Category Archives: Nature & Space

Differences in Human and Neanderthal Brains Explain Human Exceptionalism

When I was a little kid, my mom went through an Agatha Christie phase. She was a huge fan of the murder mystery writer and she read all of Christie’s books.

Agatha Christie was caught up in a real-life mystery of her own when she disappeared for 10 days in December 1926 under highly suspicious circumstances. Her car was found near her home, close to the edge of a cliff. But, she was nowhere to be found. It looked as if she disappeared without a trace, without any explanation. Eleven days after her disappearance, she turned up in a hotel room registered under an alias.

Christie never offered an explanation for her disappearance. To this day, it remains an enduring mystery. Some think it was a callous publicity stunt. Some say she suffered a nervous breakdown. Others think she suffered from amnesia. Some people suggest more sinister reasons. Perhaps, she was suicidal. Or maybe she was trying to frame her husband and his mistress for her murder.

Perhaps we will never know.

Like Christie’s fictional detectives Hercule Poirot and Miss Marple, paleoanthropologists are every bit as eager to solve a mysterious disappearance of their own. They want to know why Neanderthals vanished from the face of the earth. And what role did human beings (Homo sapiens) play in the Neanderthal disappearance, if any? Did we kill off these creatures? Did we outcompete them or did Neanderthals just die off on their own?

Anthropologists have proposed various scenarios to account for the Neanderthals’ disappearance. Some paleoanthropologists think that differences in the cognitive capabilities of modern humans and Neanderthals help explain the creatures’ extinction. According to this model, superior reasoning abilities allowed humans to thrive while Neanderthals faced inevitable extinction. As a consequence, we replaced Neanderthals in the Middle East, Europe, and Asia when we first migrated to these parts of the world.

Computational Neuroanatomy

Innovative work by researchers from Japan offers support for this scenario.1 Using a technique called computational neuroanatomy, researchers reconstructed the brain shape of Neanderthals and modern humans from the fossil record. In their study, the researchers used four Neanderthal specimens:

  • Amud 1 (50,000 to 70,000 years in age)
  • La Chapelle-aux Saints 1 (47,000 to 56,000 years in age)
  • La Ferrassie 1 (43,000 to 45,000 years in age)
  • Forbes’ Quarry 1 (no age dates)

They also worked with four Homo sapiens specimens:

  • Qafzeh 9 (90,000 to 120,000 years in age)
  • Skhūl 5 (100,000 to 135,000 years in age
  • Mladeč 1 (35,000 years in age)
  • Cro-Magnon 1 (32,000 years in age)

Researchers used computed tomography scans to construct virtual endocasts (cranial cavity casts) of the fossil brains. After generating endocasts, the team determined the 3D brain structure of the fossil specimens by deforming the 3D structure of the average human brain so that it fit into the fossil crania and conformed to the endocasts.

This technique appears to be valid, based on control studies carried out on chimpanzee and bonobo brains. Using computational neuroanatomy, researchers can deform a chimpanzee brain to accurately yield the bonobo brain, and vice versa.

Brain Differences, Cognitive Differences

The Japanese team learned that the chief difference between human and Neanderthal brains is the size and shape of the cerebellum. The cerebellar hemisphere is projected more toward the interior in the human brain than in the Neanderthal brain and the volume of the human cerebellum is larger. Researchers also noticed that the right side of the Neanderthal cerebellum is significantly smaller than the left side—a phenomenon called volumetric laterality. This discrepancy doesn’t exist in the human brain. Finally, the Japanese researchers observed that the parietal regions in the human brain were larger than those regions in Neanderthals’ brains.

Because of these brain differences, the researchers argue that humans were socially and cognitively more sophisticated than Neanderthals. Neuroscientists have discovered that the cerebellum helps motor functions and higher cognition by contributing to language function, working memory, thought, and social abilities. Hence, the researchers argue that the reduced size of the right cerebellar hemisphere in Neanderthals limits the connection to the prefrontal regions—a connection critical for language processing. Neuroscientists have also discovered that the parietal lobe plays a role in visuo-spatial imagery, episodic memory, self-related mental representations, coordination between self and external spaces, and sense of agency.

