Tag: Surprising fact

The Pole-Barn Paradox and Solution

Super fact 39 : Relativistic length contraction goes both ways. If two observers are moving compared to each other both will observe the length of the objects in the other’s system to be shorter in the direction of motion. The first observer will think that a yard stick in the second observer’s frame will be shorter whilst the second observer will think that the yard stick in the first observer’s frame is the shorter one.

Assume a pole and a barn are of equal length when both objects are stationary. If the pole is moving (at a high speed) compared to the barn, then the pole will be shorter than the barn from the barn’s perspective but longer than the barn from the pole’s perspective. Does the pole fit inside the barn or not? This is referred to as the pole-barn paradox, or the barn-door paradox, or the ladder paradox (if a ladder is used instead of a pole).

I call this conundrum a super fact because whilst most people have heard of relativistic time dilation and perhaps length contraction, the fact that it goes both ways comes as a surprising head scratcher. The situation is analogous to my super fact post “Time Dilation Goes Both Ways” where I state:

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. And this post is about how time dilation goes both ways.

Both the time dilation paradox and the pole-barn paradox are solved by the non-simultaneity in relativity. However, the pole-barn paradox is more concrete and perhaps more in your face. You can easily imagine the problematic paradox.

A picture of a girl, Amy who is speeding past a man, Alan and his barn. Amy has a pole. The pole is contracted along the direction of motion from Alan’s perspective and the barn is shorter along the direction of motion from Amy’s perspective | The Pole-Barn Paradox and Solution
Amy is speeding past Alan and his barn at a high speed. Amy has a pole. Because of the high-speed Amy’s pole appears shortened and will easily fit in Alan’s barn. However, to Amy it is Alan’s barn that is contracted, and her pole has the normal length and will therefore not fit in Alan’s barn.

Postulates of Special Relativity

The two postulates of special relativity are:

  • The laws of physics are the same in all inertial frames of reference. An inertial frame is a system that moves at a constant velocity.
  • The speed of light in a vacuum is constant for all observers, regardless of the motion of the light source.

The first postulate is called the principle of relativity and goes all the way back to Galileo Galilei. It means that no experiment can determine whether you are at rest or moving at a constant velocity. The reciprocity of length contraction follows from this postulate. If the length of the pole in the example above is half as long as the barn in both the barn frame and the pole frame then you could tell who was standing still and who was moving from that fact, and that violates the first postulate. The first postulate demands that if the pole is half as long in the barn frame and that the barn is half as long in the pole frame.

The second postulate is the more shocking one and is special to relativity. It was discovered experimentally at the end of the 19th century but was too difficult for scientists to accept at first so various ad hoc explanations were put forth to explain it away, until the theories of relativity were created. I designated this postulate as my super fact #4 and you can read about it here.

Length Contraction

Time dilation means that a time interval between two events in a certain frame is longer by a factor B in a frame moving relative to the first frame (see picture below). Let’s imagine Amy moving at the speed v compared to Alan and his barn. Amy passes the left side of the barn at a certain time and soon after the right side. The time difference from Alan’s perspective is T and the width of the barn is L, so L = vT. From Amy’s perspective the time difference is T’ and width of the barn L’ and L’ = vT’. We denote Amy’s measurements with a prime. Note the velocity must be the same in both systems. However, Amy’s clock ticks slower (from Alan’s perspective) so T’ = BT or T = T’/B (time dilation). So, L’ = vT’ = vT/B = L/B.

If the derivation of the formulas above is confusing to you, ignore the math, and just remember that Alan measures a shorter time for the passing of the pole (because Amy’s clock is slower) from his perspective and therefore the pole must be shorter as measured from his system. If Alan measures two seconds for the passing of the pole than Amy measures maybe four seconds. It is Amy’s pole, so her longer measurement corresponds to the proper length of the pole whilst Alan’s measurement is the contracted length. Note the length contraction can only happen along the direction of motion, not perpendicular to it. To read more about length contraction click here.

This picture shows the formula for time dilation, the expression for the beta factor, and the formula for length contraction | The Pole-Barn Paradox and Solution
The beta factor used in the formula for time dilation as well as length contraction.

