Super fact – Page 3 – Super Facts

Ten Selected 2025 Super Facts

I started this blog, superfactful, in August of 2024. The goal of my blog is to create a list of facts that are important, not trivia, and that are known to be true yet surprising, shocking or disputed by large segments of the public. I determine what is true by evaluating the evidence I find in reliable reputable sources and if a longstanding scientific consensus is available that certainly helps. In some cases, I have expertise in the subject myself, which also helps. Whether a fact is important and surprising or disputed is a judgment call. In some cases, there are polls to help me determine how surprising or disputed the fact is. I am trying to avoid trivia and click bait, and I am only focusing on what is true, important and mindboggling.

It is a project I hope to learn a lot from, and I hope others will also learn something from reading it. We are all drowning in misinformation, false beliefs and unsubstantiated assumptions. We often know and understand less than we think. I have been bamboozled in the past and I am pretty sure you have too. If this blog can spread a little bit of light, I am happy.

In 2024 I posted 25 super facts and in 2025 I posted 53. I am hoping to one day to have collected 200 super facts. I have also made 64 other kinds of posts on this blog such as book reviews for educational books as well as other fact related posts. Below are ten selected super facts from 2025. To read the full post click the links.

That Earth is round was well known long before Columbus

Super fact 28: That Earth is round, or spherical (or closely spherical) had been known for at least a couple of thousand years by the time Columbus set sail. Columbus did not set sail to prove that earth was round, and he knew it was round.

I’ve realized that this comes as a surprise to some. To read the post click here.

The earth globe showing the side with the Pacific Ocean. The Pacific Ocean covers most of this side. | Ten Selected 2025 Super Facts — Columbus thought earth was smaller. He did not know about the Pacific Ocean. Earth Pacific Ocean view Stock Illustration ID: 1617553012 by Matis75

EV Cars Indeed Emit Less Carbon Pollution

Super fact 29: EV Cars emit less pollution than Internal Combustion Engine, even considering manufacturing, disposal and EV Cars being charged by dirty grids.

There is a lot of misinformation about EVs including that EVs are not better for the environment. To read the post click here.

The histogram graph show that if you consider construction of facilities, manufacturing of vehicle and battery, production of fuel, vehicle operation as well as disposal the total average greenhouse gas emissions from EV cars is 52% less. — Lifecycle greenhouse gas emissions comparison of average gasoline car and 300 mile range EV. Feedstock and fuel include the generation of electricity for EVs.

Scientists Agree that Global Warming is happening and that we are the Cause

Super fact 34: Climate Scientists agree that Global Warming or if you call it Climate Change is happening, and that it is caused by us primarily because of our burning of fossil fuels. There is a long-standing scientific consensus on these two facts because the evidence is conclusive. Typically, studies show an agreement of at least 97% or 98% among climate scientists.

Polls show that most American are unaware of the consensus among climate scientists. To read the post click here.

There is almost total agreement among climate scientists that global warming, or climate change, is happening and is caused by us. To understand why, you need to know a little bit about the impressive evidence, which for all practical purposes is conclusive. Take a look at this post “Global Warming is Happening and is Caused by us”

The green graph is going up slightly starting from 46% in 2009 and ending in 58% in 2023. The black graph starts at 33% in 2009 and ends in 22% in 2023. The yellow graph starts at 2% in 2009 and ends in 2% in 2023. — The green graph corresponds to “most scientists think global warming is happening (%).” The black graph corresponds to “there is a lot of disagreement among scientists (%)”. The yellow graph corresponds to “Most scientists think global warming is NOT happening (%)”. Graph taken from the Yale Program on Climate Change Communication.

Time Dilation Goes Both Ways

Super fact 38 : If two observers are moving compared to each other both will observe the other’s time as being slower. In other words, both observers will observe the other’s clocks as ticking slower. Time slowing down is referred to as Time Dilation.

Clocks slow down as you travel at high speeds. However, the person travelling think they are standing still. It is the other person who is travelling. This is confusing. To understand it click here.

