears. So we’re going to present to you what actually happened, what we know about the plume, and why you shouldn’t worry about “something monstrous.”

It’s definitely a neat idea from a scientific perspective. “I was interested because my first impression was that it’s surprising,” Hélène Seroussi, scientist at NASA’s Jet Propulsion Laboratory told Gizmodo. “There’s this feature under the ice and we still have ice present there. It was interesting to reconcile these two things that were contradictory in the first place.”

Seroussi and her group then tried to build a model of what would happen if a mantle plume did exist there and see what such a plume’s effects on the ice sheet and heating in the ice might be. This model, aided by observations from a NASA satellite, helped explain the amount of heat such a plume might add. It could even melt several centimeters of ice right above, and explain some of the heat creating Antarctica’s hidden lakes and rivers. The researchers published the model in the Journal of Geophysical Research: Solid Earth.

NSF Zina Deretsky Antarctica

The plume would have been there for around fifty million years, and the ice sheet would have formed atop it. It likely affected the way ice melted at the end of the last Ice Age. But it’s not really something to worry about. “It’s been there forever, it will remain there for a really long time,” said Seroussi. “We don’t have to worry about it. But at the same time, as the future brings more heat… the ice will probably be warmer in this area than in other places.”

The presence and modeling of such heating is important data to have to understand the future of the Antarctic ice sheet. After all, warm ice flows faster than colder ice, like warm honey flows faster than cold honey.

But no one has actually measured a plume. There’s just a new model to help explain a hypothesis. A research associate from the University of Texas, Duncan Young, explained to Gizmodo that the paper “is a valuable use of the advances in ice sheet modeling” integrating the sensitivity of the ice sheet into it. He points out that there’s more up-to-date-data that can be added, including satellite observations. Seroussi also told Gizmodo that more direct observations could help explain what was happening.

So there you have it, dear readers. I was in the midst of reporting this interesting but maybe not so revolutionary paper about a geophysical model and suddenly a bunch of other people saw the press release, didn’t bother to read the paper, then went insane and decided that scientists made a huge discovery. That’s not what happened. But, uh, the model is cool.

[Journal of Geophysical Research: Solid Earth]

Source: https://gizmodo.com/lets-all-calm-down-and-make-sense-of-that-antarctic-man-1820268978


  1. What are the physical layers of the earth?  Make a simple, clear diagram and label it.  Earth’s layered structure
  2. Why is the Earth’s interior hot?
  3. What is the mantle? arth’s layered structure
  4. What is mantle convection?  mantle convection
  5. How are popular news articles covering this story?
  6. Scientists don’t explain this story the same way that the newspapers do: How are scientists explaining this story? (See this blog post)

Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

8.MS-ESS2-1. Use a model to illustrate that energy from Earth’s interior drives convection that cycles Earth’s crust, leading to melting, crystallization, weathering, and deformation
of large rock formations, including generation of ocean sea floor at ridges,
submergence of ocean sea floor at trenches, mountain building, and active volcanic

HS-ESS2-3. Use a model based on evidence of Earth’s interior to describe the cycling of matter due to the outward flow of energy from Earth’s interior and gravitational movement of denser materials toward the interior.

HS-ESS2-4. Use a model to describe how variations in the flow of energy into and out of Earth’s systems over different time scales result in changes in climate. Analyze and interpret data to explain that long-term changes in Earth’s tilt and orbit result in cycles of
climate change such as Ice Ages.

HS-ESS1-5. Evaluate evidence of the past and current movements of continental and oceanic crust, the theory of plate tectonics, and relative densities of oceanic and continental rocks to explain why continental rocks are generally much older than rocks of the ocean floor.


This website is educational. Materials within it are being used in accord with the Fair Use doctrine, as defined by United States law.

§107. Limitations on Exclusive Rights: Fair Use

Notwithstanding the provisions of section 106, the fair use of a copyrighted work, including such use by reproduction in copies or phone records or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use, the factors to be considered shall include:

the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
the nature of the copyrighted work;
the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
the effect of the use upon the potential market for or value of the copyrighted work. (added pub. l 94-553, Title I, 101, Oct 19, 1976, 90 Stat 2546)

Teaching protein translation

Teaching how DNA gets turned into mRNA, and then hooks up to tRNA with amino acids, and forms proteins. It’s not easy for everyone, and especially difficult for many ELL and SPED students. Solution? Make it tactile – use manipulatives. I use a large student table as a cell, and pieces on the table represent organelles and molecules.

I spent a long time finding the right graphics to represent the nucleus, chromosomes, DNA, RNA, mitochondria, and of course the rough ER and Golgi (I always try and reinforce the idea that cells are simultaneously full of many organelles, even if we’re only using a few of them.)

Then I printed them out on heavy stock paper. (I need to laminate it next time, but this was a trial run.) Cut out all the pieces.

The trick is to have many nucleotides, so they can get practice with multiple combinations. Here 27 bases, for 9 codons, making an 8 amino acid peptide (plus one STOP codon.)

