Ancient Egyptian Statues
Egyptologists, writers, scholars, and others, have argued the race of the ancient Egyptians since at least the 1970's. Some today believe they were Sub-Saharan Africans. We can see this interpretation portrayed in Michael Jackson's 1991 music video for “Remember the Time" from his "Dangerous" album. The video, a 10-minute mini-film, includes performances by Eddie Murphy and Magic Johnson.
Reactionaries, meanwhile, say that there's never been any significant black civilizations—an utter falsehood, of course. There were several in fact, highly advanced African empires and kingdoms throughout history. Curiously, some extreme Right groups have even used blood group data to proclaim a Nordic origin to King Tutankhamun and his brethren.
The problem, it was thought, is that mummy DNA couldn't be sequenced. But a group of international researchers, using unique methods, have overcome the barriers to do just that. They found that the ancient Egyptians were most closely related to the peoples of the Near East, particularly from the Levant. This is the Eastern Mediterranean which today includes the countries of Turkey, Iraq, Israel, Jordan, Syria, and Lebanon. The mummies used were from the New Kingdom and a later period, (a period later than the Middle Kingdom) when Egypt was under Roman rule.
Egyptian mummy. British Museum. Flikr.
Modern Egyptians share 8% of their genome with central Africans, far more than ancient ones, according to the study, published in the journal Nature Communications. The influx of Sub-Saharan genes only occurred within the last 1,500 years. This could be attributed to the trans-Saharan slave trade or just from regular, long distance trade between the two regions. Improved mobility on the Nile during this period increased trade with the interior, researchers claim.
Egypt over the span of antiquity was conquered many times including by Alexander the Great, by the Greeks, Romans, Arabs, and more. Researchers wanted to know if these constant waves of invaders caused any major genetic changes in the populace over time. Group leader Wolfgang Haak at the Max Planck Institute in Germany said, "The genetics of the Abusir el-Meleq community did not undergo any major shifts during the 1,300 year timespan we studied, suggesting that the population remained genetically relatively unaffected by foreign conquest and rule."
The study was led by archeogeneticist Johannes Krause, also of the Max Planck Institute. Historically, there's been a problem finding intact DNA from ancient Egyptian mummies. "The hot Egyptian climate, the high humidity levels in many tombs and some of the chemicals used in mummification techniques, contribute to DNA degradation and are thought to make the long-term survival of DNA in Egyptian mummies unlikely," Dr. Krause said.
The mummified remains of Queen Hatshepsut wet-nurse Sitre-In. Egyptian Museum, Cairo. 2007. Getty Images.
It was also thought that, even if genetic material were recovered, it may not be reliable. Despite this, Krause and colleagues have been able to introduce robust DNA sequencing and verification techniques, and completed the first successful genomic testing on ancient Egyptian mummies.
Each came from Abusir el-Meleq, an archaeological site situated along the Nile, 70 miles (115 km) south of Cairo. This necropolis there houses mummies which display aspects revealing a dedication to the cult of Osiris, the green-skinned god of the afterlife.
First, the mitochondrial genomes from 90 of mummies were taken. From these, Krause and colleagues found that they could get the entire genomes from just three of the mummies in all. For this study, scientists took teeth, bone, and soft tissue samples. The teeth and bones offered the most DNA. They were protected by the soft tissue which has been preserved through the embalming process.
Researchers took these samples back to a lab in Germany. They began by sterilizing the room. Then they put the samples under UV radiation for an hour to sterilize them. From there, they were able to perform DNA sequencing.
An Egyptian necropolis. Getty Images.
Scientists also gathered data on Egyptian history and archaeological data of northern Africa, to give their discoveries some context. They wanted to know what changes had occurred over time. To find out, they compared the mummies' genomes to that of 100 modern Egyptians and 125 Ethiopians. “For 1,300 years, we see complete genetic continuity," Krause said.
The oldest mummy sequenced was from the New Kingdom, 1,388 BCE, when Egypt was at the height of its power and glory. The youngest was from 426 CE, when the country was ruled from Rome. The ability to acquire genomic data on ancient Egyptians is a dramatic achievement, which opens up new avenues of research.
