Tag: Thomas Stig Wikman

Humans and Chimpanzees Have a Common Ancestor

Super fact 81 : Humans are not descended from chimpanzees, or monkeys, or any other primate living today. However, humans and chimpanzees share a common ancestor that lived roughly 5 to 7 million years ago. The two species evolved separately to become modern humans and chimpanzees. Humans and chimpanzees are closely related and share approximately 98.8% of their DNA. Studying the DNA, it is possible to determine how long ago this ancestor lived despite not having any fossils from this ancestor.

Chimpanzee genome sequencing and the sequencing of human DNA has led to the realization that human and chimpanzee DNA is very similar and that humans and chimpanzees share an ancestor. The fact that the great apes have 48 (24 pairs) chromosomes while humans have 46 (23 pairs) is not an issue. What happened was that the ancestral chromosomes corresponding to modern chimpanzee chromosomes 2A and 2B fused to create human chromosome 2. We can see that the genes in 2A and 2B line up with chromosome 2 and we can also see where the 2A and 2B merge in the human chromosome 2 (see picture below).

The picture is a graph that shows that gorillas, chimpanzees and humans share a common ancestor with orangutans. In turn bonobos, chimpanzees and humans share a common ancestor with gorillas and finally chimpanzees and bonobos share a common ancestor with humans. | Humans and Chimpanzees Have a Common Ancestor
Evolution of humans via phylogenetics and differentiation between humans, chimpanzees, and other primates. Shutterstock Asset id: 2448150743 by kanyanat wongsa

The graph above shows that gorillas, chimpanzees and humans share a common ancestor with orangutans. At the next level bonobos, chimpanzees and humans share a common ancestor with gorillas and finally chimpanzees and bonobos share a common ancestor with humans. We can deduct these things from DNA without needing fossils. We have found millions of fossils corresponding to more than 250,000 species. However, the best evidence for so called “macro evolution” and the best tool for determining relationships between species may not be the fossil record but DNA.

It should be noted that the terms “macro-evolution” and “micro-evolution” are terms that creationists like to use but that scientists do not like to use. Creationists like to say that microevolution is possible (it is observed) but not macroevolution. However, macroevolution is the result of repeated microevolution, so you cannot claim that microevolution is possible but not macroevolution. In addition, speciation is relative. An animal A may be able to successfully interbreed with an animal B, and that animal B may be able to successfully interbreed with an animal C, but animal A and C cannot interbreed.  The border between microevolution and macroevolution is fuzzy.

The fact that we can determine evolutionary ancestry by sequencing DNA of living creatures may come as a surprise to many people. In addition, we can also determine how long ago a common ancestor lived. It may also come as an additional surprise to many that we are not descended from the great apes but share a common ancestor. Super fact 81 is a super fact because we know it is true, it is surprising to many, and important to know.

Identifying a common ancestor using DNA Sequencing

Below is a very high-level image of human and chimpanzee chromosomes referred to as a Karyotype. A karyotype is a laboratory-produced image or visual profile of an individual’s complete set of chromosomes, arranged in pairs by size, shape, and number.

The pictures show the set of the human 46 chromosomes on the left and the set of the chimpanzee 48 chromosomes on the right. The chromosomes look very similar between the two species, except human chromosome 2 which is split into chromosome 2A and 2B in the chimpanzee.
Comparison between human and chimpanzee karyotypes isolated on background. Shutterstock Asset id: 2432966649 by kanyanat wongsa

Based on the similarity in transposons, or jumping genes, pseudo genes, and genes in general (all of the genome) we know that the closest related living animals to humans are chimpanzees and bonobos. You can read more about this in the book Relics of Eden by Daniel Fairbanks, a book I highly recommend. According to the author the latest and perhaps best evidence for evolution as well as the fact that humans and chimpanzees have a common ancestor comes from so called junk-DNA. DNA that is not currently used but contains scientifically informative remnants of our evolutionary ancestry trapped in our DNA. The author refers to these remnants as relics.