Solution to the Pole-Barn Paradox

So, Amy’s pole cannot fit in Alan’s barn. The pole is moving fast so it must move in and out of the barn. Now let’s create the paradox. Imagine the barn having doors on each side that open for the moving pole and then close for a moment to entrap the pole and then they open as the pole leaves the barn. Here is the paradox, if they open and close at the same time, than the pole can be inside the barn (entrapped) from Alan’s perspective but not from Amy’s perspective. From Amy’s perspective the pole does not fit.

However, the solution to the paradox lies in “open and close at the same time”. If the doors open and close at the same time from Alan’s perspective, then they don’t open and close at the same time from Amy’s perspective.

From Amy’s perspective the door on the left side will open first and let the pole in and then after that the right door will open. After the pole has fully entered the barn and some of it is sticking out on the right-hand side then the left door will close but the door on the right will remain open  until the pole is entirely outside. Relativistic non-simultaneity solves the paradox.

A picture of a girl, Amy who is speeding past a man, Alan and his barn. Amy has a pole. The pole is contracted along the direction of motion from Alan’s perspective and the barn is shorter along the direction of motion from Amy’s perspective. There are two doors on each side of the barn. In Amy’s world the left door is open letting the pole into the barn, whilst the right door is closed. In Alan’s world both doors are close thus enclosing his shorter pole.
In Alan’s frame the doors can be closed at the same time and enclose Amy’s pole. In Amy’s frame the doors open and close to let the pole through but they don’t open and close at the same time.

Finally, below is a YouTube video that explains and solves the pole-barn / barn-door / ladder paradox simply and efficiently in a little over two minutes.

Book Recommendations on Relativity

To see the other Super Facts click here

There is strong evidence for the Big Bang

Super fact 37: There is strong evidence for the Big Bang, and we know a lot about how the Universe evolved through time since the Big Bang.

Considering the evidence that has accumulated throughout the years for the Big Bang it is hard to deny it happened. In my experience very few people are aware of this evidence, and they are surprised to find out how much evidence there is and how many details we know about the evolution of the universe. It is easy to believe that scientists are guessing when you don’t know much about the evidence yourself. But they are not guessing. That is why I call this a super fact.

In addition, there’s a lot of misconceptions around the Big Bang as well surprising facts. A few additional things that might surprise people are that the Big Bang was not like an explosion, the Universe did not expand into something. In addition, there might be multiverses and multiple Big Bangs, and there are cyclic models, and so-called eternal inflation. There are things we know and things we don’t know.

The pictures show an expanding Universe starting with quantum fluctuations followed by inflation, then an afterglow light pattern 375,000 after the Big Bang and then the so-called dark ages, the creation of stars and galaxies | There is strong evidence for the Big Bang
This file is in the public domain in the United States because it was solely created by NASA. (from Wikimedia commons

The Expansion of the Universe

It used to be believed that the Universe was static. In 1929 the astronomer Edwin Hubble discovered that the universe was expanding. He made this observation by analyzing the light from distant galaxies and noticing that their light was redshifted. I am going to explain what that means next.

Light emitted from elements, atoms and molecules have light absorption patterns that are unique to the atom/element in question. This is called a light spectrum. This makes it possible to identify the elements in a star and their proportions. Red shifted means that the absorption lines have moved towards red because the frequency of the light has been shifted due to the motion. This is called the doppler effect.

You can notice this phenomenon for the case of sound when an ambulance is coming towards you and then speeding by you. The sound changes. Hubble was using the redshift to the determine that further away the galaxy was the faster it was moving away from us.

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.

A natural explanation for this is that the universe is expanding, and that it once must have been much more compressed, but it is not the only explanation. However, there is more evidence.

The Cosmic Microwave Background Radiation

If you assume that the universe once was much more compact and much hotter than today, particles such as protons, neutrons and electrons would have been free and close together preventing light from freely moving around. However, as the universe kept expanding and cooling these particles eventually should have been able to form atoms allowing light or electromagnetic radiation to freely move around.

