How we know that Earth and the Universe are billions of years old and that evolution is real

Some adherents of creationism believe that the Universe, the Earth, and life were created a few thousand years ago and some completely reject the theory of evolution, while others promote the pseudoscientific argument of intelligent design. One branch of creationism is Young Earth Creationism (YEC), which postulates that the Earth and the Universe are only 6,000 years old. It is based on a literal interpretation of the Book of Genesis, the first book of the Bible, according to which God created the Universe in six days.

In an Instagram reel published in September 2024, YEC proponent Major G. Coleman made several claims about the age of the Universe, the age of the Earth, and evolution. In this article we will explain why two of the claims made by Coleman are false: that the Universe and Earth are only a few thousand years old and that species don’t evolve.

Earth and the Universe are billions of years old

Coleman claimed that we can estimate the age of the Universe by observing solar nebulae that are formed after a star explodes in a supernova. He argued that by taking into account the number of observed nebulae and the frequency of supernovas, the age of the Universe can be known. By “solar nebula” Coleman was likely referring to supernova remnants, a kind of nebula formed after the explosion of massive stars with more than eight times the mass of the Sun.

But this method contains several flaws. On the one hand, this calculation doesn’t take into account the time necessary for stars to form and for them to exhaust their hydrogen reserves before they explode in a supernova. The estimated time for this to occur is millions of years. Therefore, the first supernovae didn’t happen until several million years after the Universe came into existence.

On the other hand, supernova remnants are challenging to observe, as they cool down and merge with the surrounding interstellar medium over time. Scientists have identified hundreds of possible supernova remnants in our galaxy, the Milky Way, so their number is likely higher than currently reported.

But even if we use the method proposed by Coleman, it doesn’t support his claim that the Universe is only 6,000 years old. The estimated frequency at which supernovae occur in the Milky Way is one supernova every 50 years, not one every 26 years, as Coleman claimed.

To date, 383 supernova remnants have been detected in the Milky Way. Multiplied by the frequency of supernovas, the result is that the Universe would be 19,150 years old. If the frequency of supernova occurrence given by Coleman is used instead, then the Universe would be 9,958 years old. Either way, neither of these figures support Coleman’s claim.

The appropriate way for scientists to determine the age of the Universe is by studying the rate at which it is expanding. One way to do this is by observing the cosmic microwave background (CMB), which is the leftover radiation from the Big Bang. This radiation cannot be observed by the naked eye, but can be detected as microwaves.

The CMB isn’t uniform and contains hotter and colder patches (see Figure 1 below), which allows for the identification of different points in the CMB. By measuring the distance between two points in the CMB, it is possible to determine the distance of these points to the Earth using geometry. This allows us to estimate how far the CMB radiation has traveled to reach the Earth, and therefore to estimate when the Big Bang happened.

According to observations of the CBM made by the Atacama Cosmology Telescope, the age of the Universe is around 13.77 billion years. This matches previous estimates made with data obtained by the European Space Agency’s Planck Space Telescope, which indicated an approximate age of 13.8 billion years.

As for the ages of the Solar System and the Earth, these are estimated by radioisotope dating. This technique compares the amount of a naturally occurring radioactive substance in a material with the amount of its decay products. This is possible due to the instability of radioactive substances. This means that over time they release energy in the form of radioactivity, transforming into other more stable substances, known as decay products.

One of the most widely used methods for rock dating, which is highly accurate, is based on uranium decay. Uranium is a radioactive element whose decay product is lead. Uranium occurs naturally in several minerals that are formed when molten rock solidifies. These minerals initially contain negligible amounts of lead. But as time passes and the uranium decays, the levels of lead present in the mineral increase relative to the levels that were present when the mineral was first formed. Since the rate of decay from uranium into lead is known, the amount of lead and uranium present in a rock allows us to know how old the mineral is.

To estimate the age of the Solar System, scientists used uranium decay to analyze meteorites that have fallen to Earth. The oldest meteorites come from asteroids that formed in the early stages of the Solar System, while younger meteorites formed later from planets or moons. The oldest meteorite found to date is about 4,568 million years old, which is the estimated age of the Solar System^[1].