One limitation according to their report, “all our genetic data were obtained from a single site in Middle Egypt and may not be representative for all of ancient Egypt." In southern Egypt they say, the genetic makeup of the people may have been different, being closer to the interior of the continent.
Researchers in future want to determine exactly when Sub-Saharan African genes seeped into the Egyptian genome and why. They'll also want to know where ancient Egyptians themselves came from. To do so, they'll have to identify older DNA from, as Krause said, “Back further in time, in prehistory."
Using high-throughput DNA sequencing and cutting-edge authentication techniques, researchers proved they could retrieve reliable DNA from mummies, despite the unforgiving climate and damaging embalming techniques.
Further testing will likely contribute much knowledge to our understanding of the ancient Egyptians and perhaps even those from other places as well, helping to fill in the gaps in humanity's collective memory.
To learn about the latest Egyptian archaeological find, click here:
Our hearts beat at a resting rate of 60 to 100 beats per minute. Lots of other things pulse, too. The colors we see and the pitches we hear, for example, are due to the different wave frequencies ("pulses") of light and sound waves.
Now, a study in the journal Geoscience Frontiers finds that Earth itself has a pulse, with one "beat" every 27.5 million years. That's the rate at which major geological events have been occurring as far back as geologists can tell.
A planetary calendar has 10 dates in red
Credit: Jagoush / Adobe Stock
According to lead author and geologist Michael Rampino of New York University's Department of Biology, "Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random."
The new study is not the first time that there's been a suggestion of a planetary geologic cycle, but it's only with recent refinements in radioisotopic dating techniques that there's evidence supporting the theory. The authors of the study collected the latest, best dating for 89 known geologic events over the last 260 million years:
- 29 sea level fluctuations
- 12 marine extinctions
- 9 land-based extinctions
- 10 periods of low ocean oxygenation
- 13 gigantic flood basalt volcanic eruptions
- 8 changes in the rate of seafloor spread
- 8 times there were global pulsations in interplate magmatism
The dates provided the scientists a new timetable of Earth's geologic history.
Tick, tick, boom
Credit: New York University
Putting all the events together, the scientists performed a series of statistical analyses that revealed that events tend to cluster around 10 different dates, with peak activity occurring every 27.5 million years. Between the ten busy periods, the number of events dropped sharply, approaching zero.
Perhaps the most fascinating question that remains unanswered for now is exactly why this is happening. The authors of the study suggest two possibilities:
"The correlations and cyclicity seen in the geologic episodes may be entirely a function of global internal Earth dynamics affecting global tectonics and climate, but similar cycles in the Earth's orbit in the Solar System and in the Galaxy might be pacing these events. Whatever the origins of these cyclical episodes, their occurrences support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is quite different from the views held by most geologists."
Assuming the researchers' calculations are at least roughly correct — the authors note that different statistical formulas may result in further refinement of their conclusions — there's no need to worry that we're about to be thumped by another planetary heartbeat. The last occurred some seven million years ago, meaning the next won't happen for about another 20 million years.
When I was a junior in college, my electromagnetism professor had an awesome idea. Apart from the usual homework and exams, we were to give a seminar to the class on a topic of our choosing. The idea was to gauge which area of physics we would be interested in following professionally.
Professor Gilson Carneiro knew I was interested in cosmology and suggested a book by Nobel Prize Laureate Steven Weinberg: The First Three Minutes: A Modern View of the Origin of the Universe. I still have my original copy in Portuguese, from 1979, that emanates a musty tropical smell, sitting on my bookshelf side-by-side with the American version, a Bantam edition from 1979.
Inspired by Steven Weinberg
Books can change lives. They can illuminate the path ahead. In my case, there is no question that Weinberg's book blew my teenage mind. I decided, then and there, that I would become a cosmologist working on the physics of the early universe. The first three minutes of cosmic existence — what could be more exciting for a young physicist than trying to uncover the mystery of creation itself and the origin of the universe, matter, and stars? Weinberg quickly became my modern physics hero, the one I wanted to emulate professionally. Sadly, he passed away July 23rd, leaving a huge void for a generation of physicists.
