Origin of the Universe and Evolution of Our Earth and Moon

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What was before the Big Bang?

“The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including the abundance of light elements, the cosmic microwave background radiation, the redshift of galaxies, and the large-scale structure of the universe. The uniformity of the universe, known as the horizon and flatness problems, is explained through cosmic inflation: a phase of accelerated expansion during the earliest stages. Detailed measurements of the expansion rate of the universe place the initial singularity at an estimated 13.787±0.02 billion years ago, which is considered the age of the universe. A wide range of empirical evidence strongly favors the Big Bang event, which is now widely accepted.” ref

“Physicists cannot access anything that existed before the start of time and space, but they have theories. The big bang wasn’t a bang in the traditional sense—but it was nonetheless the start of important things: for one, space; another, time. Thirdly, it began the conditions and processes that eventually resulted in us humans, who can sit here and wonder about space and time. The Big Bang was, effectively, the beginning of the universe. According to the logic of human brains, it seems like there must have been something before the big bang, even if “before” is the wrong word because there was no time until after.” ref

“The good news for us is that physicists do have ways of thinking about—and even empirically studying—the origins of the origin of the universe. Counterintuitive and impossible as it may seem, cosmologists are even making progress in determining which wild ideas might peel back the veil on that early era, even though it remains inaccessible to telescopes. For millennia, what happened before and at the beginning of the universe was not a question scientists could even scratch at. Cosmological queries were the dominion of philosophers, says Jenann Ismael—herself a philosopher of physics at Johns Hopkins University. The most fundamental query, of course, is where we come from—a question as popular among philosophers as it is with the rest of us. Other questions, Ismael says, include doozies such as “What are space and time? Does time have a beginning? Does space have boundaries?” ref

“It’s unclear whether science as a discipline—and scientists as people—will ever be able to answer some questions definitively. After all, no one can “see” before the Big Bang, and no one will ever be able to—at least not directly. But the current and future universe, researchers are learning, may contain clues about the distant past. And as scientists push the boundaries of what can be known, they are testing their theories about the before before—the only way to get closer to potential truth. “I’m happy to listen to any framework, but I only start taking it seriously when it produces a clean observational target that a real instrument can go after,” says Brian Keating, a cosmologist at the University of California, San Diego. “If there isn’t a discriminant you can measure, you’re doing metaphysics with equations.” ref

“Here are a few ideas that he and other scientists take seriously about the cosmos’s ultimate origins:

• The No-Boundary Proposal
• A Bouncing, Cyclic Cosmos
• Mirror Universe
• The Test of Time” ref
• Multiverse (meta-universe or parallel universes) ref, ref

The No-Boundary Proposal

“Quantum mechanics is the physics of the extremely small, ruled by statistics and uncertainty. It’s also what may have shaped the early universe. To understand the quantum cosmos, scientists calculate the probability of a given output from a certain input. In cosmology, the “output” is the universe as it looks today. “The question is: What should the input be?” says Jean-Luc Lehners, former head of the Theoretical Cosmology group at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Germany.

Physicists can break up the problem into chunks of outputs and inputs. If they consider the modern universe to be the output, they can try to figure out what input might have produced it. Then they can step backward by taking that input as a new output and determine what conditions earlier in the universe might have produced that state, and so on. They can theoretically (if they have a lot of time on their hands) do that forever, going in steps to reach the before before—and even before that.” ref

“That infinite regression, however, didn’t make sense to physicists Stephen Hawking and James Hartle, who worked on the question together in the 1980s. They decided to eliminate the universe’s ultimate input—its “beginning.” Instead, they formed a model of the universe called the no-boundary proposal. They suggested time and space form a closed, rounded surface: a four-dimensional hemisphere of spacetime. Does that not make sense? Try this: imagine the universe like the globe of Earth. The big bang is the North Pole. There is no “before” it, just as there is no north of north. Before becomes irrelevant as a concept.” ref