Estimating the age of the Earth is a bit more tricky, as phenomena such as weathering or the movement of tectonic plates transform existing rocks and minerals, creating new rocks and minerals. The oldest minerals found so far are zircons from Australia. Zircons were formed by crystallization as the molten rock that covered the early Earth cooled down. According to uranium decay measurements, those zircons are about 4,374 million years old^[2]. Therefore, the Earth must also be at least 4,374 million years old.

Life has existed on Earth for millions of years

To support his claim that the Earth is only 6,000 years old, Coleman pointed out that the oldest living things on the planet are trees which are 4,500 years old. He was likely referring to Pinus longaeva, a species of bristlecone pine that lives in the mountains of California, Nevada, and Utah. These pines are slow-growing and can live for thousands of years.

The age of these trees can be determined by tree-ring dating. As trees grow, they accumulate layers of cells near the bark. The rate of growth varies throughout the seasons, so each annual seasonal cycle results in a visible growth ring in the wood. Counting these rings provides insight into how old the tree is, which can be done without cutting the trees by taking wood samples from the core of the tree. The oldest known living bristlecone pine is 5,065 years old, according to the U.S. National Park Service.

However, there is an important nuance that Coleman’s claim omitted when he presented bristlecone pines as proof of the age of the Earth: remains of these trees older than 4,500 years old have been found. Dating these remains has been possible thanks to a radioisotope dating technique called radiocarbon dating, which consists of analyzing the amount of carbon-14 present in a sample.

Carbon-14 is a radioactive isotope of carbon that is formed by cosmic rays in the upper layers of the atmosphere. It is subsequently absorbed by plants as carbon dioxide during photosynthesis and incorporated into wood. After the plant dies, the amount of carbon-14 present in the wood starts decaying at a known rate over time. So its proportion relative to the other carbon isotopes decreases, which indicates the age of the wood.

By analyzing the remains from bristlecone pines using radiocarbon dating, scientists have been able to arrange them in a continuous chronological record spanning from the present to 8,253 years ago, which corresponds to the age of the oldest sample.^[3]. Therefore, when analyzed using radiocarbon dating, bristlecone pines refute the claim that the Earth is only 6,000 years old.

Moreover, the use of radiocarbon dating on samples from different plant species has allowed scientists to establish a continuous chronological record spanning 13,910 years^[4].

Since Coleman based part of his argument about the age of the Earth on the longest-lived trees, it’s worth mentioning that there are living plants that predate the aforementioned bristlecone pines. These are plants that reproduce asexually, producing new genetically identical individuals as the older ones die off.

An example of this is the single colony of Lomatia tasmanica on the island of Tasmania. Genetic analysis of the plants, and radiocarbon dating of fossils of the same species, shows that the original individual from which the clones are derived could be at least 43,600 years old^[5].

In addition, radiocarbon dating can be used to analyze other samples apart from wood, like coral. Carbon dioxide dissolves in seawater and is incorporated into corals in the form of calcium carbonate. The analysis of coral samples, together with sedimentary deposits and rock formations containing calcium carbonate, has made it possible to extend the continuous chronological record of carbon-14 samples to 55,000 years^[6].

Moreover, there is evidence that life has existed on Earth for a few billions of years. The oldest evidence of life on Earth is stromatolites, mineral structures created by bacteria capable of photosynthesis, known as cyanobacteria. These bacteria capture carbon dioxide from the atmosphere, which is deposited as carbonates, forming these mineral structures.

The oldest stromatolites found to date come from Greenland and are 3.7 billion years old, indicating that life already existed on Earth at that time^[7]. The unique structure of these minerals—their distinctive thickness, shape, and asymmetry—rules out the possibility that they could have an abiogenic origin^[7]. There are certain marine environments where stromatolites are still forming today, like Hamelin Pool in Australia or Little Darby Island in the Bahamas.

Further evidence of life on Earth exists in the form of fossils. Fossils are the remains of ancient life forms that have been preserved due to the replacement of organic matter by minerals (see Figure 2 below). The fossil record is incomplete, since usually only organisms with hard tissues (wood, bone, shell, or exoskeleton) are preserved. An exception to this is the preservation of organisms within amber (fossilized tree resin).