Some physicists, Alpher, Herman and Gamow predicted around 1950 that this should have left behind a detectable microwave background radiation. This radiation was detected by chance in 1964 by two physicists, Penzias and Wilson. This radiation had the expected properties and careful study of this Cosmic Microwave Background Radiation (CMBR or CMB) has given us a lot of information about our universe and may give us information about other universes (multiverses).

Its existence is strong evidence that the universe once was very compressed and much hotter, i.e., the Big Bang. An interesting fact is that in old TVs, between the channels (old people will remember this), you had this fuzz, or war of the ants as some people called it, and part of that TV fuzz is the CMBR.

A big sky map with varying colors, yellow, red, green and blue | There is strong evidence for the Big Bang
This is a sky map of the cosmic background radiation from when the universe was around 380,000 years old. It was created with the help of satellite (NASA) measurements. The colors are artificial and show tiny temperature variations. NASA / WMAP Science Team, Public domain, via Wikimedia Commons.

You can watch a 4-minute video about the discovery of the CMBR narrated by Neil DeGrass Tyson on this PBS web page by clicking here.

Abundances of Light Elements

Yet another piece of evidence is the relative abundance of hydrogen and helium compared to heavier elements. The physics at the beginning of the Universe under the Big Bang tells us that initially regular matter should have consisted of 75% hydrogen and 25% helium and hardly anything else, and that is composition the oldest stars had when they were new. In addition, the oldest stars we’ve found appear to have an age just under the 13.8 billion years that we get for our Universe assuming the Big Bang theory (that’s another piece of evidence).

The picture consists of two pie chart graphs representing stars. The left one is a first-generation star with one pie for the 75% hydrogen and one pie for the 25% helium.
The first-generation stars consisted of 75% hydrogen and 25% helium and trace amounts of Lithium. A second or third generation star like our sun is still mostly hydrogen and helium but also many other elements. The rocky planets circling the sun are mainly elements heavier than hydrogen and helium. Image credit NASA, ESA, CSA, STScI

A Very Brief History of Time

So, it all started with a quantum fluctuation. The first 0.000000000000000000000000000000001 seconds is called the inflationary period characterized by super-fast expansion, much faster than the speed of light, as we know it today. At this time the strong nuclear force becomes distinct from the weak nuclear force.

I should point out that during the first 0.0000000000001 seconds the physics laws may not have applied in a normal sense. I should also point out that this was not an explosion. An explosion explodes into something but there was nothing else outside of the universe, so this is more like superfast growth.

At a fraction of a second protons and neutrons form from quarks and after one second neutrinos came into existence and if primordial black holes exist, they were formed at this time too. After two minutes nucleus consisting of neutrons and protons are formed, and the first elements hydrogen and helium formed. After 20 minutes an opaque hot plasma forms, after 100,000 years neutral helium atoms form, and after 375,000 years CMBR is created, etc.

This is just a small sample of everything that we know happened after the Big Bang, based on the known laws of physics. You can read about all the details in books like The First Three Minutes by Steven Weinberg or A Brief History of Time by Stephen Hawking.

vector illustration of up and down quarks in proton and neutron on white background. The proton (left) is a red and blue up quark and a green down quark. The neutron is a red and green down quark and a blue up quark | There is strong evidence for the Big Bang
The proton and neutron each consist of three quarks. They are formed at a fraction of a second after the Big Bang. Asset id: 2333679305 by KRPD.

Pre–Big Bang Cosmology

So, what was there before the Big Bang, if anything? Well, that part is speculation, but there are many good ideas. A popular hypothesis speaks of quantum fluctuations setting off the Big Bang. There are models in which the whole of spacetime is finite, including the Hartle–Hawking no-boundary condition. This means that time itself came into existence with the Big Bang and therefore nothing could have preceded it. This means that the Big Bang could not have been caused or created by anything else, just like a universe that has existed eternally could not have been caused or created by anything else.

In a sense, despite being 13.8 billion years old, the universe in this scenario would have always existed. Because the concept of “always” stops at 13.8 billion years ago. Stephen Hawking used the analogy of the north pole. You can’t go further north from the north pole.

