DinosaurTheory Introduction

Solution to the Puzzle

We begin our explanation of how dinosaurs and pterosaurs grew so large by reviewing a basic principle of physics: mass and weight are not the same thing. The mass of an object remains constant regardless of location, whereas weight is the product of mass and gravitational field strength.

If we excuse the mixing of metric and English units, a fairly large person with a mass of 100 kg weighs about 220 pounds (1,000 N) on Earth. If that same person could somehow stand on the surface of the Moon without a spacesuit, their mass would still be 100 kg, but because of the Moon’s weaker gravitational field, they would weigh only about 36 pounds (162 N).

When astronauts were on the Moon, they hopped about because they felt so light on their feet. This occurred because the Moon’s surface gravity is only about one-sixth that of Earth. If humans were to establish a permanent colony on the Moon and live there for thousands of years, future generations would likely evolve to be much larger than people on Earth. Eventually, such Moon-adapted humans would be unable to return to Earth because they would weigh too much to stand or walk in Earth’s stronger gravitational field.

In science-fiction films and television shows, space travelers cross the galaxy and land on distant planets where gravity is conveniently identical to Earth’s. In reality, this is unlikely, since there is usually considerable variation in the size of planets and moons. On larger planets, travelers would feel much heavier and struggle to move. On smaller planets or moons, they would feel extremely light and leap about with ease. They would also observe that animals on the larger planets – the strong-gravity worlds - tend to be smaller, while animals on weak-gravity worlds tend to be much larger. Although such creatures would appear either tiny or monstrous to us, their size would be completely normal for their environment.

Now consider how this applies to the enormous terrestrial animals of the Mesozoic era. The exceptional size of dinosaurs, pterosaurs, and birds implies that these animals lived in an environment with a much weaker effective gravity than exists on Earth today.

How could this be possible? Some people have proposed far-fetched ideas involving changes in Earth’s mass or the gravitational constant. However, it is not necessary to suspend reason or violate the laws of nature to explain how effective gravity could have been reduced. As already demonstrated on Earth’s surface, there are scientifically sound ways to decrease the effective weight of objects.

When we step on a bathroom scale, the weight we measure is slightly less than the force due solely to gravity. This is because two additional forces act in opposition to gravity: the centrifugal force from Earth’s rotation and the buoyant force from Earth’s atmosphere. Together, these make us feel about one or two pounds lighter.

The centrifugal force arises from Earth’s rotation and represents a weak tendency to fling objects away from the surface. It is given by:

F_c = m r ω²

where F_c is the centrifugal force, m is mass, r is distance from the axis of rotation, and ω is Earth’s angular velocity. The faster Earth spins, the greater this force becomes.

While Earth was rotating rather quickly when it first formed, its rotational speed has been slowing down ever since. During the Mesozoic era - billions of years after Earth first formed - its rotational speed had slowed considerably, yet it was still spinning faster than it does today. Thus, during the age of the dinosaurs, centrifugal force was slightly stronger than it is now. Even so, this centrifugal force remained small compared to gravitational force and would have had little effect on reducing the weight of the dinosaurs.

The buoyancy force provides a more promising explanation.

Today, the largest animals on Earth are whales. They grow large because water provides an upward buoyant force that counteracts gravity. Early paleontologists recognized how the buoyancy of water reduces the effective weight of animals and suggested that the largest dinosaurs – the sauropods - spent much of their time wading in lakes or rivers. However, this idea was later abandoned when fossil trackways and bone structure showed these animals to be truly terrestrial.

After discarding the water hypothesis, paleontologists began promoting the idea that the large size of Mesozoic animals could be explained by claiming that these animals were somehow stronger, lighter, or biologically superior to modern terrestrial animals. Paleontologists assert that dinosaurs’ bones, muscles, and hearts were far stronger and more efficient than those of modern animals. Similarly, to explain the existence of large flying pterosaurs, paleontologists claimed that these creatures were incredibly light and faced no difficulties in flying - despite aerodynamic calculations and experiments with radio-controlled models indicating otherwise.

Physicists, biologists, engineers, and other scientists outside paleontology are dismayed by these dubious claims. These claims show a lack of understanding and respect for the laws of nature. The suggestion that nature once possessed biological tricks that allowed extreme size and then inexplicably forgot them as we approached modern times, conflicts with the Theory of Evolution and it is an affront to rational scientific reasoning.