On the basis of this study, it seems that humans either outcompeted Neanderthals for limited resources—driving them to extinction—or simply were better suited to survive than Neanderthals because of superior mental capabilities. Or perhaps their demise occurred for more sinister reasons. Maybe we used our sophisticated reasoning skills to kill off these creatures.

Did Neanderthals Make Art, Music, Jewelry, etc.?

Recently, a flurry of reports has appeared in the scientific literature claiming that Neanderthals possessed the capacity for language and the ability to make art, music, and jewelry. Other studies claim that Neanderthals ritualistically buried their dead, mastered fire, and used plants medicinally. All of these claims rest on highly speculative interpretations of the archaeological record. In fact, other studies present evidence that refutes every one of these claims (see Resources).

Comparisons of human and Neanderthal brain morphology and size become increasingly important in the midst of this controversy. This recent study—along with previous work (go here and here)—indicates that Neanderthals did not have the brain architecture and, hence, cognitive capacity to communicate symbolically through language, art, music, and body ornamentation. Nor did they have the brain capacity to engage in complex social interactions. In short, Neanderthal brain anatomy does not support any interpretation of the archaeological record that attributes advanced cognitive abilities to these creatures.

While this study provides important clues about the disappearance of Neanderthals, we still don’t know why they went extinct. Nor do we know any of the mysterious details surrounding their demise as a species.

Perhaps we will never know.

But we do know that in terms of our cognitive and social capacities, human beings stand apart from Neanderthals and all other creatures. Human brain biology and behavior render us exceptional, one-of-a-kind, in ways consistent with the image of God.

Original article: Differences in Human and Neanderthal Brains Explain Human Exceptionalism

Advertisements

List of solar eclipses in the 20th century BC

sunbeam

This is a list of solar eclipses in the 20th century BC. During the period 2000 to 1901 BC there were 239 solar eclipses of which 84 were partial, 71 were annular (one non-central), 62 were total, and 22 were hybrids. The greatest number of eclipses in one year was four, occurring in 10 different years: 1998 BC, 1983 BC, 1980 BC, 1958 BC, 1940 BC, 1926 BC, 1922 BC, 1918 BC, 1911 BC, and 1904 BC. One month, March 1958 BC, had two eclipses.

Continued…

From Wikipedia: List of solar eclipses in the 20th century BC

Probing the Moment of Creation with Large-Scale Magnetic Fields

In the past one hundred years astronomers have moved from knowing virtually nothing about the origin and history of the universe to possessing a detailed and abundantly confirmed cosmic creation model. I describe this journey and all the observational successes of what is now known as the big bang creation model in my latest book, The Creator and the Cosmos.1

The only time window over which astronomers lack a detailed knowledge of cosmic history are the events that occur in the first millionth of a second after the cosmic creation event. Now they are getting some help, however, from a paradoxical source—extremely large-scale magnetic fields. “Extremely large-scale” is an understatement. In a recent paper2 published in the Astrophysical Journal, astronomers Justin Bray and Anna Scaife from the University of Manchester used measurements of ultra-high-energy cosmic rays to determine the strength of magnetic fields on size scales less than 100 megaparsecs (326 million light-years) across and on size scales greater than 100 megaparsecs across. One hundred megaparsecs is equivalent to the distance between Earth and the center of the Coma cluster of over 1,000 galaxies. (More than ten clusters of galaxies reside closer to us than the Coma cluster.)

Large-Scale Magnetic Fields and the Early Moments of Creation

In the biblically predicted big bang creation modelthe universe begins infinitely or near infinitely hot. This heat means that the four forces of physics (gravity, strong nuclear force, weak nuclear force, and electromagnetism) were united into a single force.

As the universe expands from the cosmic creation event, it becomes increasingly cooler (see figure 1). At 10-43 seconds after the cosmic creation event, the one superforce separates into gravity and the strong-electroweak force. At 10-36 seconds, the strong-electroweak force separates into the strong nuclear force and the electroweak force. At 10-12 seconds, the electroweak force separates into the weak nuclear force and the electromagnetic force. Finally, at 10-6 seconds after the cosmic creation event, the universe has cooled sufficiently that quarks can bind together to make protons and neutrons.

blog__inline--probing-the-moment-of-creation-with-large-scale-magnetic-fields-1

Figure 1: Temperature Measurements of the Universe with Respect to Time after the Cosmic Creation Event. Image credit: Graph was created by the author from published measurements.