The picture shows two people Alan and Amy. Alan is on the ground. Amy is flying by Alan in a rocket speeding left. Both Alan and Amy are pointing lasers to the left. | Ten Selected 2025 Super Facts — In this picture Amy is traveling past Alan in a rocket. Both have a laser. Both measure the speed of both laser beams to be c = 299,792,458 meters per second. The speed of light is a universal constant.

Emissions of ozone-depleting gases have fallen by 99 Percent

Super fact 41 : Largely thanks to the Montreal Protocol in 1987 the emissions of ozone-depleting gases have fallen by more than 99%, 99.7% to be exact, according to Our World in Data. This has resulted in halting the expansion of the ozone holes and the reduction in emissions of ozone-depleting gases is saving millions of lives every year.

A gigantic victory for the environment that few are aware of. To read the post click here.

Gases visualized in the diagram are CFCs, Halons, HCFCs, Carbon Tetrachloride, Methyl Bromide, Methyl Chloroform. The diagram shows a peak around the end of 1980’s. — The phase out of six ozone depleting gases. Data source UN Environment Program (2023).

Sulfur dioxide pollution has fallen by 95 percent in the US

Super fact 44 : Sulfur dioxide pollution in the US has fallen by approximately 95% since the 1970s. This significant reduction is primarily due to regulations like the Clean Air Act. Global sulfur dioxide pollution has also fallen but not as much.

Another big victory for the environment that we seldom hear of. To read the post click here.

The graph shows a steep increase towards the end of the 19th century with a peak in 1973, followed by a steep decline. — US sulfur dioxide pollution since 1800. Data Source: Hoesly et al (2024) – Community Emissions Data System (CEDS). This graph is taken this page in Our World In Data. US Emissions peaked in 1973.

I should mention that by clicking this link you can visit the graph above Our World in Data and select different countries and regions and play around with the settings.

We Exploded Thousands of Nuclear Bombs

Super fact 48 : Since 1945 we have set off more than 2,000 Nuclear Bombs corresponding to a yield of an estimated 42,000 times that of the Hiroshima Bomb.

That we have exploded these many nuclear bombs was a surprise to me and perhaps to you too. To read the post click here.

Russian Tsar Bomba mushroom cloud rising high above the clouds. High quality photo realist ( 3d make ). | Ten Selected 2025 Super Facts — This is an illustration of the Tsar Bomba explosion by by mbafai Shutterstock Asset id: 2208486661. To see a photo of the actual Tsar Bomba explosion click here (it is copyrighted).

The Euler Number Math Magic

Super fact 53 : The Euler number denoted e, is an irrational number, which like the number pi is extremely important in mathematics. In addition, the relationship between the Euler number and pi; seemingly unrelated numbers, is quite amazing, especially if you throw the imaginary number: i = square root of -1 into the mix. Euler’s formula e^ix = cos(x) + isin(x), where x is degrees expressed in radians, is mind blowing to say the least. Radians means that 180 degrees is replaced by pi, and 90 degrees is replaced by pi/2, etc. A simpler special case, but equally amazing is Euler’s identity e^ix = -1, or e^ix + 1 =0. This is amazing math assuming you understand it.

One of the most amazing math facts explained. To read the post click here.

The formula e^ix + 1 =0 shown on a blue and black background. | Ten Selected 2025 Super Facts — Euler’s formula in cyber space with grid 3d illustration, Asset id: 1636161301 by Giggle2000

The Bermuda Triangle the Big Non-Mystery

Super fact 56 : The Bermuda Triangle mystery is a myth. There is not a higher risk of disappearances in the Bermuda Triangle. To be specific, disappearances do not occur in the so-called Bermuda Triangle, or Devils Triangle, with any higher frequency than in other comparable regions of the ocean. The “mystery” of the Bermuda Triangle is largely a manufactured one, perpetuated by sensationalized accounts that often misrepresent the facts and downplay the role of natural hazards like storms.

A surprise to the people who are convinced that there really is a mystery. To read the post click here.

The Bermuda triangle has one corner in Bermuda, one in Puerto Rico and one around Miami, Florida. — The Bermuda Triangle: It is approximately defined as a triangle Florida, Bermuda, and Puerto Rico. There is no exact definition. Alphaiosderivative work: -Majestic-, Public domain, via Wikimedia Commons.