Hominini species

Another interesting fact derived from DNA research is that chimpanzees and humans are more closely related than chimpanzees than to the other great apes. Based on the genetic record chimpanzees are no longer classified as great apes but as Hominini together with humans. The fact that there are three Hominini species (homo sapies – us humans, chimpanzees and bonobos) could maybe be another super fact.

Homo skull changes of hominids from Wikipedia<>. SimplisticReps, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons.

Speaking about hominini species, we have found more than 6,000 hominin fossils corresponding to dozens of species including Australopithecus, Paranthropus, Homo Habilis, Homo Erectus, Homo Heidelbergensis, Homo Neanderthalis, and Homo Sapiens. This link features a cool phylogenetic tree that includes Homo Sapiens (us), Neanderthals, as well as chimpanzees and bonobos.

Other Evolution Related Super Facts

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Conic Sections are the Shapes that Shape Our World

Super fact 80 : A conic section is a shape formed by slicing a cone with a plane. There are four such shapes, circle, ellipse, parabola, and hyperbola. The conic sections universally describe motion under gravity. The orbits of planets around their stars are circles or ellipses, comets fly around space in elliptical orbits, or parabolic or hyperbolic paths. Objects thrown up in the air follow parabolic paths. They are the basis for a huge amount of engineering applications.

Esther’s writing prompt: January 21 : Shapes

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Four cones each shown with a plane section forming a specific conic section. | Conic Sections are the Shapes that Shape Our World
Types of conic sections : circle , ellipse , parabola , hyperbola Shutterstock Asset id: 2377159367 by ProfDesigner

The four conic sections, circle, ellipse, parabola and hyperbola are fundamental and very useful shapes in mathematics, physics and engineering. Well, a circle is a special case of an ellipse, so it is really only three conic sections. The motion of the planets and other stellar objects are described by the conic shapes. Isaac Newton derived his law of gravitation from Kepler’s laws, which describe planetary orbits as ellipses.

The conic sections are all described by second degree equations (quadratic equations) and are in that sense the simplest shapes aside from points and lines. It is important to understand that there is an infinite amount of shapes that are almost conic sections and look like conic sections, but it is the exact mathematical properties of the four conic sections that make them so common in physics, mathematics, nature and engineering.

The picture shows a cone with four planes slicing the cone in four ways. The resulting shapes are circle (red), ellipse (green), parabola (blue), hyperbola (orange).
The black boundaries of the colored regions are conic sections. Not shown is the other half of the hyperbola, which is on the unshown other half of the double cone. by Magister Mathematicae, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18556148

It may not come as a surprise that the circle is a fundamental and important shape, but I believe that the fact that the other conic sections are also fundamental in mathematics, physics and engineering come as a surprise to people outside of the STEM fields. It is a true and an important fact regarding how our world works.

Conic Sections

As mentioned, the conic sections are fundamental shapes that appear in a lot of places in STEM. Below are a few examples.

Parabola

Math function parabola graphics illustration with a dark background. | Conic Sections are the Shapes that Shape Our World
Math function parabola. Shutterstock Asset id: 1628916337 by EleonoraDesigner

A parabola is formed when a plane cuts a cone, so the plane is parallel to a side of the cone. Parabolas are shapes that are roughly U-shaped and described by the equation y = x^2 or more generally by y = ax^2 + bx + c. Parabolas have a so called focus point. See the picture below. If you throw a ball, or any object, up in the air its trajectory will be a parabola (ignoring distortions caused by friction and wind). I should say the parabola you get in this case is upside down. The parabola is important when you design any kind of projectile.

U-shaped parabola with the focus shown. The pciture has an x-axis and a y-axis.
Part of a parabola (blue), with various features (other colours). The complete parabola has no endpoints. In this orientation, it extends infinitely to the left, right, and upward. Picture is from Wikipedia Melikamp, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons.

Antennas shaped like parabolas (in 3D) will direct incoming radiation and waves towards their focus point. If the surface is reflective a light located at the focus point will reflect to create a straight beam. Parabolas are used for radio telescopes, satellite dishes, car headlights, flashlights, solar cookers, solar power plants, water fountains, suspension bridges, business modelling and thousands of engineering applications. Parabolas like circles and the other conic sections shape our modern world (pun intended).