Fossils can be dated using different methods. One is stratigraphy, which establishes the age of a fossil based on the layer of sedimentary or igneous rocks in which the fossil is found.

Another method is potassium-argon dating. This method is based on detecting argon, a gas produced by the decay of the radioactive element potassium-40, which is naturally present in rocks and living organisms. Potassium-argon dating is useful for dating fossils and rocks from thousands to billions of years ago.

The oldest fossils correspond to organisms that lived in the sea, such as trilobites, which are segmented-bodied animals whose fossils can be traced back to 521 million years ago. The ancestors of today’s vertebrates appeared in the fossil record about 508 million years ago, the earliest fish about 480 million years ago, and the earliest mammal about 225 million years ago. Fossilized spores indicate that land plants began existing about 460 million years ago.

As mentioned above, the fossil record is incomplete, but the fossils that we have found demonstrate that life existed on Earth millions of years ago, which refutes the claim that the Earth is only 6,000 years old.

By logic, this also refutes the claim that the Universe is only 6,000 years old. Notably, fossils of extinct life forms such as trilobites refute another of Coleman’s claim that “life that we see today are the basic kinds of animals and plant life that were originally created”.

The evolution of species is evidenced by the fossil record and genetic similarity between related species

Another premise of YEC, which Coleman explained in the video, is that species don’t evolve. Coleman argued that minor genetic variance in species doesn’t cause evolution  and stated that “time and change make evolution absolutely impossible”.

Evolution is the process by which different types of living organisms develop from pre-existing ones, giving rise to new species. It occurs when certain characteristics become more or less common in a population over successive generations due to natural selection and genetic drift. This allows populations to adapt to a changing environment. On the other hand, failure to adapt to said changes can result in the extinction of a population or species.

There are several independent pieces of evidence that demonstrate the evolution of species.

First, individuals from different species possess structures that point to the existence of a common ancestor. For example, the skeletons of different species contain similar bone structures, which have evolved to fulfill different functions (see Figure 3 below). The wings of birds contain the same bones that are present in human hands, and the same bones are also observed in the fins of whales. The shape is different because the structure has adapted to perform different functions, but it shows that these mammals have a common ancestor.

Another piece of evidence that common ancestors exist is vestigial features. These are structures that have lost all or part of the function they served in an ancestor species. An example of a vestigial organ in humans is the coccyx, or tailbone, the last bone of the spinal column. This bone forms the base of the tail in some ape species, while in humans it anchors some muscles and ligaments.

Examples of vestigial organs in other species include snakes with tiny hind leg bones, whose ancestors had functional legs, and blind fish that live in dark caves and possess vestigial eyes, whose ancestors had functional eyes. The wings of flightless birds such as penguins and ostriches are also a vestigial feature, as these birds can’t fly, although their wings have adapted to perform other functions.

A second piece of evidence for evolution is the existence of now-extinct transitional species in the fossil record. These species display both traits related to their ancestral species and traits related to a descendant species. For example, there are fossils of transitional whale species that have traits from ancestral land-dwelling species and other traits that are present in present-day whales, which were absent from the ancestral land-dwelling species.

One well-documented case is the evolution of whales and dolphins. Their ancestor species was Pakicetus, which lived about 50 million years ago. It was a land mammal the size of a wolf that had a particular bone structure in its ears, inferred to be an adaptation to hear underwater sounds. All present-day whale species have the same ear bone structure. A descendant species of Pakicetus is Ambulocetus, which had the same ear bone structure as well as legs better adapted to swimming.

A descendant species of Ambulocetus, Dorudon, had elongated bodies and vestigial hind limbs, which were no longer useful for walking. These species also had nostrils located at the top of the snout, similar to the blowhole of whales. As for present-day whales and dolphins, they have vestigial hip bones that don’t fulfill the walking function they had in the ancestral species but could play a role in reproduction.

Another striking transitional fossil is Tiktaalik, a fish species that existed 375 million years ago. It was a lobe-finned fish that had several morphological characteristics common to four-legged animals, and is believed to be the common ancestor of all terrestrial vertebrate species (amphibians, reptiles, birds, and mammals). This species had some cranial features that arose as adaptations for living in shallow water, such as a flattened skull, which are also present in early land-dwelling animals.