“It’s almost like a Zen idea,” Lehners says. And it’s one he’s toying with in calculations to see if he can re-create the universe we see today from a round place with no north of north. “The no-boundary proposal has a decent amount of support, or at least interest, within the physics community,” says Sean Carroll, a professor of natural philosophy at Johns Hopkins University. He notes that some scientists worry about how well-defined the idea is, but he finds it to be a “natural starting point,” given what we know about quantum gravity.” ref

A Bouncing, Cyclic Cosmos

“Paul Steinhardt, a physicist at Princeton University, has another idea about what happened before the universe as we know it began. It stands in opposition to an idea that he helped shape: this concept suggests that, after the big bang, spacetime expanded very quickly for a very short period of time called inflation. The inflation scenario is meant to explain why the universe looks flat and similar in every place our telescopes can look. After helping to establish inflation theory, however, Steinhardt started doubt the idea—in part because it has required constant tweaking to keep it consistent with our measurements of the cosmos. “It’s really hard to think of a historical example where that actually led to what turns out to be the right answer,” Steinhardt says. “Almost always, that’s a sign that the Titanic is sinking.” ref

“Time to get in a lifeboat, he thought. So he came up with a cyclic universe: one that balloons significantly in size, as ours seems to be doing now, then shrinks a little, and then starts expanding all over again. “When people think about contracting universes, they’re usually thinking about things coming to a crunch,” Steinhardt says—the cosmos collapsing back down into an infinitesimally small point. That’s not what Steinhardt is talking about: he thinks the universe perhaps contracts slowly—to a smaller fraction of its size but not to nothing. That shrinking smooths things out in ways inflation fails to explain, he says, while still producing a cosmos that appears flat and the same in all directions.” ref

“Steinhardt adds that what looks like a big bang is actually not: the universe expands, then slowly contracts and then quickly goes back to expanding. The fast transition between contraction and expansion is not a bang but a “big bounce.” Steinhardt hopes to test this idea not just by examining the past but also by taking data from the present and watching the future carefully. “It makes an obvious prediction, which is that the current phase of accelerated expansion can’t continue forever,” Steinhardt says. “It must end.” ref

“This idea, in turn, raises a new question: “Could it already be in the process of ending now?” he asks. Our measurements about how the universe is expanding come from relatively faraway objects that emitted their light a long time ago. Things could have changed, and we might not know yet because the effects would be hard to measure. “We’d have to look at objects very close by in order to detect it,” Steinhardt says. That’s not cosmologists’ forte, and they would have to develop new techniques and instruments to look nearby for such effects.” ref

“Even more intriguingly, Steinhardt says that because “nothing bad happens to space” during the contraction and bounce, information—even objects such as black holes—can pass from before the bounce to after. “There might be things in our observable universe which are from before,” he says. Keep an eye out.” ref

Mirror Universe

“Another big idea about the before before is of interest to Latham Boyle, a researcher at the Higgs Center for Theoretical Physics at the University of Edinburgh, who was formerly Steinhardt’s graduate student. Like the big bounce concept, Boyle’s favored proposal is pretty simple conceptually—and it similarly eschews inflation. “There’s the universe after the big bang and the universe before the big bang,” he says, “and they’re kind of mirror copies of one another.” ref

“Picture this, Boyle says, like the points of two ice cream cones touching each other, with their contact representing the Big Bang. “Time marches away from the big bang in both directions,” he says. On our side, it goes forward; on the mirror side, it goes backward. What happened before the Big Bang is the reflected opposite of what happened after. And that doesn’t just include time: here, there is matter; there, there is antimatter. Here, left is left; there, left is right.” ref

“Boyle has ideas for observations that could support (or nullify) his theory, which is called the CPT-symmetric (charge-parity-time-symmetric) universe. For one, a CPT-symmetric universe wouldn’t have sent gravitational waves shimmering through space from the beginning of the universe, as classical cosmology theories predict. Astronomers have been hunting for such signals. If these waves are eventually detected, that would rule this idea out.” ref

“Boyle’s hypothesis also predicts that dark matter could be explained by a particular kind of neutrino. He hopes cosmological instruments will reveal more information about neutrinos soon. The model’s connection to particle physics, among other aspects, makes this idea intriguing, Carroll says. “What I like here is the economy,” Keating says, “and the fact that it sticks its neck out,” focusing on the kinds of specific, physical predictions experimentalists like him need.” ref