There are other models that include multiverses, for example, eternal inflation, in which universal inflation ends locally here and there in a random fashion, each endpoint leading to a bubble universe, expanding from its own big bang. You can view this model as inflation being the river of time with the various universes popping up like bubbles in the stream.

In another model inflation is due to the movement of branes in string theory and Big Bangs are the result of colliding branes. There are cyclical models, such as Nobel Prize winner Roger Penrose’s Conformal cyclic cosmology in which one universe gives rise to another universe as it dies.

Notice that Pre-Big Bang Cosmology is speculative, but the reality of the Big Bang is backed by strong evidence.

Thousands of universes represented as colorful balls | There is strong evidence for the Big Bang
The surface of a multiverse with a lot of universes 3d rendering Asset id: 2256998119 by Dr. Norbert Lange.

To see the other Super Facts click here

Every Symmetry is Associated with a Conservation Law

Super fact 36: Every continuous symmetry of the action of a physical system with conservative forces has a corresponding conservation law. This revolutionary insight was mathematically proven in 1915 by a relatively unknown woman, Emily Noether.

It is not easy to understand what this super fact means, and therefore it is easy to miss the fact it says something fundamental about the nature of reality. It says something profound about our Universe and all possible Universes. It is arguably one of the most profound discoveries in science. Since the discovery of Noether theorem, we do physics differently and we view our physical reality differently.

In the book “The Theory of Almost Everything” the author, theoretical physicist Robert Oerter states that the standard model of elementary particles, or most of modern physics, rests on three pillars, special relativity, quantum physics, and Noether’s theorem. Which one of those three have you not heard of? I guess Noether’s theorem.

That question brings me to the second part of the super fact. Emily Noether did a lot for mathematics and physics in addition to her first theorem (stated above), and yet she is not well known. Albert Einstein said of Emily Noether : “Fräulein Noether was the most significant creative mathematical genius thus far produced since the higher education of women began”. Notice he didn’t say “woman genius”.

Why I consider Noether’s (first) theorem a super fact is because it tells us something fundamental about reality that is highly surprising and yet undisputable (mathematically proven) and not many of us know about it. The second part of the super fact, that despite being one of the greatest geniuses of the 20th century she is so unknown, is also surprising.

A young woman in Victorian clothing sitting at a small table.
This picture reminded me of Emily Noether a genius and one of the greatest mathematicians in human history. This is a submission for Kevin’s No Theme Thursday.

Noether’s Theorem What Does It Mean

Noether’s theorem, says that symmetries in the universe give rise to mathematical conservation laws. One way to understand this is by using an example. That the physical laws remain the same as you translate a system in time is an example of a continuous symmetry.

If you do an experiment twice at two different times, let’s say at 8:00AM and at 9:00AM, and everything is set perfectly identical both times you are likely to get the same result. Well barring statistical/quantum uncertainty. The point is that the physical laws did not change. If the physical laws do not change between 8:00AM and 9:00AM, then you have a continuous symmetry.

Noether’s theorem says that if you have a continuous symmetry, you also have a conservation law, and the conservation law in this case is the conservation of energy/mass. If the physical laws do not change between 8:00AM and 9:00AM then mathematically the total energy / mass of the closed system must remain constant.

It follows that energy is not destroyed or increased. At first it seems like the time symmetry and energy/mass conservation have nothing to do with each other, but the symmetry gives rise to the conservation law. So, if you ask the question, why is energy / mass conserved, the answer is because physical laws don’t change with time.

There are many symmetry-conservation law pairs in nature. Translational symmetry, the fact that the laws of physics stay the same if you move to the side or forward, results in the conservation of momentum. The symmetry of laws that does not change if moving around in a circle amount to the law of conservation of angular momentum. Other symmetries result in the conservation of charge.

The converse is also true. If you find that a quantity is conserved you can find a symmetry, and if you find a symmetry that is broken you can find a quantity that is not conserved after all. There is not much in science that is more fundamental than that and in addition Noether’s theorem is very useful.