Evolution is a Fact

Super fact 63 : Evolution is both a fact and a scientific theory. It is a fact that life has changed over time. This is supported by overwhelming evidence, while the theory of evolution provides a comprehensive scientific explanation for these changes, using processes like natural selection.

Yes, there are scientific facts, and that evolution is happening is an observed scientific fact. To read the post click here.

A photo of a trilobite fossil. | Ten Selected 2025 Super Facts — The fossil record is a lot more solid and much less problematic than the creationist books I have read claimed. Shutter Stock Photo ID: 1323000239 by Alizada Studios

Happy New Year to You All

To see the other Super Facts click here

US National Debt is Ballooning

Super fact 76 : The current US national debt is a record 38.35 trillion dollars and growing despite it being peacetime and no recession. The expected GDP for 2025 is 30.6 trillion, which corresponds to a debt to GDP Ratio of 125 percent.

The federal government needs to borrow money to pay its bills when its ongoing spending activities and investments cannot be funded by federal revenues alone. That the national debt is growing in terms of dollars may not be shocking. There is inflation, the country is growing, and as the economy grows its ability to pay the debt increases. Therefore, the debt to GDP Ratio is a better measurement of the size of the problem as this metric relates to our ability to pay the debt back. When the debt to GDP Ratio is growing there is a real problem.

Wars and recessions tend to add to the federal debt. While debt spikes during crises, it historically receded after. The second World War is an example (see below). However, since 1980 US debt has grown without seeming to come back down. Not only does the current debt to GDP Ratio exceed the one after the Second World War, the current trends show persistent deficits even in peacetime, unlike post-WWII, making the long-term outlook scary.

The graph shows two graphs, the US gross public debt and the net public debt as a debt to GDP Ratio. Both graphs show a spike during and after World War II followed by a recovery. Since 1980 the debt started growing again reaching higher than ever levels. — The top panel shows debt deflated to 2010 dollars; the second panel shows debt as a percentage of GDP. The US debt and the US debt to GDP Ratio is at a record high, exceeding that following the Second World War and we aren’t slowing down. Note the gross public debt includes all U.S. government debt, including money it owes itself (Social Security trust fund), while net public debt subtracts the government’s financial assets. The graph is from this Wikipedia article. en:User:O18, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons.

Below is an overview of the Federal Debt as percent of the GDP starting with 1965 to the beginning of 2025. The graph does not include most of the more than 2 trillion increases in debt during 2025, including a 1 trillion increase that happened in just two months toward the end of the year. So at the end there is a missing uptick. The graph below comes from this website.

In the past we used to discuss the national debt and the national deficit a lot, and it was viewed as an important and urgent problem to solve. It was a matter of intergenerational justice. There are some big problems that we have largely solved, for example, the sulfur dioxide pollution that created acid rain has fallen by 95 percent in the US, and the emissions of ozone-depleting gases have fallen by 99 Percent. As a result, we have mostly stopped talking about those problems. However, as the problem with national debt has grown, we have not increased but decreased our attention to the problem. The fact that the debt is now more than 38 trillion dollars, or $112,000 per person in US, and keeps rising despite no wars or recessions happening is probably a shock to many. It is true, it is an important fact, and it is surprising and perhaps shocking and therefore it is a super fact. To read more about the national debt click here.

Debt to GDP Presidents

One might be curious as to how the debt changed during specific Presidencies. I took the graph above and inserted lines representing the starting and ending years for the most recent Presidents. For example, Joe Biden’s Presidency started January 20, 2021, and ended January 20, 2025. I might not have gotten it exactly right so don’t read too much into it.

I added lines for Jimmy Carter, Ronald Reagan, H.W. Bush, Bill Clinton, George W. Bush, Barack Obama, Joe Biden, and Donald Trump. — I added the lines representing Presidents periods.

Below is a table I found online.