The Test of Time

“Each of these scientists is attached to their own idea. But Lehners, interviewed late last year, isn’t confident any of them will stand the test of time—whatever time is. “I think it’s completely preposterous that, in the year 2025, we should understand the beginning of the universe,” he says. “Why not in the year 2,000,025 or whatever?” And even if researchers think they are getting close, they could be approaching a false summit: that frustrating place that looks, when you’re hiking, like the top of the mountain but is actually a mere bump blocking your view of the true peak—or your view of what you think is the true peak but is, in fact, just another bump. ” ref

“In general, I think that it’s extremely plausible that there was something before the big bang,” Carroll says, “but it’s also very plausible that the big bang was truly the beginning. There’s too much we’re just unsure about, and I am a bit skeptical that the state of the art is good enough to allow us to draw any firm experimental or observational conclusions out of any of these models.” But cosmologists aren’t studying the ultimate origins because they think the mystery will be resolved in their lifetime. Lehner imagines himself as part of an intergenerational project helping humanity trek closer and closer to a truth we may never find.” ref

“Studying such a physically and philosophically inaccessible topic is fundamentally different from other types of science—those quests at least exist in our plane of space and time. It almost seems like the question isn’t actually within the realm of science. But science often involves probing things we cannot access, at least at the start, philosopher of physics Ismael says. Scientists predicted atoms before we could see them, and black holes and dark matter still lie beyond our ability to detect directly—yet investigating them is clearly scientific. “I think the benchmark for what counts as science has moved,” she says. And it will continue to—including, perhaps, backward to the before that may not be a before.” ref

Multiverse (meta-universe or parallel universes)

“The multiverse is the hypothetical set of all universes. Together, these universes are presumed to comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The different universes within the multiverse are called “parallel universes”, “flat universes”, “other universes”, “alternate universes”, “multiple universes”, “plane universes”, “parent and child universes”, “many universes”, or “many worlds”. One common assumption is that the multiverse is a “patchwork quilt of separate universes all bound by the same laws of physics.” ref

“The concept of multiple universes, or a multiverse, has been discussed throughout history. It has evolved and has been debated in various fields, including cosmology, physics, and philosophy. Some physicists have argued that the multiverse is a philosophical notion rather than a scientific hypothesis, as it cannot be empirically falsified. In recent years, there have been proponents and skeptics of multiverse theories within the physics community. Although some scientists have analyzed data in search of evidence for other universes, no statistically significant evidence has been found. Critics argue that the multiverse concept lacks testability and falsifiability, which are essential for scientific inquiry, and that it raises unresolved metaphysical issues.” ref

“Max Tegmark and Brian Greene have proposed different classification schemes for multiverses and universes. Tegmark’s four-level classification consists of Level I: an extension of our universe, Level II: universes with different physical constants, Level III: many-worlds interpretation of quantum mechanics, and Level IV: ultimate ensemble. Brian Greene’s nine types of multiverses include quilted, inflationary, brane, cyclic, landscape, quantum, holographic, simulated, and ultimate. The ideas explore various dimensions of space, physical laws, and mathematical structures to explain the existence and interactions of multiple universes. Some other multiverse concepts include twin-world models, cyclic theories, M-theory, and black-hole cosmology.” ref

“According to some, the idea of infinite worlds was first suggested by the pre-Socratic Greek philosopher Anaximander in the sixth century BCE. However, there is debate as to whether he believed in multiple worlds, and if he did, whether those worlds were co-existent or successive. The first figures to whom historians can definitively attribute the concept of innumerable worlds are the Ancient Greek Atomists, beginning with Leucippus and Democritus in the 5th century BCE, followed by Epicurus (341–270 BCE) and the Roman Epicurean Lucretius (1st century BCE). In the third century BCE, the philosopher Chrysippus suggested that the world eternally expired and regenerated, effectively suggesting the existence of multiple universes across time. The concept of multiple universes became more defined in the Middle Ages. In the Renaissance, Giordano Bruno (1548–1600) expressed the concept of infinite worlds.” ref 