At one or more of these transition events, it is possible for some of the free energy released during the phase transitions to be converted into what later becomes large-scale (size scale exceeding 3 million light-years) magnetic fields. Astronomers possess no other conceivable explanation for the possible existence of such large-scale magnetic fields other than their origination in one or more of these very early transition events. Hence, they refer to such magnetic fields as “primordial magnetic fields.”

The potential of primordial magnetic fields to yield a detailed picture of the earliest moments after the cosmic creation event explains why the quest to find and measure primordial magnetic fields has become the latest holy grail of cosmology. There are other reasons why astronomers are excited about primordial magnetic fields. If these fields are as strong as one ten-billionth of a gauss, they would explain the hint of non-gaussianity seen in the Planck map (see figure 2) of the radiation left over from the cosmic creation event (a.k.a. the cosmic microwave background radiation, CMBR). They would also explain the one-millionth-gauss magnetic fields that astronomers see in spiral galaxies as large or larger than our Milky Way Galaxy.

blog__inline--probing-the-moment-of-creation-with-large-scale-magnetic-fields-2

Figure 2: Planck Spacecraft Map of the Cosmic Microwave Background Radiation. The red and orange colors represent very slightly higher temperatures than the blue and green spots. Note the apparently slightly hotter region toward the right center. Image credit: European Space Agency

Latest Measurements of Primordial Magnetic Fields

The Planck map would look very different from what it does if primordial magnetic fields were as strong as a nanogauss (1 nanogauss = a billionth of a gauss). Therefore, there is no doubt that primordial magnetic fields must be weaker than a nanogauss. Only in the last decade have astronomers possessed instruments with the capability of detecting large-scale magnetic fields weaker than a nanogauss.

In 2010, astronomers Andrii Neronov and Ievgen Vovk, based on their nondetection of billion-electron-volt gamma-ray emission from a cascade initiated by trillion-electron-volt gamma rays that they observed in blazarsestablished that the strength of intergalactic magnetic fields must be greater than 3 x 10-7 nanogauss.4 This nondetection meant that primordial magnetic fields really do exist and, thus, that they will prove to be useful probes of the earliest moments of the history of the universe.

Almost a year ago to this day, astronomers Dylan Sutton, Chang Feng, and Christian Reichardt combined data from the four best maps of the CMBR, namely from Planck, BICEP2/Keck Array, POLARBEAR, and SPTpol. Their analysis of these maps showed that intergalactic magnetic fields on size scales larger than 3 million light-years could not be any stronger than 0.91 nanogauss.5

Now, Bray and Scaife have established a superior upper limit on the strength of primordial galactic fields. They noted that the trajectories of ultra-high-energy cosmic rays will be deflected as they pass through magnetic fields and that the magnitude of the deflection determines the measure of the magnetic field. They also noted that recently published observations from the Pierre Auger Observatory show that ultra-high-energy cosmic rays indeed originate from extragalactic sources.6 Based on the now strongly affirmed assumption that ultra-high-energy cosmic rays originate from sources outside our galaxy, Bray and Scaife determined that for size scales larger than 100 megaparsecs across, the magnetic field strength must be less than 0.07–0.22 nanogauss.7

This new upper limit is 4–12 times superior to any previous measurement. For the first time, astronomers possess a measurement in range of the value—namely 0.10 nanogauss—where implications for cosmic creation models, and especially for the early moments after the cosmic creation event, get interesting. Astronomers are about to determine additional extreme fine-tuning features of the universe that point to supernatural design. These measurements and others that are soon to follow mean that we can look forward to an even stronger evidential case for the biblically predicted big bang creation model and for the exquisite—that is, supernatural—fine-tuning of the universe that makes possible our existence, civilization, and redemption from evil.8

Original article: Probing the Moment of Creation with Large-Scale Magnetic Fields