President	Years in Office	Debt-to-GDP at Start	Debt-to-GDP at End	Change (Percentage Points)
Franklin D. Roosevelt	1933–1945	~20%	~112.9%	+92.9 (WWII/Depression)
Harry S. Truman	1945–1953	112.9%	~67.1%	-45.8
Dwight D. Eisenhower	1953–1961	~67.1%	~55.2%	-11.9
Lyndon B. Johnson	1963–1969	~46.9%	~38.6%	-8.3
Jimmy Carter	1977–1981	~35.8%	~32.5%	-3.3
Ronald Reagan	1981–1989	~32.5%	~53.1%	+20.6
George H.W. Bush	1989–1993	~53.1%	~66.1%	+13.0
Bill Clinton	1993–2001	~66.1%	~56.4%	-9.7
George W. Bush	2001–2009	~56.4%	~84.2%	+27.8 (Wars/Recession)
Barack Obama	2009–2017	~84.2%	~103.6%	+19.4 (Great Recession aftermath)
Donald Trump	2017–2021	~103.6%	~132.8% (peak in Q2 2020)	+29.2 (Pandemic relief/tax cuts)
Joe Biden	2021–Present	~132.8% (at start of term, Q2 2020 peak)	~124.3% (as of 2024)	Fluctuation/slight decrease due to GDP recovery/inflation

Other Types of Debt

I should add that there are other types of debt not just federal debt / national debt (gross and net). American companies and financial institutions owe money and consumers have debt. As you can see in the graph below the debt to GDP ratio increase is true for those kinds of debts as well. We are a nation in debt. To read more about the graph below click here.

The graph shows four graphs representing Government (% of GDP) in purple, non-financial business sector-Debt (% of GDP) in red, Household - Debt (% of GDP) in blue, financial business sector (% of GDP) in green. — Debt as a percentage of GDP, United States, 1945 to 2020. Data source: US Federal Reserve, US Bureau of Economic Analysis (2020), tinyco.re/2448179 | Powered by ourWorldindata.org

To see the other Super Facts click here

Magnetars Super Magnets in the Sky

Super fact 75 : Magnetars are a type of neutron star with extremely powerful magnetic fields ranging from 10,000,000,000,000 Gauss to 1,000,000,000,000,000 Gauss. In comparison, Earth’s magnetic field varied from about 0.25 to 0.65 Gauss at the surface. In other words, the magnetar magnetic fields are from 20 or 40 Trillion times to 2 or 4 Quadrillion times stronger than Earth’s magnetic field at the surface.

A bluish neutron star surrounded by impressive looking fields | rs Super Magnets in the Sky — Magnetar – neutron star in deep space. For use with projects on science, research, and education. 3D illustration. Shutterstock Asset id: 1138434620 by Jurik Peter

The magnetic fields of magnetars are trillions of times stronger than the sun’s magnetic field, which is 1 Gauss on a quiet sun surface and 2,000 to 4,000 Gauss in sunspots. The magnetic field of an MRI’s machine is also incredibly strong (2,000 Gauss to 100,000 Gauss). It is thousands to over a hundred thousand times stronger than Earth’s magnetic field. That’s why you should not have metals around an MRI machine. However, the magnetic field of a magnetar is still hundreds of millions to tens of billions of times stronger than the magnetic field of an MRI machine, and the magnetic field is not confined to a small machine but surrounds a neutron star and stretches far out into space.

If you placed a magnetar halfway to the moon from Earth (a magnetar is around 12 miles in diameter), it would erase all the credit cards on Earth (see video below). If you get close to a Magnetar (1000 kilometers) cars and other metal would float up in the air and the atoms in yourbody would stretch into rods making organic chemistry impossible and kill you. If you placed a steel beam on the surface of a magnetar the magnetic field would pulverize it and destroy the atoms.

In 2004 a magnetar named SGR 1806-20 located 50,000 light years from our solar system (700 million times farther than the planet Jupiter) had a starquake disturbing the magnetic field and sending out a gamma burst that disrupted radio communication on Earth. I consider the existence of magnetars a super fact because the existence of these super magnetic monsters is shocking and not well known amongst the public, and yet their existence has been confirmed.