The picture illustrates the collision of two balls. It features mathematics demonstrating that linear momentum (mass times velocity) is preserved | Every Symmetry is Associated with a Conservation Law
If the physical laws stay the same when translated in space then linear momentum is conserved. Conservation of momentum principle in isolated system Asset id: 2319593529 by MZinchenko.

Emily Noether

Emily Noether was born into a Jewish family in Germany March 23 in 1882. She was the daughter of the mathematician Max Noether. She studied mathematics and completed her doctorate in 1907. At the time, women were largely excluded from academic positions, but she worked at the Mathematical Institute of Erlangen without pay for seven years. She eventually gained paid positions. She made huge contributions to abstract algebra, calculus of variations, topology and other mathematical fields.

Her most important contributions are the Noether’s theorems, the first one described here. When Hitler came to power in 1933, she had to flee Germany. She got a position as a professor at Bryn Mawr in 1933. She died in 1935.

Black and white photo of Emily Noether wearing a white shirt, a darker skirt and a black bowtie.
Emily Noether in 1910. Unknown author Unknown author Publisher: Mathematical Association of America [3], Brooklyn Museum [4], Agnes Scott College [5], [6], Public domain, via Wikimedia Commons.

Concluding Summary

Noether’s Theorem changes how we view the Universe and the laws of physics. For example, the conservation of energy is not just something we empirically discovered. It follows mathematically from physical laws not changing by time. It represents a paradigm shift in science that arguably is as important as quantum mechanics or relativity and yet very few people have heard of it. I find that quite shocking.

To see the other Super Facts click here

Natural Disasters Kill Less People Now Than 100 Years Ago

Super fact 35: Natural disasters kill a lot less people now compared to 100 years ago. That is despite a larger population and despite the fact that climate change has increased the frequency and intensity of many types of natural disasters.

This is a super fact because surveys, such as this questionnaire from Gap Minder, show that the vast majority of the public (90%) believe that deaths from natural disasters have increased or stayed the same. Gap Minder is a Swedish highly respected non-profit founded by Hans Rosling that promotes increased use and understanding of statistics. Our World in Data (OWID), a renowned scientific online publication focusing on large global problems largely took its inspiration for Gap Minder and Hans Rosling.

The reason for the fewer deaths from natural disasters is not that there are fewer natural disasters, on the contrary, it is because we are now much better at predicting, handling and recovering from natural disasters. Our warnings systems, rescue systems and healthcare have improved significantly.

The graphics in this article from BBC show that the frequency of natural disasters has increased, and that the cost of natural disasters has increased, and yet the number of deaths has decreased.

The graph below comes from the Gap Minder article. It shows the annual deaths from natural disasters in ten-year intervals starting with 1930. In the 1930’s there were 971 thousand deaths per year from natural disasters and during the period 2010 to 2016 there were 72 thousand deaths per year from natural disasters, an improvement by more than 13 times.

However, it should be noted that there was a huge flood in China 1931 causing an estimated 3 million deaths, and it skews the numbers for the 1930’s interval.

Originally, I set the headline for this super fact to be “10 Times more people died from natural disasters a hundred years ago” but I changed it to “Natural Disasters Kill Less People Now Than 100 Years Ago” because I realized that the 1930’s peak is an outlier because of the 1931 flood. I don’t want my headlines to be click bait.

The graph shows 300 to 400 thousand annual deaths at the beginning of the 20th century, then 971 thousand annual deaths in the 1930’s, then it continuously gets lower until the annual deaths in the 2010 to 2016 period is 72 thousand deaths per year | Natural Disasters Kill Less People Now Than 100 Years Ago
This graph from the Gap Minder article shows the annual deaths from natural disasters in ten-year intervals starting with 1930. The trend is down.

This does not mean that we should not worry about the increase in frequency and intensity of natural disasters from climate change. First of all, there are no warning systems and healthcare available for Koalas and Elephants, secondly cost matters, and thirdly there is no guarantee that we can keep improving our ability of predicting, handling and recovering from natural disasters enough to match the accelerating risks for natural disasters.