A parabola dish with equipment located at the focus.
Würzburg-Riese radar built by Germany in WW2 had a 7.4 meter (24 foot) dish. From this page. Alan Wilson from Stilton, Peterborough, Cambs, UK, CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0, via Wikimedia Commons

Ellipse and circle

As mentioned, a circle and an ellipse are conic sections formed by intersecting a plane with a cone. You get a circle when the cuts perpendicular to the cone’s axis (see pictures above) and an ellipse form when the plane intersects the cone at a slant but not slanted so much that it becomes a parabola or a hyperbola. An alternative for an ellipse is that the sum of the distances from any point on the curve to two fixed points (called the foci) is a constant. See the picture below. The two definitions are identical. For a circle the two foci are merged into one point at the center.

The picture shows an ellipse and its two foci points. From the foci points there are lines going to a point P on the ellipse. The length of the two lines are added together and is the sum “2a” no matter where on the ellipse the point P is located. | Conic Sections are the Shapes that Shape Our World
Ellipse: definition by sum of distances to foci. Ag2gaeh, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons

There are a lot of real world examples of ellipses. Planets orbit the Sun in elliptical paths. The sun is in one of the foci points. The orbits of other stellar objects and satellites are also elliptical. Charged particles follow elliptical paths within magnetic fields.  Elliptical patterns are observed in the rotation of ocean currents, elliptical models and algorithms are used in medical imaging, computer science and encryption. Also whispering galleries.

Hyperbola

Comets and spacecraft that are not orbiting another body, in other words, they have enough speed to escape the gravitational pull and continue into deep space, will travel along a hyperbola. The boundary of a shockwave from a supersonic jet (a sonic boom) creates a hyperbolic curve on the ground as it moves. The intersection of two sets of concentric ripples in water makes a hyperbola. The light beam from a lamp or flashlight makes an ellipse or an hyperbola on a plane depending on the angle.

Newton’s Law of Gravitation

Johannes was an early 17th century German mathematician who derived three laws that describe how planetary bodies orbit the Sun using the observational data collected by the Danish astronomer Tycho Brahe. The three laws are the following:

  • Planets move in elliptical orbits with the Sun as a focus.
  • A planet covers the same area of space in the same amount of time no matter where it is in its orbit.
  • A planet’s orbital period is proportional to the size of its orbit (its semi-major axis).
Kepler’s three laws are illustrated in a diagram for two planets.
Illustration of Kepler’s laws with two planetary orbits.
The orbits are ellipses, with foci F1 and F2 for Planet 1, and F1 and F3 for Planet 2. The Sun is at F1.
The shaded areas A1 and A2 are equal and are swept out in equal times by Planet 1’s orbit.
The ratio of Planet 1’s orbit time to Planet 2’s is (a1/a2)^3/2
Hankwang, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons

Later Isaac Netwon would use Kepler’s three laws to derive his law of gravity. Newton showed that an inverse-square force (gravity) directed toward the sun was necessary to explain the orbits.

My Other Responses to Esther’s Prompts

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The Universe has a Redshift and its Increasing

Super fact 79 : Distant galaxies appear redder (redshifted) because of the universe’s expansion. The farther away the galaxy, the redder it is. This cosmological redshift is also increasing because the Universe’s expansion is accelerating. Our Universe is getting more and more red every day.

Esther’s writing prompt: January 14 : Red

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Many people are aware that the Universe is expanding but may not know that this results in a measurable redshift. The faster a galaxy is moving away from us the redder it appears. This is called the cosmological redshift. Measuring these redshifts was how we discovered that our Universe is expanding.

Cosmological redshift vector illustration. Stretched and original space wavelength with earth and distant galaxy. Doppler effect astronomical phenomenon distance example. | The Universe has a Redshift and its Increasing
As the Universe expands and galaxies are moving away from each other the light will be stretched. Stretched light with longer wavelengths are more red. The phenomenon is called redshift. Shutterstock Asset id: 1180828402 by VectorMine.