The picture shows a bright magnetar surrounded by a bluish gamma ray burst and it is all set to a background of stars. — On 27 December 2004, a burst of gamma rays from SGR 1806−20 passed through the Solar System (artist’s conception shown). The burst was so powerful that it had effects on Earth’s atmosphere, at a range of about 50,000 light-years. U Harvard, Public domain, via Wikimedia Commons.

What Are Neutron Stars and Magnetars?

A neutron star is the gravitationally collapsed core of a massive supergiant star. The collapse causes it to become super compact and relatively small by volume. As the name implies the atoms are crushed, and protons and electrons merge into neutrons, making the neutron star mostly neutrons. The typical diameter of a neutron star ranges from 10 to 25 km (6 to 15 miles) depending on its mass. Neutron star material is extremely dense.

A normal-sized matchbox containing neutron-star material would have a weight of approximately 3 billion tons, the same weight as a 0.5-cubic-kilometer chunk of the Earth (a cube with edges of about 800 meters) from Earth’s surface, or a very large mountain. In addition, the gravity on a neutron star is immense, about 100 billion to 200 billion times stronger than Earth’s gravity.

Magnetars are neutron stars with extremely powerful magnetic fields. They have the universe’s most powerful magnetic fields (trillions of times stronger than Earth’s) that power intense X-ray/gamma-ray bursts as its field decays, often seen as highly variable pulsars. They were first theorized in 1992 to explain Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). As of July 2021, 24 magnetars have been confirmed. According to the video below 30 magnetars have been confirmed in the Milky Way. There might be 3,000 in our Galaxy.

At top there is some text stating “A neutron star is a dense core left behind after a massive star goes supernova and explodes. Though only about 10 to 20 miles (15 to 30 kilometers) wide, they can have three times the mass of our Sun, making them some of the densest objects in the universe, second only to black holes. A teaspoon of neutron star material would weigh 4 billion tons on Earth. There are several types of neutron stars.” : Below the text at the top there is a picture of a magnetar, a pulsar and a magnetar plus pulsar. The text for each picture says: Magnetar - A magnetar is a neutron star with a particularly strong magnetic field, about 1,000 times stronger than a normal neutron star. That's about a trillion times stronger than a normal neutron star. That's about a trillion times stronger than Earth's magnetic field and about 100 million times stronger than the most powerful magnets ever made by humans. Scientists have only discovered about 30 magnetars so far. Pulsar - Most of the roughly 3,000 known neutron stars ae pulsars, which emit twin beams of radiation from their magnetic poles. Those poles may not be precisely aligned with the neutron star's rotation axis, so as the neutron star spins, the beams sweep across the sky, like beams from a lighthouse. To observers on Earth, this can make it look as though the pulsar's light is pulsing on and off. Magnetar + Pulsar – there are about six known neutron stars that are both pulsars and magnetars. | Super Magnets in the Sky — Courtesy NASA/JPL-Caltech, Attribution, via Wikimedia Commons

Magnetar YouTube Video

Other extreme stellar objects

I wish all of you Happy Holidays and Happy New Year

To see the other Super Facts click here

The Second Law of Thermodynamics Does Not Contradict Evolution

Super fact 73 : The second law of thermodynamics, or the fact that entropy is always increasing in an isolated system does not contradict evolution. Life is not a closed system. The environment is providing energy, the sun is providing energy, geological forces are providing energy, etc.

A lot of people have never heard of the second law of thermodynamics, or entropy and are unaware of the claim that the second law of thermodynamics contradicts evolution. So how can debunking this claim be surprising, and a super fact? The reason is that this is a popular claim among creationists and according to this Gallup poll 40% of Americans believe in creationism. The fact that this popular but false claim is rooted in a very basic misunderstanding of the second law of thermodynamics and what entropy is makes it super fact.

In the past I’ve read many creationist books that make the claim that the second law of thermodynamics contradicts evolution. One of them was Scientific Creationism (1985) by Henry M. Morris (the father of modern creation science), where he stated that the second law of thermodynamics says that everything tends towards disorder, making evolutionary development (ordering) impossible. The Death of Evolution: Restoring Faith and Wonder in a World of Doubt by Jim Nelson Black, another book I read, and which I gave a one star review on Amazon, makes the same claim. I’ve also come across a lot of people making this claim.