What excited my young imagination was that science could actually make sense of the very early universe, meaning that theories could be validated and ideas could be tested against real data. Cosmology, as a science, only really took off after Einstein published his paper on the shape of the universe in 1917, two years after his groundbreaking paper on the theory of general relativity, the one explaining how we can interpret gravity as the curvature of spacetime. Matter doesn't "bend" time, but it affects how quickly it flows. (See last week's essay on what happens when you fall into a black hole).
The Big Bang Theory
For most of the 20th century, cosmology lived in the realm of theoretical speculation. One model proposed that the universe started from a small, hot, dense plasma billions of years ago and has been expanding ever since — the Big Bang model; another suggested that the cosmos stands still and that the changes astronomers see are mostly local — the steady state model.
Competing models are essential to science but so is data to help us discriminate among them. In the mid 1960s, a decisive discovery changed the game forever. Arno Penzias and Robert Wilson accidentally discovered the cosmic microwave background radiation (CMB), a fossil from the early universe predicted to exist by George Gamow, Ralph Alpher, and Robert Herman in their Big Bang model. (Alpher and Herman published a lovely account of the history here.) The CMB is a bath of microwave photons that permeates the whole of space, a remnant from the epoch when the first hydrogen atoms were forged, some 400,000 years after the bang.
The existence of the CMB was the smoking gun confirming the Big Bang model. From that moment on, a series of spectacular observatories and detectors, both on land and in space, have extracted huge amounts of information from the properties of the CMB, a bit like paleontologists that excavate the remains of dinosaurs and dig for more bones to get details of a past long gone.
How far back can we go?
Confirming the general outline of the Big Bang model changed our cosmic view. The universe, like you and me, has a history, a past waiting to be explored. How far back in time could we dig? Was there some ultimate wall we cannot pass?
Because matter gets hot as it gets squeezed, going back in time meant looking at matter and radiation at higher and higher temperatures. There is a simple relation that connects the age of the universe and its temperature, measured in terms of the temperature of photons (the particles of visible light and other forms of invisible radiation). The fun thing is that matter breaks down as the temperature increases. So, going back in time means looking at matter at more and more primitive states of organization. After the CMB formed 400,000 years after the bang, there were hydrogen atoms. Before, there weren't. The universe was filled with a primordial soup of particles: protons, neutrons, electrons, photons, and neutrinos, the ghostly particles that cross planets and people unscathed. Also, there were very light atomic nuclei, such as deuterium and tritium (both heavier cousins of hydrogen), helium, and lithium.
Cosmic alchemy
So, to study the universe after 400,000 years, we need to use atomic physics, at least until large clumps of matter aggregate due to gravity and start to collapse to form the first stars, a few millions of years after. What about earlier on? The cosmic history is broken down into chunks of time, each the realm of different kinds of physics. Before atoms form, all the way to about a second after the Big Bang, it's nuclear physics time. That's why Weinberg brilliantly titled his book The First Three Minutes. It is during the interval between one-hundredth of a second and three minutes that the light atomic nuclei (made of protons and neutrons) formed, a process called, with poetic flair, primordial nucleosynthesis. Protons collided with neutrons and, sometimes, stuck together due to the attractive strong nuclear force. Why did only a few light nuclei form then? Because the expansion of the universe made it hard for the particles to find each other.
What about the nuclei of heavier elements, like carbon, oxygen, calcium, gold? The answer is beautiful: all the elements of the periodic table after lithium were made and continue to be made in stars, the true cosmic alchemists. Hydrogen eventually becomes people if you wait long enough. At least in this universe.
In this article, we got all the way up to nucleosynthesis, the forging of the first atomic nuclei when the universe was a minute old. What about earlier on? How close to the beginning, to t = 0, can science get? Stay tuned, and we will continue next week.
To Steven Weinberg, with gratitude, for all that you taught us about the universe.
Before Alexander the Great established Alexandria around 331 BCE, one of Egypt's primary ports on the Mediterranean Sea between the sixth and fourth centuries BCE was a place called Thônis-Heracleion.