Here is the PDF file with the graphics (DNA to mRNA to ribosome to tRNA)

And here is what it looks like on a table top, when students use them.

DNA protein translation manipulative

DNA protein translation manipulative 2

Learning Standards

HS-LS1-1. Construct a model of transcription and translation to explain the roles of DNA and RNA that code for proteins that regulate and carry out essential functions of life.


Michelangelo’s Secret Message in the Sistine Chapel

Michelangelo’s Secret Message in the Sistine Chapel: A Juxtaposition of God and the Human Brain

Scientific American, R. Douglas Fields on May 27, 2010

At the age of 17 he began dissecting corpses from the church graveyard. Between the years 1508 and 1512 he painted the ceiling of the Sistine Chapel in Rome. Michelangelo Buonarroti—known by his first name the world over as the singular artistic genius, sculptor and architect—was also an anatomist, a secret he concealed by destroying almost all of his anatomical sketches and notes. Now, 500 years after he drew them, his hidden anatomical illustrations have been found—painted on the ceiling of the Sistine Chapel, cleverly concealed from the eyes of Pope Julius II and countless religious worshipers, historians, and art lovers for centuries—inside the body of God.

Michelangelo Light Darkness First_Day_of_Creation

This is the conclusion of Ian Suk and Rafael Tamargo, in their paper in the May 2010 issue of the scientific journal Neurosurgery. Suk and Tamargo are experts in neuroanatomy at the Johns Hopkins University School of Medicine in Baltimore, Maryland.

In 1990, physician Frank Meshberger published a paper in the Journal of the American Medical Association deciphering Michelangelo’s imagery with the stunning recognition that the depiction in God Creating Adam in the central panel on the ceiling was a perfect anatomical illustration of the human brain in cross section. Meshberger speculates that Michelangelo surrounded God with a shroud representing the human brain to suggest that God was endowing Adam not only with life, but also with supreme human intelligence.

Now in another panel The Separation of Light from Darkness, Suk and Tamargo have found more. Leading up the center of God’s chest and forming his throat, the researchers have found a precise depiction of the human spinal cord and brain stem.

Michelangelo 1

Is the ceiling of the Sistine Chapel a 500 year-old puzzle that is only now beginning to be solved? What was Michelangelo saying by construction the voice box of God out of the brain stem of man? Is it a sacrilege or homage?

It took Michelangelo four years to complete the ceiling of the Sistine Chapel. He proceeded from east to west, starting from the entrance of the Chapel to finish above the altar. The last panel he painted depicts God separating light from darkness. This is where the researchers report that Michelangelo hid the human brain stem, eyes and optic nerve of man inside the figure of God directly above the altar.

Art critics and historians have long puzzled over the odd anatomical irregularities in Michelangelo’s depiction of God’s neck in this panel, and by the discordant lighting in the region. The figures in the fresco are illuminated diagonally from the lower left, but God’s neck, highlighted as if in a spotlight, is illuminated straight-on and slightly from the right.

Michelangelo 2

How does one reconcile such clumsiness by the world’s master of human anatomy and skilled portrayer of light with bungling the image of God above the altar? Suk and Tamargo propose that the hideous goiter-disfigured neck of God is not a mistake, but rather a hidden message. They argue that nowhere else in any of the other figures did Michelangelo foul up his anatomically correct rendering of the human neck.

They show that if one superimposes a detail of God’s odd lumpy neck in the Separation of Light and Darkness on a photograph of the human brain as seen from below, the lines of God’s neck trace precisely the features of the human brain [see images at right].

There is something else odd about this picture. A role of fabric extends up the center of God’s robe in a peculiar manner. The clothing is bunched up here as is seen nowhere else, and the fold clashes with what would be the natural drape of fabric over God’s torso. In fact, they observe, it is the human spinal cord, ascending to the brain stem in God’s neck. At God’s waist, the robe twists again in a peculiar crumpled manner, revealing the optic nerves from two eyes, precisely as Leonardo Da Vinci had shown them in his illustration of 1487. Da Vinci and Michelangelo were contemporaries and acquainted with each other’s work.

The mystery is whether these neuroanatomical features are hidden messages or whether the Sistine Chapel a Rorshach tests upon which anyone can extract an image that is meaningful to themselves. The authors of the paper are, after all, neuroanatomists. The neuroanatomy they see on the ceiling may be nothing more than the man on the moon.
But Michelangelo also depicted other anatomical features elsewhere in the ceiling, according to other scholars; notably the kidney, which was familiar to Michelangelo and was of special interest to him as he suffered from kidney stones.

If the hidden figures are intentional, what do they mean? The authors resist speculation, but a great artist does not merely reproduce an object in a work of art, he or she evokes meaning through symbolism. Is Separation of Light from Darkness an artistic comment on the enduring clash between science and religion?

Recall that this was the age when the monk Copernicus was denounced by the Church for theorizing that the Earth revolved around the sun. It was a period of struggle between scientific observation and the authority of the Church, and a time of intense conflict between Protestants and Catholics.