The people who make the claim that the Second Law of Thermodynamics contradict evolution typically do not understand the second law of thermodynamics and do not know what entropy is. Despite that fact they see it as a powerful argument against evolution. I’ve even seen it used against highly respected physics professors who “believe in”, well accept the reality of evolution, by people who had no understanding of the second law of thermodynamics. At one point I even believed the claim myself. Then I studied physics, and well, oops, I was forced to admit that I had been bamboozled.

The Second Law of Thermodynamics

The Second Law of Thermodynamics states that the total entropy (disorder) of an isolated system always increases over time. This means that natural processes tend to move from order to disorder (within the isolated system). It should be noted that disorder is a popular but imperfect metaphor for entropy. Entropy is not the same thing as what people think of as disorder. In physics entropy refers to the logarithm of the number of microstates compatible with the system’s measurable macroscopic state. As molecules randomly arrange themselves into new macroscopic states, the number of possible microstates will increase.

It also means that heat will spontaneously flow from hotter to colder objects, but never the reverse. Another thing it means is that mechanical energy can be converted to thermal energy, but never the reverse. It turns out that those seemingly different statements are physically identical.

Second law of thermodynamics. S corresponds to entropy. Ludwig Boltzman’s formula from 1874 — Second law of thermodynamics. S corresponds to entropy. Shutter Stock Vector ID: 2342031619 by Sasha701

It is very possible that the entropy of an organism is lower compared to a blob corresponding to all its molecules randomly distributed within a blob. However, that organism did not evolve in isolation inside a hermetically enclosed box without any energy from the outside. Life and evolution operate in an environment full of energy coming from the sun, the Earth, winds, oceans, geological forces, radiation, etc. Evolution does not take place in an isolated system.

It is also important to understand that within an isolated system, pockets of lower entropy can form if they are offset by increased entropy elsewhere within the system. That’s what the word “total” in total entropy means. Crystal formation is an example of creating local pockets of lower entropy (less “disorder”) within a system, but this is always accompanied by a greater increase in entropy in the surroundings. The Universe is an isolated system so the entropy within the Universe should always increase, but again the local pockets of lower entropy that evolution may create are accompanied by a greater increase of entropy elsewhere.

Crystal structure. This is model of a unique arrangement of atoms in a crystal. — Atoms in a crystal. The crystal represents a pocket of lower entropy. As this pocket of lower entropy forms there is equal of greater increase in entropy in the surroundings. What is true for the crystal is true for the molecules in living beings. Neither the formation of crystals nor the evolution of life contradicts the second law of thermodynamics. Asset id: 689181712 by BK_graphic.

Below is a YouTube video explaining how the second law of thermodynamics does not contradict evolution.

Entropy – Arrow of time

An interesting aspect of the second law of thermodynamics is that it makes entropy serve as an arrow of time. In general, the fundamental laws of physics are time reversible. The equations work the same forwards and backward in time. The equations for gravity, electromagnetism, and the strong nuclear force work the same regardless of time’s direction. An example is if you filmed a planet orbiting a star and played it backward, it would still follow the laws of motion the same way.

Throw a bunch of billiard balls on the floor and film them bouncing and hitting each other and the walls. If you then run the film backwards and forwards it would be far from obvious which is forward and which is backwards, except for the fact that the balls will slow down due to friction. However, balls slowing down due to friction is mechanical energy turning into heat, which is an example of the second law of thermodynamics. The fundamental laws of physics are time reversible, but the second law of thermodynamics is a notable exception. Entropy always increases in an isolated system (like the Universe). By measuring entropy, you can distinguish the past from the future, giving time a direction

Another evolution related post is: Evolution is a fact

To see the other Super Facts click here

Oxygen Blue Sky and Complex Life Exist Because of a Bacteria

Super fact 72 : About three billion years ago Cyanobacteria evolved a new type of photosynthesis that used sunlight, water, and carbon dioxide to create energy, while releasing oxygen as a waste product. This transformed the atmosphere and enabled complex life by allowing aerobic respiration to evolve. This invention turned the sky blue, gave us the protective ozone layer, but also caused climate change resulting in massive extinctions.