At the end of the 1990’s it was also discovered that the Universe’s expansion was accelerating. This discovery came from measuring the redshifts (and apparent dimness) of distant Type Ia supernovae. I should add that measuring the increase in the cosmological redshift directly is difficult. However, it is expected to be possible when the Extremely Large Telescope (ELT) starts gathering data in 2027. I can add that there are also other types of evidence showing that the Universe’s expansion is accelerating.

Another surprising aspect is, if the Big Bang was like an explosion, gravity would pull back the galaxies making the expansion slow down and perhaps eventually even reverse. However, the opposite is happening. A common explanation is that a repulsive force, a sort of anti-gravity, referred to as dark energy, is responsible for this acceleration.

I call this a super fact because this is an observed phenomenon, it is important knowledge for how we view the world, and it is surprising. Many people have heard bits and pieces of this but do not have the fuller picture.

The Doppler Effect

The cosmological redshift is an example of the so called doppler effect. The doppler effect is the change in the frequency or wavelength of a wave in relation to an observer if the origin of the wave and the observer are moving compared to each other. If an object is moving towards you, let say an ambulance, the frequency of its sound will be higher (wavelength shorter).

After it passes you and moves away from the frequency will be lower (wavelength longer). In other words, the sound changes when the ambulance passes you. The same is true for other kinds of waves, including waves on the water, and light. If a light is travelling towards you at a high speed, it will look bluer. If a light is travelling away from you at a high speed it will look redder. The latter is what is called a redshift, cosmological redshift in our case.

The object is indicated by a red dot, and a red arrow indicates the direction of motion.
Change of wavelength caused by motion of the source. When an object moves toward you the wavelengths get shorter and the frequency higher. When an object moves away from you the wavelengths get longer and the frequency lower. Original: Tkarcher Vector:  Tatoute, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons
An animation illustrating how the Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The red circles represent sound waves.
The Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The red circles represent sound waves. Charly Whisky 18:20, 27 January 2007, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons

Below is a three minute video explaining the doppler effect and redshift.

I can add that the constancy of the speed of light in vacuum changes the exact size of the doppler effect. The doppler effect remains as is for the most part but the formulas for the classical doppler effect, which you would use for sound, and the relativistic doppler effect, which you would use for light in space, are different. It is just to pick the right formula.

Doppler Effect Formula on a green chalkboard. Education. Science. Formula. Vector illustration. | The Universe has a Redshift and its Increasing
The classical formula for the doppler effect. There is a medium (air) but you don’t need to consider the constancy of the speed of light in vacuum. You use it for sound and water waves. Shutterstock Asset id: 2365938267 by Sasha701.
Relativistic Doppler Effect Formula on a black chalkboard. Education. Science. Formula. Vector illustration.
The relativistic formula for the doppler effect considers the constancy of the speed of light in vacuum but there is no medium to worry about. You use this formula for the doppler effect of light in space. Shutterstock Asset id: 2416786951 by Sasha701.

Measuring redshift

A common misconception is that astronomers take pictures of distant galaxies and somehow measure the “redness” of them, but that is not the case. When you take a spectrum of a heated element (such as hydrogen or helium in stars) it creates characteristic dark lines in the spectrum — like a fingerprint. Everything on the periodic table has its own characteristic fingerprint of lines at characteristic frequencies. In addition to measuring the cosmological redshift it makes it possible to identify the elements in a star and their proportions. See the picture below.

The top shows a colorful spectrum from blue to red with absorption lines in black. The bottom portion of the picture shows the same thing expect the black absorption lines have moved a bit to the right.
Visualization of redshifted absorption lines are redshifted due to velocity away from observer. Top lines are for an object at rest and in the bottom picture the object is moving away. Maxmath12, CC0, via Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.