It is no secret that Michelangelo’s relationship with the Catholic Church became strained. The artist was a simple man, but he grew to detest the opulence and corruption of the Church. In two places in the masterpiece, Michelangelo left self portraits—both of them depicting himself in torture. He gave his own face to Saint Bartholomew’s body martyred by being skinned alive, and to the severed head of Holofernes, who was seduced and beheaded by Judith.

Michelangelo was a devout person, but later in life he developed a belief in Spiritualism, for which he was condemned by Pope Paul IV. The fundamental tenet of Spiritualism is that the path to God can be found not exclusively through the Church, but through direct communication with God. Pope Paul IV interpreted Michelangelo’s Last Judgment, painted on the wall of the Sistine Chapel 20 years after completing the ceiling, as defaming the church by suggesting that Jesus and those around him communicated with God directly without need of Church. He suspended Michelangelo’s pension and had fig leaves painted over the nudes in the fresco. According to the artist’s wishes, Michelangelo’s body is not buried on the grounds of the Vatican, but is instead interred in a tomb in Florence.

Perhaps the meaning in the Sistine Chapel is not of God giving intelligence to Adam, but rather that intelligence and observation and the bodily organ that makes them possible lead without the necessity of Church directly to God. The material is rich for speculation and the new findings will doubtlessly spark endless interpretation. We may never know the truth, but in Separation of Light from Darkness, Michelangelo’s masterpiece combines the worlds of art, religion, science, and faith in a provocative and awe inspiring work of art, which may also be a mirror.

Images from “Concealed Neuroanatomy in Michelangelo’s Separation of Light From Darkness in the Sistine Chapel,” by Ian Suk and Rafael J. Tamargo in Neurosurgery, Vol. 66, No. 5, pp. 851-861.

About the author: R. Douglas Fields, Ph.D., is a neuroscientist and an adjunct professor at the University of Maryland, College Park. He is author of Why We Snap, about the neuroscience of sudden aggression, and The Other Brain, about glia. Fields serves on Scientific American Mind’s board of advisers.


Related articles

Separation of Light from Darkness. Article on the painting from Wikipedia.


Origami membrane protein

All cell membranes have proteins embedded in them. Each protein has its own job.

Students may draw them like this:

But a more sophisticated artist could show much more detail.

One could show that proteins are three-dimensional machines, with movable parts.

Creative Biomart Lipidsome-Based-Membrane-Protein-Production

Now instead of a static image, visualize how busy it is near the cell membrane:

Many molecules going in and out of a cell – and not randomly.

Membrane proteins open or close, as needed, to let certain molecules in, and other ones out.

Cell membrane lipid bilayer animation

What we’re going to see today is a student in our class build a three dimensional model of a membrane protein.

He made one monomer; and then attached several of them to make a polymer.

Monomer Polymer Lego analogy

Instead of attaching eight monomers in a straight line, he’ll form them into a circle:

This becomes a model of a protein that floats in a cell’s membrane,

It can have two shapes, closed or opened, depending on how it’s folded.

It allows certain molecules in or out of a cell, as needed.

protein folding 1

protein folding 2

protein folding 3

protein folding 4

protein folding 5

protein folding 6

protein folding 7

For instructions we may refer to a video from AskABiologist:

Proteins are made of building blocks called amino acids, and have their own special shape. Not only do they look different, but they have different jobs to do inside the cell. Some proteins help move things around in the body, others act like support structures or glue to hold parts of the cell together, and some can help reactions in the cell go faster. The protein we’re making is a channel that sits in the outer cell surface, or membrane, and works like a door that lets certain molecules pass through. Some channels are open all the time while others can be closed depending on signals from the cell or the environment.

Narration by Rebecca Elaine Ryan
Original origami design by Florence Temko

Step-by-step directions

Here’s the video from AskABiologist


Learning Standards

Massachusetts Curriculum Frameworks: Biology

8.MS-PS1-1. Develop a model to describe that (a) atoms combine in a multitude of ways to
produce pure substances which make up all of the living and nonliving things that we
encounter, (b) atoms form molecules and compounds that range in size from two to
thousands of atoms, and (c) mixtures are composed of different proportions of pure

Clarification Statement: Examples of molecular-level models could include drawings, three-dimensional ball and stick structures, and computer representations showing different molecules with different types of atoms.

HS-LS1-6. Construct an explanation based on evidence that organic molecules are primarily composed of six elements, where carbon, hydrogen, and oxygen atoms may combine with nitrogen, sulfur, and phosphorus to form monomers that can further combine to form large carbon-based macromolecules.
Clarification Statements:
• Monomers include amino acids, mono- and disaccharides, nucleotides, and fatty acids.
• Organic macromolecules include proteins, carbohydrates (polysaccharides), nucleic acids, and lipids.

Disciplinary Core Idea Progression Matrix: PS1.A Structure of matter: That matter is composed of atoms and molecules can be used to explain the properties of substances, diversity of materials, how mixtures will interact, states of matter, phase changes, and conservation of matter.