“The American philosopher and psychologist William James used the term “multiverse” in 1895, but in a different context. The concept first appeared in the modern scientific context in the course of the debate between Boltzmann and Zermelo in 1895. In Dublin in 1952, Erwin Schrödinger gave a lecture in which he jocularly warned his audience that what he was about to say might “seem lunatic”. He said that when his equations seemed to describe several different histories, these were “not alternatives, but all really happen simultaneously”. This sort of duality is called “superposition”. In the 1990s, after recent works of fiction about the concept gained popularity, scientific discussions about the multiverse and journal articles about it gained prominence.” ref 

“Around 2010, scientists such as Stephen M. Feeney analyzed Wilkinson Microwave Anisotropy Probe (WMAP) data and claimed to find evidence suggesting that this universe collided with other (parallel) universes in the distant past. However, a more thorough analysis of data from the WMAP and from the Planck satellite, which has a resolution three times higher than WMAP, did not reveal any statistically significant evidence of such a bubble universe collision. In addition, there was no evidence of any gravitational pull of other universes on ours. In 2015, an astrophysicist may have found evidence of alternate or parallel universes by looking back in time to a time immediately after the Big Bang, although it is still a matter of debate among physicists. Dr. Ranga-Ram Chary, after analyzing the cosmic radiation spectrum, found a signal 4,500 times brighter than it should have been, based on the number of protons and electrons scientists believe existed in the very early universe.” ref 

“This signal—an emission line that arose from the formation of atoms during the era of recombination—is more consistent with a universe whose ratio of matter particles to photons is about 65 times greater than our own. There is a 30% chance that this signal is noise, and not really a signal at all; however, it is also possible that it exists because a parallel universe dumped some of its matter particles into our universe. If additional protons and electrons had been added to our universe during recombination, more atoms would have formed, more photons would have been emitted during their formation, and the signature line that arose from all of these emissions would be greatly enhanced. Chary said: Many other regions beyond our observable universe would exist, with each such region governed by a different set of physical parameters than the ones we have measured for our universe. — Ranga-Ram Chary, USA Today Chary also noted: Unusual claims like evidence for alternate universes require a very high burden of proof. — Ranga-Ram Chary, “Universe Today” The signature that Chary has isolated may be a consequence of incoming light from distant galaxies, or even from clouds of dust surrounding our own galaxy.” ref

“The multiverse is a theoretical concept that the universe as perceived by humans is just one of many universes—perhaps an infinite number—that exist in reality. Also known as parallel universes, the meta-universe, or the Many Worlds theory, the idea has long been a staple of science fiction. Scientists, however, believe multiple universes may be a very real possibility and have cited evidence for their existence. Theories on the multiverse range from matching universes arranged like a patchwork quilt to bubble-shaped universes bumping into one another. One exotic idea holds that each choice made by humans in this universe creates an alternate branch of existence where a different choice becomes the reality. In that scenario, alternate earths may exist where the dinosaurs did not become extinct, or Christopher Columbus did not sail to the New World.” ref

According to the Big Bang theory, the most widely accepted explanation about the origin of the cosmos, the universe was created about 13.7 billion years ago in an enormous explosion. At the time, all the matter in the universe was packed together in an incredibly small point called a singularity. In a space of time measured in billionths of seconds, the universe blew apart in an incredibly hot flash and began expanding in all directions. The first subatomic building blocks of matter—protons, neutrons, and electrons—were created in that flash. After about 380,000 years, the white-hot infant universe began to cool enough to form atoms. The first stars and galaxies were formed after about 400 million years. The Sun, Earth, and the rest of our solar system formed about 4.6 billion years ago—about 9 billion years after the Big Bang.” ref