Expanding Universe Hazy IPA

Expanding Universe is a Hazy IPA, or a so called New England style IPA from First State Brewing, ABV 6.5%, IBU 25 (IBU = International Bitter Units). The fact that it is an IPA (India Pale Ale) means that it is Ale and therefore not a Lager. The fact that it is an IPA means that it is hop-forward and has an intense flavor and aroma. The fact that it is a Hazy / New England style IPA means that it is more fruity than bitter and looks cloudy, hazy, like juice. The flavor of Expanding Universe is mango, pineapple, and grapefruit. It has a low bitterness, it is fruity, juicy, and it is great if you like New England IPAs.

The picture shows a glass with yellow to light orange hazy liquid. There are green plants in the background.
Expanding Universe ABV 6.5%, IBU 25.

Related Posts

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Landman Lies

Super fact 77 : The TV series Landman portrays several falsehoods about clean energy. Since these claims are mostly unchallenged, appear to be information, and are also very easy to look up and debunk, they are deliberate lies.

“Lies” may be a strong word but if you make a very one sided presentation and you don’t fact check your claims even though that would take less than 30 seconds to do, especially since you are a large company with lots of resources, then you are clearly intentionally deceiving your audience, which is lying. I consider the claim above (in bold) a super fact because it is true, and it is important because it is a popular series and based on the reaction the Landman series has deceived a lot of people.

I got the idea for this super fact yesterday as we were watching a few episodes of Landman. Since I know a little bit about this topic the misinformation was obvious to me. The Landman series is fiction but the way the information was presented made it appear as facts. It appeared as if it was trying to teach us something rather than being the delusional rants of an oilman.

In addition, the misinformation is not minor. It consists of big bold whoppers. Imagine a movie promoting us taking Greenland from Denmark claiming that the Danes attacked Pearl Harbor, acquired a nuclear bomb, and used chemical weapons on Los Angeles. Whatever your opinion on the Greenland situation is, these big whoppers would likely make it harder for you to watch the movie, at least if you know some history. If most people’s knowledge of history was so bad that they’d believe it, then it would also create problems. There is a lot of confusion and misinformation regarding clean energy, and it is a poorly understood topic, so telling big lies does damage.

Photo of a row of wind turbines. | Landman Lies
Wind turbines from pexels.com

It may come as a surprise to many that Paramount plus would deliberately mislead their audience. However, clean energy, climate science, evolution, vaccines, and any science that is inconvenient to some people have been undermined by false information for quite a while. It is just more of it than usual right now. That the executive branch is at war with clean energy might have something to do with it.

Misleading information about clean energy is often spread on social media via fake memes, non-reputable sources, comments by people who do not know what they are talking about, conspiracy theories, small groups of contrarian agenda driven scientists making youTube videos with false information, bots, deep fakes, etc., but now it has also shown up in a major Hollywood Production.

It is more important than ever to be skeptical of claims you hear, especially if they seem to support your own political, ideological, religious, or philosophical views, because that’s how you get bamboozled. Questioning other people’s views does not require much effort. I speak from experience. Intentionally seek the truth not confirmation of your belief. Verify all claims before you take them seriously. Be a realist.

Truth: Windpower and Solar are Much Cleaner than Fossil Fuels

The false claim in the series is that “there is nothing clean about clean energy, that renewables require too much fossil fuel to build to be considered clean.” I am using the true statement as the title of this section because our memories often mix up the false and true statements as time goes by, so highlighting the true statement helps.

Manufacturing, transporting, and building infrastructure for wind power currently involve fossil fuels and so do fossil fuel plants. However, this is only an initial stage. Once wind and solar facilities are built, they generate power without direct emissions, unlike fossil fuel plants which continue to burn fuel and emit CO2 during their entire operational lives. For example, the lifetime emissions of gas-powered generation are estimated to be around 20 to 40 times higher than those of renewables. You can read more here or here.

This is a 3 minute video

Truth: Wind turbines typically offset their carbon footprint within a year

The demonstrably false claim is that “wind turbines do not offset their carbon footprint within their lifespan.” According to energy researchers, for example, the National Renewable Energy Laboratory, a wind turbine typically offsets the carbon emissions from its manufacturing, transport, and installation within six months to one year of operation. In other words, wind turbines offset their carbon footprint quickly. The average lifespan of a wind turbine is over 25 years.