Now researchers from the European Institute for Underwater Archaeology (IEASM), the same organization that first found the city in 2001, have announced the discovery of a couple of fascinating items from the city's heyday. Pinned beneath fallen temple stones is a surprisingly intact Egyptian military vessel from the second century BCE, and researchers have excavated a large cemetery from the fourth century BCE.
Thônis-Heracleion
Credit: Egyptian Ministry of Tourism and Antiques
Thônis-Heracleion was one of the two primary access points to ancient Egypt from the Mediterranean. (The other, Canopus, was discovered in 1999.) For millennia, experts assumed Thônis-Heracleion were two different lost cities, but it's now known that Thônis is simply the city's Egyptian name, while Heracleion is its Greek name.
Thônis-Heracleion had been the stuff of legend before it was located, mentioned only in rare ancient texts and stone inscriptions. Herodotus seems to have been referring to Thônis-Heracleion's temple of Amun as the place where Heracles first arrived in Egypt. He also described a visit there by Helen with her lover Paris just before the outbreak of the Trojan War. In addition, 400 years later, geographer Strabo wrote that Heraclion, containing the temple of Heracles, had been located opposite Canopus across a branch of the Nile. Today we know Thônis-Heracleion's location as Egypt's Abu Qir Bay. The sunken port is about 6.5 kilometers from the coast and lies beneath ten meters of water.
Both Thônis-Heracleion and Canopus were wealthy in their day, and the temple was an important religious center. This all ended when the Egyptian dynasty created by Ptolemy set out to establish Alexandria as Egypt's center. Thônis-Heracleion and Canopus' trade — and thus wealth — was diverted to the new capital.
It was perhaps just as well, given that natural forces eventually destroyed Thônis-Heracleion. Located on the Mediterranean, the ground upon which it was built became saturated and eventually began to destabilize and liquefy. The temple of Amun probably collapsed around 140 BCE. A series of earthquakes sealed the cty's' fate around 800 CE, sending a 100 square-kilometer chunk of the Nile delta on which it was constructed under the waves. The Mediterranean's rising sea level over the next couple thousand years completed the drowning of Thônis-Heracleion.
Researchers have recovered a large collection of Thônis-Heracleion's treasures revealing an economically rich culture. Coins, bronze statuettes, and over 700 ancient ship anchors have been pulled from the waters. Divers have also identified over 70 shipwrecks. A giant statue of the Nile god Hapi took two and a half years to bring up.
An ancient vessel and a cemetery
Gold mask found in a submerged Greek cemetery.Credit: Egyptian Ministry of Tourism and Antiques
The newly discovered ship was found beneath 16 feet of hard clay, "thanks to cutting-edge prototype sub-bottom profiler electronic equipment," says Ayman Ashmawy of the Egyptian Ministry of Tourism and Antiques.
The military vessel had been moored in Thônis-Heracleion when the temple of Amun collapsed. The temple's enormous blocks fell onto the ship, sinking it. The boat is a rare find — only one other ship of its period has been found. As underwater archaeologist Franck Goddio, one of the scientists who found the city, puts it, "Finds of fast ships from this age are extremely rare."
At 80 feet long, the boat is six times as long as it is wide. Like its dually-named city, it's an amalgam of Greek and Egyptian ship-building techniques. According to expert Ehab Fahmy, head of the Central Department of Underwater Antiquities at IEASM, the boat has some classical construction features such as mortar and tenon joints. On the other hand, it was built to be rowed, and some of its wood was reused lumber, signature traits of Egyptian boat design. Its flat bottom suggests it was built for navigating the shallows of the Nile delta where the river flows into the Mediterranean.
Also found alongside the city's submerged northeastern entrance canal was a large Greek cemetery. The funerary is adorned with opulent remembrances, including a mask made of gold, shown above. A statement by the Egyptian Ministry of Tourism and Antiques describes its significance, as reported by Reuters:
"This discovery beautifully illustrates the presence of the Greek merchants who lived in that city. They built their own sanctuaries close to the huge temple of Amun. Those were destroyed simultaneously and their remains are found mixed with those of the Egyptian temple."
Excavation is ongoing, with more of Egypt's ancient history no doubt waiting beneath the waves.