Public skepticism of these “super-dinosaur” proposals is why many non-scientists have taken matters into their own hands by offering their own flawed attempts to solve the paradoxes of the Mesozoic era. While paleontologists typically ignore these alternative hypotheses, they were clearly infuriated when biologist Brian J. Ford revived the water buoyancy hypothesis - an action that gave voice to the public’s skepticism.

Nevertheless, neither the alternative hypotheses, which violate the laws of nature, nor Ford’s revived buoyancy hypothesis brings us any closer to resolving the paradoxes. The proposal that dinosaurs spent their days soaking in water suffers from the same flaws as before: when dinosaurs left the water, their bodies should have been sluggish like crocodiles, yet fossil trackways show otherwise. On the other hand, if dinosaurs had lived permanently in water, evolutionary pressure would have caused them to lose their legs, just as occurred in the evolution of whales.

For buoyancy to reduce dinosaur weight without eliminating locomotion, dinosaurs would have needed to be immersed in a fluid less dense than their bodies.

Air is a fluid with a much lower density than the bodies of most animals. Near Earth’s surface, air is roughly a thousand times less dense than water, and water is about the same density as the bodies of most vertebrates. Because of air’s comparatively low density, unless a device contains a large volume of air - such as in the case of a hot-air or gas balloon - we typically do not think of air as being capable of providing significant buoyancy. If we assume, as paleontologists do, that the Mesozoic atmosphere was similar to the present atmosphere, then the small buoyant effect of air would have almost no influence on the weight of dinosaurs. However, that assumption is wrong.

If we assume, as paleontologists do, that the Mesozoic atmosphere was similar to the present atmosphere, then the small buoyant effect of air would have almost no influence on the weight of dinosaurs. However, that assumption is wrong.

This is not the first time - nor will it be the last time - people have embraced false assumptions based on biased perception instead of recognizing the truth through evidence, reasoning, and imagination. People once believed the world was flat because they could not imagine standing on an enormous sphere. Before radiometric dating revealed Earth’s true age of 4.6 billion years, many could not imagine it being more than a few thousand years old. Before the theory of evolution, most could not imagine that humans evolved from other species. Millions of years ago, Earth’s atmosphere was substantially thicker than it is today; despite this being a scientifically sound idea, it is one that most people have never considered or even attempted to imagine.

We need to revise our thinking to realize that there is no normal thickness for a planet’s atmosphere. The atmosphere of Mercury - the smallest planet and the planet closest to the Sun - is so thin that, for all practical purposes, it does not have an atmosphere. At the other extreme, the four planets farthest from the Sun - Jupiter, Saturn, Uranus, and Neptune - have such thick atmospheres that they are essentially composed almost entirely of light gases. Even the planets between these extremes show significant variation in atmospheric thickness: Venus’s atmosphere is over ninety times thicker than Earth’s, while Mars’s atmosphere is about 150 times thinner. While we observe this incredible variation in the thickness of these planets’ atmospheres today, we should also recognize that the thickness of these atmospheres has probably changed considerably over the past 4.6 billion years.

Planetary, geological, and atmospheric scientists have speculated about how Earth’s atmosphere must have changed over time. They know its composition must have varied and that volcanic outgassing is the primary source of Earth’s atmosphere, as it is for Venus and Mars. They also know that both Venus and Mars have atmospheres that are about 96 percent carbon dioxide. It is logical to believe that the reason Venus’s atmosphere is so much thicker than that of Mars is because Venus is larger and possibly more geologically active. Earth is even larger than Venus and certainly more geologically active, thus encouraging the belief that Earth’s atmosphere should be much thicker than Venus’s. Yet instead of Earth’s atmosphere being thicker, its current atmosphere is about ninety times thinner than that of Venus.

The reason Earth’s present atmosphere is thinner rather than thicker than Venus’s is that life evolved on Earth. Life can be extremely proficient at removing carbon dioxide from the atmosphere - so proficient that, over millions of years, it can dramatically change atmospheric thickness. Today, Earth is literally covered with carbonate rocks - chiefly limestone and dolomite - that make up about twenty percent of all Earth’s sedimentary rock deposits. These thick and abundant layers of carbon-dioxide-based rocks stand as physical proof that Earth once had an extremely thick, carbon-dioxide-rich atmosphere.