Truth: Solar and Wind Are Cheaper than Gas, Coal and Nuclear

The false claim in Landman is that “solar and wind energy are significantly more expensive than natural gas.” While wind and solar can have higher upfront installation costs, their operational costs are very low as they do not require fuel. Therefore, they can provide electricity very cheaply, making them competitive with and often cheaper than natural gas over their full lifespan.

However, all energy sources are subsidized, and fossil fuels have a long history of government subsidies. Below is the average unsubsidized levelized cost of energy in the United States according to Lazard. Levelized means that construction costs, land rent, and other costs not directly caused by electricity generation are taken into consideration. Notice how cheap wind is (blue line). This is for the United States not just Texas. I don’t have any numbers, but I’ve heard that for Texas solar is the cheapest .

The image shows 8 graphs representing the price of Nuclear, Gas (peaker), Thermal Solar, Coal, Geothermal, Natural Gas, Solar Panels, and Wind. Today Wind is the cheapest.
Average unsubsidized levelized cost of energy. Notice that the light blue line indicates that wind power is pretty cheap. Mir-445511, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

The free market based Texas (my state) grid ERCOT provides an excellent example of how wind and solar effectively compete with other energy sources. ERCOT provides a minute by minute update for the fuel mix percentages. This is a fun website.

Truth: Fossil Fuels are Worse for the Environment than lithium batteries and solar panels

The false claim in Landman is that “Lithium batteries and solar panels are worse for the environment than fossil fuels.” Solar panels typically offset the emissions from their production and installation within 1 to 4 years. Battery technology is continuously improving, and current systems are highly recyclable (90-95%). While the mining of materials like lithium has environmental impacts, the overall lifetime emissions of renewables and associated storage systems are vastly lower than those of fossil fuels.

Truth: Fossil fuels kill a lot more birds than Wind Power per Giga Watt

Tommy Norris (played by Billy Bob Thornton) implies in a rant that “Wind turbines are a major ecological disaster for birds, disrupting patterns and causing mass deaths.” While wind turbines kill some birds it is minor compared to the impacts of the oil and gas industry or other common human activities. This study estimates that wind farms and nuclear power stations are responsible each for between 0.3 and 0.4 fatalities per gigawatt-hour (GWh) of electricity while fossil-fueled power stations are responsible for about 5.2 fatalities per GWh. These articles from MIT provide additional information and reiterate that fossil fuels are lot more deadly to birds than wind power stations. You can read more on this topic here, here, here or here.

The graph shows that Wind Turbines kill 328,000 birds per year in the US, Electrocutions kill 6,250,000 birds, Collisions with powerlines kill 32,500,000 birds, Poison kills 72,000,000 birds, Vehicle collisions kill 214,500,000 birds, Collisions with glass kill 676,500,000 birds, and cats kill 1,850,700,000 birds per year in the US. | Landman Lies
From Wikipedia: Universiteit van Nederland, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0&gt;, via Wikimedia Commons
Bar graph showing cats killing an estimated 2,400 million birds per year, buildings killing an estimated 599 million birds per year, automobiles killing an estimated 200 million birds per year, pesticides killing an estimated 67 million birds per year, powerlines killing an estimated 28 million birds per year, communication towers killing an estimated 6.6 million birds per year, and wind turbines killing an estimated 1.2 million birds per year.
An alternative graph taken from Hannah Richie / Our World in Data, using alternative sources essentially showing the same thing. Sources: Loss et al. (2015), (2013), US Fish and Wildlife Service; Subramnayan et al. (2012), American Bird Conservancy (2021).

Truth: There is no evidence that Offshore Wind Kills Whales

The false claim in Landman is that “offshore wind development, including site characterization surveys, is responsible for a spike in whale deaths”. The primary cause of human-caused threats to large whales are vessel strikes and entanglement in fishing gear but not offshore wind. According to NOAA there are no known links between large whale deaths and ongoing offshore wind activities. You can read more on this topic here, here, or here.