What People Believe Regarding Disaster Deaths

The Gap Minder article above report on a question survey conducted by Gap Minder. They asked large groups of people in 14 countries the following multiple-choice question “How did the number of deaths per year from natural disasters change over the last hundred years?” The choices were:

  • A. More than doubled
  • B. Remained more or less the same
  • C. Decreased to less than half

Most people answered A, a lot

of people answered B, but only 10% got the correct answer C, decreased to less than half. In other words, if chimpanzees had answered this question by randomly picking an answer, they would have done better than people. This is why I consider this a super fact. Below is a graphics taken from the Gap Minder article that shows how people in different countries responded.

There are 16 bars divided into three colors, green for the correct answer – “decreased to less than half”, orange for “remained more or less the same”, and red for “more than doubled”. The 16 bars correspond to 14 countries, one for the average (10%), and one for random answers by chimpanzees (all 33.3%). The 14 countries are Finland, Norway, Japan, Sweden, UK, Australia, US, Spain, Canada, South Korea, Germany, Belgium, Hungary, and France | Natural Disasters Kill Less People Now Than 100 Years Ago
The histogram graphics above show the answers to the question “How did the number of deaths per year from natural disasters change over the last hundred years?” The correct answer “decreased to less than half” (in green) was rarely picked. The graphics is taken from the Gap Minder article mentioned.

EF3 Tornado in Dallas

In October 2019 an EF3 tornado ripped through our neighborhood. It left a 2-3 miles long trail of destruction. Roofs were lifted off houses, cars and buses were flown around, hundreds of houses were destroyed, bricks were flying around in the wind, trees were uprooted, and tree branches were flying around, and pieces of concrete crashed into buildings and hit steel fences so forcefully that it bent even quarter inch thick steel fences.

Unlike many of our neighbor’s houses, our house stood, but our chimney was smashed by a piece of concrete coming off a neighbor’s house, we had to replace our roof, our garage door, the wiring in the attic, our fence and my grill flew around in the yard. The amazing thing was that no one in the neighborhood died.

Why did no one die? Was it maybe because no one was outside walking the dog, or driving around, because everyone had received the alarm on their mobile phone about the approaching tornado and was therefore sheltering inside in a safe place? Imagine the same thing happening in the 1930’s.

Below are a few photos from that day and here are two links with more photos, link-1 , link-2. On the five-year anniversary of this event NBC news interviewed me about this event. To see the interview click here . My interview is at one minute and ten seconds.

A neighbor’s house with the roof ripped off after the EF3 Tornado in Texas.
NBC used this photo. A neighbor’s house the morning of October 21st, 2019. Again, click on the image, or here, to see the interview. My interview is at one minute and ten seconds.
The photo shows a severely damaged house and lots of debris consisting of wood and trees and tree branches after the EF3 Tornado in Texas.
Another neighbor’s house. This house was about 100 yards from our house. It took a direct hit from the tornado.
This photo shows a house that is completely destroyed after the EF3 Tornado in Texas | Natural Disasters Kill Less People Now Than 100 Years Ago
Another house in our neighborhood.

My wife Claudia asked me to go check on her parents. I drove about 50-100 yards when a neighbor’s roof lying across the road stopped me. I turned around but this time I was stopped by a large pile of trees lying across the street. So, I started walking, but this time I was stopped by a group of firemen telling me that it was too dangerous to be outside. They told me to go back home, and I did. The next day we were able to visit her parents and below is what we saw.

The photo shows my wife Claudia walking into a house with debris everywhere after the EF3 Tornado in Texas.
Inside my wife Claudia’s parents’ house. This was the morning after. In the photo we are walking into their house to check on them (that’s my wife).
To see the other Super Facts click here

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.

This is a super fact because surveys show that this is not what the public believes and yet it is true. The public incorrectly believes that there is a large disagreement among scientists on this topic. A note, to understand why the evidence is conclusive as to why global warming is happening and is caused by us click here.

Note : I will use the term “global warming” in this review. Whether you call the phenomenon climate change, climate disruption, or global heating, is not important.