A third piece of evidence of evolution is the genetic similarity between species with a common ancestor. Genetic analysis makes it possible to study the evolution of genes and how they and their mutations are transmitted across successive generations.

An example of this is the ability to synthesize vitamin C in mammals. Vitamin C is necessary for several vital functions, including wound healing and collagen formation. While most mammalian species are able to synthesize vitamin C in their bodies, humans can’t, so we must incorporate it into our diets or we will get sick.

Recent genetic analysis determined that a mutation in a gene related to the enzyme L-gulono-γ-lactone oxidase is responsible for the inability of humans to synthesize vitamin C^[8]. Humans still possess the gene, but it has undergone a series of mutations that render it non-functional.

Furthermore, all simian species are unable to synthesize vitamin C, which means that the mutation in that gene appeared in a common ancestor of humans, gorillas, chimpanzees, and other monkeys. However, lemurs are able to synthesize vitamin C, so we know that the mutation didn’t affect the common ancestor of lemurs and simians.

In light of the above, there are multiple independent pieces of evidence that demonstrate evolution. Genetic analyses of related species and the presence of vestigial traits in present-day species, as well as the occurrence of transitional species in the fossil record, are clear evidence of evolution.

Evolution can be observed in microorganisms that adapt to their environment

Finally, although evolution is a slow process and the appearance of new species can take millions of years to occur, it is possible to observe the evolution of rapidly-dividing microorganisms in real time. An example of this is the long-term evolution experiment carried out with the bacterium Escherichia coli.

The experiment consists of the successive propagation of bacteria from 12 identical starting populations. This experiment began in 1988 and by 2020 had reached 75,000 generations. During this time, mutations have appeared in the populations, some of which are an advantage for the bacteria in the environment in which they develop.

An example of this is the ability of one of these populations to metabolize citrate in the presence of oxygen. This ability was absent in the original populations and is unusual in wild-type E. coli^[9]. But during the experiment, scientists observed that E. coli growing in citrate-containing growth medium gained this ability through certain mutations. This allowed the bacterium to thrive more rapidly, as the growth medium contained minimal nutrients other than citrate.

It is also possible to observe the evolution of microorganisms in the acquisition of antimicrobial resistance. An experiment with this purpose studied how the yeast Candida albicans adapted to the presence of the antifungal drug fluconazole^[10]. The experiment was performed on several genetically identical populations, some of which were exposed to fluconazole.

Those populations of C. albicans exposed to fluconazole developed genetic alterations that conferred resistance to this substance, which is beneficial in the environment they inhabit. Meanwhile, populations not exposed to fluconazole didn’t develop these alterations or the associated resistance, as they involve a fitness cost and no benefit to the organism when the drug isn’t present.

This shows that selective pressure favors fluconazole-resistant C. albicans only when resistance is advantageous, and works against them when it isn’t, due to the associated fitness cost (see Figure 4).

Another experiment to study evolution was carried out with the yeast Saccharomyces cerevisiae, also known as baker’s yeast^[11]. The experiment was performed on several genetically identical populations in which a gene involved in cell division had been deleted.

The experiment found that populations developed different adaptations to compensate for the functions of the lost gene. This is an example of divergent evolution, that is, the accumulation of differences between initially similar populations.

All in all, the results of these experiments demonstrate the principles of evolutionary theory, as they show how advantageous mutations that occur spontaneously become prevalent in successive generations through natural selection.

Conclusion

Carson’s claim that the Universe is only 6,000 years old is false and refuted by multiple lines of evidence. The alleged evidence that Carson presented about the age of the Universe and the Earth is based on a biased selection of various scientific discoveries (cherry-picking), while omitting those other discoveries that disprove his claims.

According to a wide array of scientific evidence, the Universe is about 13.8 billion years old, and the Earth is at least 4.4 billion years old. There is evidence that life appeared on Earth at least 3.7 billion years ago, and that the different species that exist today are the result of the evolution of early life forms. Finally, the hypotheses of evolutionary theory have been corroborated by experiments with microorganisms.

REFERENCES

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