A microscopic photo of Cyanobacteria. They look like green blobs with small nucleuses. | Oxygen Blue Sky and Complex Life Exist Because of a Bacteria — An example of a Cyanobacteria. From Wikipedia. Luke Thompson from Chisholm Lab and Nikki Watson from Whitehead, MIT, CC0, via Wikimedia Commons

Cyanobacteria, also known as blue-green algae, are bacteria capable of oxygenic photosynthesis. Between 3.4 and 2.5 billion years ago they developed a new and very effective form of photosynthesis, which took advantage of highly abundant resources, using sunlight, water, and carbon dioxide turning it into sugar and releasing oxygen as byproduct. This is referred to as the Great Oxidation Event. You can read more about this event here, here, here, here, here, or in the book Becoming Earth by Ferris Jabr.

The atmosphere prior to the Great Oxidation Event was primarily composed of volcanic gases including nitrogen, carbon dioxide, water vapor, methane and ammonia, but almost no free oxygen. The Great Oxidation Event changed all this, but it likely took at least 200 million years.

Labeled educational bacteria internal structure scheme. — Cyanobacteria vector illustration. Biological blue green algae diagram with carboxysome, thylakoid and phycobilisome parts location inside cell. Asset id: 1687712761 by VectorMine

A Microbial Great Extinction and Snowball Earth

Oxygen was a toxic gas to many early microbes forcing them to adapt or perish. In addition, the change in the atmospheres composition changed the climate, resulting in a severe global cooling referred to as Snowball Earth. This caused a great extinction, perhaps the most severe extinction in Earth’s history. It is not included among the five mass extinction events in Earth’s history because it happened very early in Earth’s history when only primitive microbial life existed and fossil evidence from that time is nearly non-existent. The definition of a mass extinction event is that at least 75% of the world’s species are lost during a short period of time – geologically speaking. This period is not clearly defined but often defined to be two million years. It is very difficult to determine whether the great extinction following the Great Oxidation Event qualifies as a mass extinction event. To read about mass extinctions click here.

Ancient Earth almost entirely covered by ice and white snow. | Oxygen Blue Sky and Complex Life Exist Because of a Bacteria — Proterozoic era in the history of the Earth. Snowball earth. Global glaciation of the Earth. Asset id: 2010272753 by Elena Kelman

The Ozone Layer and the Blue Sky

Oxygen is also responsible for formation of the ozone layer in the atmosphere. The UV radiation from the sun split oxygen molecules, which consist of two oxygen atoms, into two separate atoms of oxygen, which then reacted with another oxygen molecule to generate ozone, and oxygen molecule consisting of three oxygen atoms. Ozone acts as a natural sunscreen to prevent harmful UV radiation from reaching the earth. Therefore, oxygen not only enables land dwelling complex multicell organisms to exist by allowing aerobic respiration to evolve, but also by protecting life from too much UV radiation.

As mentioned above, the atmosphere prior to the Great Oxidation Event was primarily composed of volcanic gases and almost no free oxygen. The color of the sky was likely orange, brown. As oxygen replaced the existing gases the sky slowly turned blue. Oxygen molecules along with Nitrogen molecules scatter blue light from the sun through a process called Rayleigh scattering, making the sky appear blue.

Cyanobacteria and The Great Oxygenation Event

It should be noted that there were other geological and biological processes that were responsible for this permanent shift in the Earth’s system, including changes in the composition of volcanic emissions and chemical reactions that allowed atmospheric hydrogen to escape to space, leaving behind an excess of oxygen molecules. However, whatever the exact mix of mechanisms, cyanobacteria were undoubtedly a critical source of accumulating oxygen. It is possible that tectonic activity altered the cycling and distribution of phosphorus and other nutrients essential for cyanobacteria. To read more see the book Becoming Earth by Ferris Jabr.