For these planetary, geological, and atmospheric scientists all the evidence was there. Every piece of the puzzle lay in plain sight: all of it pointing to the conclusion that previously the Earth had a much thicker atmosphere. What was missing was reasoning and imagination. That, and the problem that this evidence conflicted with the current scientific dogma that excessive carbon dioxide in the atmosphere will cause runaway global warming.

There is universal agreement among scientists that there was much more carbon dioxide in Earth’s atmosphere during the Mesozoic era. However, this position is problematic for climate scientists who make their living by alarming the public with their global-warming narrative. The claims of global-warming scientists conflict with the evidence: how could a rise of only a few parts per million of carbon dioxide lead to a runaway greenhouse effect if Earth’s earlier atmosphere contained roughly a million times more carbon dioxide than it does today?

Similar to how paleontologists suppressed the teaching of Galileo’s Square-Cube Law because it conflicted with their dogma, the global warming dogma has led to the suppression of evidence showing that atmospheric carbon dioxide levels were once far higher than today's carbon dioxide levels. Despite geological evidence indicating Earth once had a thick carbon dioxide atmosphere - many times thicker than today’s - geologists and atmospheric scientists have struggled to imagine how such an atmosphere could have existed. Constrained by limited imagination and peer pressure, these scientists speculate that Mesozoic era carbon dioxide levels were only ten to a thousand times greater than current levels.

But that is not what the evidence shows. Only with a much thicker atmosphere - one that aligns with the geological and planetary evidence - are we able to solve the numerous paradoxes associated with the Mesozoic era.

In the same way that the buoyancy effect of water allows whales to grow so large, it was the buoyancy effect of an extremely thick atmosphere that allowed dinosaurs to grow more than three times larger than modern terrestrial animals.

Besides explaining the exceptional size of dinosaurs, an extremely thick atmosphere also explains their body form. Paleontologists have been puzzled by the powerful hind legs and muscular tails of these animals, yet these features are ideal for creatures propelling themselves through a dense fluid.

Likewise, we can now explain how dinosaurs were able to grow so tall. In an extremely thick atmosphere, the effective weight of blood in the neck would be much lower, making circulation no more difficult than it is for modern giraffes. Thus, there is no longer any need for speculative ideas about multi-ton hearts, multiple hearts in the neck, or the suggestion that long-necked dinosaurs could never lift their heads.

The thick atmosphere also explains how exceptionally large animals were able to fly. While reptiles cannot fly in today’s thin atmosphere, flight becomes easy in a dense atmosphere for any animal with wing-like structures. Thus, during the Mesozoic era, reptiles not only flew but became the largest fliers in history. Also, just as the thick atmosphere made it possible for reptiles to fly, it also made it possible for much larger birds to fly, and the wings on these birds would not even have to be very large.

A dense atmosphere further explains the uniform global climate of the Mesozoic era. This is precisely what we would expect from a thick atmospheric envelope.

While these are the strongest arguments, there are actually countless more evidence-base arguments supporting the position that previously the Earth had a much thicker atmosphere. Whether one accepts the thick-atmosphere hypothesis or attempts to disprove it, investigation consistently reveals evidence in its favor. The more closely the issue is examined, the more difficult it becomes to deny that the Mesozoic atmosphere was hundreds of times denser than today’s. The success of this framework indicates that the Thick Atmosphere Theory is more than a hypothesis - it is a unifying scientific theory.

The Thick Atmosphere Theory is more than a hypothesis - it is a unifying scientific theory.

The Thick Atmosphere Theory, along with the supporting scientific concepts and theories such as Galileo’s Square-Cube Law, the Science of Flight Equations, and the Theory of Planetary Evolution, are all supported by overwhelming evidence, mathematics, and sound reasoning. With DinosaurTheory and the Thick Atmosphere Theory, science once again makes sense.

Click the link below to read on. DinosaurTheory provides a more thorough explanation of the many important scientific concepts introduced in this brief introductory summary. Understanding these concepts can significantly deepen your knowledge of science and the natural world.

David Esker
M.S. Physics
College Physics Instructor
Resolution of the Large Dinosaur Paradox
Science of Flight Equations
Theory of Planetary Evolution
Author of DinosaurTheory

Science is an ongoing process of discovery. We do not know why our reality exists, we struggle in defining what is life, we do not know how the laws of physics came to be, or who set the values of the physical constants, but we are certain of one thing: our reality is rational.

Click Here To Return to Introduction

Comments, Questions, and Answers

Selected comments and questions are given with the permission of the parties involved.