“The earliest human attempts to understand the universe placed Earth at the center of all existence. It was not until the sixteenth century that Polish astronomer Nicolaus Copernicus deduced that Earth revolved around the Sun and not the other way around. Several decades after Copernicus developed his revolutionary idea, Italian philosopher Giordano Bruno proposed that the universe was infinitely large and contained an infinite number of inhabited worlds. Bruno was burned at the stake for such heresy, but by the eighteenth century, science had advanced to such a point that his idea of an immense cosmos containing many worlds was widely accepted. In the early twentieth century, Irish physicist Edmund Fournier d’Albe suggested the idea that the universe may be just one of many, each “nesting” inside one another and progressing from the unimaginably large to the infinitesimally small.” ref

“While d’Albe’s idea is almost certainly incorrect, scientists do not dismiss the concept of multiple universes. In fact, many see evidence that the multiverse may not only be possible, but also that it is highly probable. The shape and form of such a multiverse is the subject of much speculation and for the moment exists only in scientific theory.” ref

“One of the more popular concepts of the multiverse assumes that the universe is unending and continues for infinity. Because the atoms that make up matter can only be arranged in a finite number of ways, in an infinite universe, it is inevitable that matter will eventually begin repeating itself. In this scenario, countless universes must exist with identical Earths containing the same people, structures, societies, governments, etc., as our Earth. Constrained by the finite speed of light—186,000 miles per second—humans only have the capability of seeing to a certain point at the edge of the universe. Anything beyond that boundary would remain invisible and essentially would be another universe. These multiple universes would be laid out in a pattern like a giant patchwork quilt extending for infinity.” ref

“Another theory proposes that the universe did not expand in a uniform manner at the time of the Big Bang. Instead, some parts of the early universe inflated in fits and spurts at a faster rate than other parts. Each of the expanding pockets formed its own “bubble” universe. The universe humans perceive may have stopped expanding, but other bubbles may still be growing and forming completely new universes with different laws of physics. Some scientists suggest these alternate bubble universes exist outside three-dimensional space and can encounter other universes. If this were to happen, it could cause a cataclysmic event that would destroy both universes and initiate another cosmic big bang.” ref

“Evidence for another type of multiverse is seen in the seemingly bizarre behavior of subatomic particles involved in the science of quantum physics. While protons, neutrons, and electrons are the construction materials that make up atoms, each of those particles is itself made up of smaller, more mysterious particles. Through indirect experimentation, scientists have proven that these particles can exist in more than one physical location at the same time. Once the particle is actually observed, however, the phenomenon ends in what is known as wave function collapse. In the 1950s, American physicist Hugh Everett proposed that the reason this happens is that upon observation, the particle “chooses” a particular state in which to exist. The other states branch off and exist in other realities in other universes.” ref

“Existing theories of physics cannot tell us about the moment of the Big Bang. Extrapolation of the expansion of the universe backwards in time using only classical general relativity yields a gravitational singularity with infinite density and temperature at a finite time in the past. However, this classical gravitational theory is expected to be inadequate to describe physics under these conditions.  Thus, the meaning of this singularity in the context of the Big Bang is unclear. The earliest time at which general relativity can be applied is called the Planck time.  Earlier, during the Planck epoch, when the temperature of the universe was close to the Planck scale quantum gravity effects are expected to be dominant. To date, there is no accepted theory of quantum gravity; above the Planck energy scale, undiscovered physics could influence the expansion history of the universe.” ref

Reality expresses itself in Evolution?

When people think about evolution, it is commonly related to the evolution of life on Earth, but there was an evolution of the universe, an evolution of the stars, planets, and moons in the universe, including our Earth and its unique Moon. An evolution of the continents on our Earth, all that and more, shows “Evolution” is deeply connected to everything around us and the reality we exist in.