The Scientific Consensus

This extensive survey from 2013 of 12,000 climate papers (papers published over two decades) by Dana Nuccitelli and Cook, etc., concluded that 97.1% of climate scientists endorsed the consensus position that humans are causing global warming.

They also did a science author self-rating which concluded that 97.2% of climate scientists endorsed the consensus position that humans are causing global warming. Another conclusion from the survey was that the consensus had increased from around 90%, perhaps less, in the early 1990’s.

A later review of six independent, peer-reviewed studies examining the scientific consensus about global warming have concluded that between 90% and 100% of climate scientists are convinced human-caused global warming is happening. A more recent study (2021) found that as many as 98% of climate scientists are convinced global warming is happening and is human-caused. Numerous other surveys have concluded the same thing.

People’s Beliefs About Global Warming

This 2024 survey from Yale University show that most Americans (61%) understand that global warming is mostly human caused. By contrast, 28% think it is caused mostly by natural changes in the environment. Most Americans (58%) <<Link-6>> understand that most scientists think global warming is happening. This percentage has trended generally upward since this survey began in 2008. By contrast, about one in five (22%) think there is a lot of disagreement among scientists about whether global warming is happening.

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

However, only one in five Americans (20%) understand that nearly all climate scientists (more than 90%) think that human-caused global warming is happening. The aforementioned Dana  Nuccitelli refers to this in his book Climatology versus Pseudoscience as the consensus gap. Again, this large discrepancy between public perception and reality makes the consensus gap a super fact. Research has shown that this discrepancy has a large impact on people’s other beliefs regarding global warming.

This is bar graph. It shows that 2% believe the answer is 0-10%, 2% believe the answer is 11-20%, 3% believe the answer is 21-30%, 3% believe the answer is 31-40%, 8% believe the answer is 41-50%, 7% believe the answer is 51-60%, 7% believe the answer is 61-70%, 13% believe the answer is 71-80%, 13% believe the answer is 81-90%, 20% believe the answer is 91-100%, 22% don’t know | Scientists Agree that Global Warming is happening and that we are the Cause
The question was, To the best of your knowledge what percentage of climate scientists think that human-caused global warming is happening? Graph taken from the Yale Program on Climate Change Communication.

Why is there a Consensus Gap?

In his book Climatology versus Pseudoscience Dana Nuccitelli explains that a relatively small group of so-called climate skeptics, or more accurately called climate contrarians have received a lot of attention from media. Even though their science is bad, and they’ve published their error ridden papers in obscure or discredited journals, and the fact that their predictions have failed repeatedly many times over, they have had an enormous influence on public discourse. Conservative politicians, and many talk show hosts are blindly devoted to their falsehoods, whilst real scientists are being attacked.

It is not just rightwing media who are using them for their purposes, but mainstream media are giving the contrarians undue attention as well. Sensationalism is one issue. A science contrarian claiming that all the climate scientists are wrong, and that he is the only one who finally got it right is a lot more interesting of a story than a repeat of the consensus. Another issue is false balance. Journalist should not feel that they must give equal time to evidence-based science and nonsense, but that is often the case. To read my review of this book click here.

The Oregon Petition

I am mentioning the Oregon petition because I fell for it myself. The Oregon petition was an official looking petition circulated by climate contrarians, claiming that there is no evidence that human-caused global warming will cause catastrophic heating of earth’s atmosphere and disruption of earth’s climate, and that adding more carbon dioxide to the atmosphere would even be beneficial for plants and animals. It got an impressive number of signatures, 32,000 after some years.

However, it turned out that the signatories rarely had climate expertise, and were not scientists, and the survey listed many falsified names such as the names of the Spice Girls and several fictional characters. Less than 200 of the signatories were climate researchers.

It was a con, but it was touted in a lot of media as the truth. I saw it over and over and I believed it. I was later surprised to learn that it was a con and that a scientific consensus existed on global warming / climate change. Learning that I had been bamboozled on this matter was one of the red flags that prompted me to start doing some fact checking on the issue global warming.

To see the other Super Facts click here