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Jesus was not born on Christmas

Super fact 74 : We celebrate the birth of Jesus on December 25th or December 24th, but it is quite unlikely that Jesus was born on those dates, and certainly not during the year zero.

This AI generated illustration feature baby Jesus in a crib, Mary and Joseph as well as some sheep. | Jesus was not born on Christmas
Jesus Mary and Joseph Birth – This content was generated by an Artificial Intelligence (AI) system. Shutterstock Asset id: 2560713955

I’ve come across many adults who seriously believe that Jesus was born on December 25th. To them it will come as a big surprise to find out that the date of Jesus’ birth is never mentioned in the Gospels, or elsewhere in the Bible, not in any of the non-canonical Gospels, nor in any known historical sources. In addition, Luke’s Gospel mentions (Luke 2:8) shepherds tending flocks outdoors at night, which is not consistent with the cold winter in Judea. Biblical scholars (see 4th and 5th paragraphs in link) suggest that the information in the Gospel of Luke regarding the vision of John the Baptists father, Zechariah, leads to the conclusion that Jesus was likely born in September.

When was Jesus Born?

Jesus was not born during the year zero, because there was no year zero. The year after 1 BC (or BCE) is 1 AD (or CE). This causes problems for various scientific disciplines such as astronomy, climate science and history. The Gospel of Matthew mentioned that the birth took place during the time of Herod the Great who died in the year 4 BCE. I can add that Herod the Great got his moniker “Great” because of his extensive construction of cities, palaces, fortresses, aqueducts, and theaters across Judea, as well as the expansion of the Jewish temple.

The Gospel of Luke (Luke 2:1-2) states that the birth of Jesus took place during the census of the Roman governor of Syria, Quirinius (Cyrenius), which was in the year 6 CE, ten years after the death of Herod. However, there were other census taken earlier and scholars suggest that perhaps Luke’s account is a misstatement and that Mathew’s is more realistic. They conclude that Jesus was most likely born between 6 BCE and 4 BCE.  As already mentioned it is very hard to pin down the time of the year when Jesus was born, but the month of September seems to be a likely candidate.

Herod's Temple as depicted on the Holyland Model of Jerusalem.
Herod was a builder and one of his projects was the expansion of the Temple. Herod’s Temple as depicted on the Holyland Model of Jerusalem. Berthold Werner, Public domain, via Wikimedia Commons.

Why is Christmas on December 25th?

During the first few centuries after the birth of Jesus Christians did not celebrate his birth. The first mention of the birth of Christ on December 25 comes in the 3rd century CE by Hippolytus of Rome. The Roman festival Sol Invictus, celebrating the birth of the Sun God was Celebrated on December 25th. Many pre-Christian cultures marked the shortest day of the year, on December 21 or 22, as an important moment in the calendar, celebrating the “rebirth” of the sun. Germanic peoples celebrated Yule, and various Celtic and Mediterranean cultures held celebrations centered around the winter solstice. It is possible that December 25th was chosen as the day to celebrate the birth of Jesus so that people did not have to change the dates of their celebrations.

Relief in light brown stone featuring the face of the sun God. | A relief of Sol from Roman Lugdunum, 2nd–3rd century AD.
A relief of Sol from Roman Lugdunum, 2nd–3rd century AD. The Roman festival Sol Invictus was celebrated on December 25. Mark Landon, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0&gt;, via Wikimedia Commons

Regarding Germanic peoples celebrating Yule. In my native country Sweden Christmas is referred to as “Jul” pronounced “Yool” / “Yuul”.  The word “Jul” directly comes from the Old Norse word “jól,” which referred to the pre-Christian midwinter festival (Yule in English). You can read about Scandinavian mythology here or here.

A Tomte wearing a red hat in a snowy winter forest.
Tomtar (plural of Tomte) or Nisse in Norwegian is a type of small magical people, or gnomes, related to Vitter folk. They are friendly and is an inspiration behind the Swedish version of Santa Claus. An illustration of a Tomte. Shutterstock ID: 2060057882 by PLIMPLUM.

Note this year Christmas Day is on 12/25/25

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