“The Big Bang is estimated to have occurred 13.787±0.02 billion years ago, which is considered the age of the universe. A wide range of empirical evidence strongly favors the Big Bang event, which is now widely accepted.” ref

“Extrapolating this cosmic expansion backward in time using the known laws of physics, the models describe an extraordinarily hot and dense primordial universe. Physics lacks a widely accepted theory that can model the earliest conditions of the Big Bang. As the universe expanded, it cooled sufficiently to allow the formation of subatomic particles and, later, atoms. These primordial elements—mostly hydrogen, with some helium and lithium—then coalesced under the force of gravity aided by dark matter, forming early stars and galaxies. Measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to a concept called dark energy. There remain aspects of the observed universe that are not yet adequately explained by the Big Bang models. These include the unequal abundances of matter and antimatter known as baryon asymmetry, the detailed nature of dark matter surrounding galaxies, and the origin of dark energy.” ref

“The Big Bang models offer a comprehensive explanation for a broad range of observed phenomena, including the abundances of the light elements, the cosmic microwave background, large-scale structure, and Hubble’s law. The earliest and most direct observational evidence of the validity of the theory are the expansion of the universe according to Hubble’s law (as indicated by the redshifts of galaxies), discovery and measurement of the cosmic microwave background and the relative abundances of light elements produced by Big Bang nucleosynthesis. More recent evidence includes observations of galaxy formation and evolution, and the distribution of large-scale cosmic structures. These are sometimes called the “four pillars” of the Big Bang models.” ref 

“Precise modern models of the Big Bang appeal to various exotic physical phenomena that have not been observed in terrestrial laboratory experiments or incorporated into the Standard Model of particle physics. Of these features, dark matter is currently the subject of the most active laboratory investigations. Remaining issues include the cuspy halo problem and the dwarf galaxy problem of cold dark matter. Dark energy is also an area of intense interest for scientists, but it is not clear whether direct detection of dark energy will be possible. Inflation and baryogenesis remain more speculative features of current Big Bang models. Viable, quantitative explanations for such phenomena are still being sought. These are unsolved problems in physics.” ref

Evolution of our Sun

“The Sun formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center; the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. The Sun is a Population I, or heavy-element-rich, star. Its formation approximately 4.6 billion years ago may have been triggered by shockwaves from one or more nearby supernovae. This is suggested by a high abundance of heavy elements in the Solar System, such as gold and uranium, relative to the abundances of these elements in so-called Population II, heavy-element-poor, stars. The heavy elements could most plausibly have been produced by endothermic nuclear reactions during a supernova, or by transmutation through neutron absorption within a massive second-generation star. The Sun has an absolute magnitude of +4.83, estimated to be brighter than about 85% of the stars in the Milky Way, most of which are red dwarfs. Since the Sun formed, the main fusion process has involved fusing hydrogen into helium. Over the past 4.6 billion years, the amount of helium and its location within the Sun has gradually changed. About 4 to 7 billion years from now, when hydrogen fusion in the Sun’s core diminishes to the point where the Sun is no longer in hydrostatic equilibrium, its core will undergo a marked increase in density and temperature, which will cause its outer layers to expand, eventually transforming the Sun into a red giant. After the red giant phase, models suggest the Sun will shed its outer layers and become a dense type of cooling star (a white dwarf), and no longer produce energy by fusion, but will still glow and give off heat from its previous fusion for perhaps trillions of years. After that, it is theorized to become an extremely dense black dwarf, giving off negligible energy.” ref

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Evolution of our Earth and Moon

“While the universe is about 13.7 billion years old, our solar system started forming about 4.57 billion years ago when a dense cloud of interstellar dust and gas collapsed to produce a spinning solar nebula. Gravity pulled material inward to create the nuclear fusion reactor that is our Sun. Earth coalesced from the cloud swirling around the Sun about 4.54 billion years ago, initiating the first of Earth’s geological eons, the Hadean Eon. The Hadean, named for Hades, the Greek god of the underworld, was a time of dramatic change. The molten Earth’s surface temperature could have initially exceeded 2,000 K (3,140°F, 1,727°C), and its gravity attracted frequent collisions with planetesimals.” ref

“Other rocky planets, like Mars, Venus and Mercury, also started out molten. The collision of Earth with Theia, a Mars-sized planetary body, formed Earth’s moon during the Hadean Eon. During formation, the Moon was so hot that its entire mantle was molten magma. The Hadean Eon ended approximately 4 billion years ago, by which time Earth had water oceans and a surface temperature not much different from today’s. With the constant recycling of Earth’s crust by plate tectonics, which started about 3.2 billion years ago, Hadean rocks are very rare.” ref

“The oldest solid materials known on Earth are 4.404 billion-year-old zircon crystals found in the Jack Hills of Western Australia. During the first part of the Hadean Eon, Earth was covered in a magma ocean, molten rock with suspended solid crystals floating in a gassy, lava-like fluid that extended all the way to the planet’s core. Convection currents brought warmer melt to the surface as cooler material descended into the roiling magma ocean. Metals and heavier elements descended in these currents to form Earth’s solid metallic inner core, primarily made of iron and nickel, and the liquid outer core that sustains Earth’s magnetic field, known as the geodynamo.” ref

“Samples of anorthosites from the Apollo lunar missions show that our Moon (and other rocky planets) followed similar histories. The light-colored part of the moon, as seen from Earth, consists of these rocks, which can only form as crystals fractionate, floating to the top of large volumes of magma. Unlike the Moon, Earth does not have a flotation crust. Earth’s crust forms from partial melting of the mantle. Today, magma oceans are widely accepted to be a critical stage in the evolution of rocky planets.” ref

“As Earth’s mantle cooled, it is thought to have solidified from the middle outward. With the large temperature gradient at its surface, the magma ocean would have cooled by transferring heat from deep in its interior to the atmosphere, eventually crystallizing into a mush. Recent studies have shown that, at the pressures and temperatures of the lower mantle, magma liquids become progressively more iron-rich and may actually be denser than the solids.” ref

“The molten proto-Earth in the “Hadean Eon” is the first and oldest of the four geologic eons of Earth’s history. The oldest detrital zircon crystals in rocks to about 4.4 billion years ago, soon after the formation of Earth’s crust and Earth itself, and oldest rocks found on Earth date to about 4.0 billion years ago. The giant impact hypothesis for the Moon’s formation states that shortly after formation of an initial crust, the proto-Earth was impacted by a smaller protoplanet, which ejected part of the mantle and crust into space and created the Moon.” ref, ref

“Detrital zircon crystals dated to 4.4 billion years ago show evidence of having undergone contact with liquid water, suggesting that Earth already had oceans or seas at that time. However, from crater counts on other celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 billion years ago, and concluded around 3.8 billion years ago, at the end of the Hadean. In addition, volcanism was severe due to the large heat flow and geothermal gradient.” ref

“Radiometric dating of rocks from the Moon’s surface were brought to Earth and date to around 4.53 billion years old, and evidence suggests the Moon formed even later, 4.48 billion years ago. The giant-impact hypothesis, sometimes called the Theia Impact, is an astrogeology hypothesis that suggests the Proto-Earth collided with a Mars-sized co-orbital protoplanet Theia approximately 4.5 billion years ago in the early Hadean eon in an massive impact, and some of the ejected debris from the impact event later re-accreted to form the Moon. Analysis of lunar rocks suggests that the impact might have been a direct hit, causing a fragmentation and thorough mixing of both parent bodies.” ref, ref

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Evolution of Earth Water (Late Heavy Bombardment or lunar cataclysm)?

“You (atheists) still cannot say HOW Life started on a sterile planet sterilized at 6000 degrees for millions of years.”

My response: It was likely a dual process that produced Earth’s water, involving hydrogen from within the Earth, as well as water-rich asteroids and comets, all of which played a role in its formation. The Earth seems to have gained water from water-rich asteroids and comets during the Late Heavy Bombardment (roughly 4.1–3.8 billion years ago), explained by science, as well as how Earth received organic ingredients from asteroids (Asteroids Reveal The 5 Key Genetic Ingredients For Life on Earth), and developed environments that enabled the emergence of early life (basic life existed 3.5–3.7 billion years ago).” ref, ref, ref, ref

“Material gathered from the 4.5-billion-year-old asteroid Bennu, which formed from minerals and water ice in a primordial nebula contained long chains of organic molecules, richer in nitrogen and oxygen. Researchers suggest the organic compounds formed when heat from the radioactive decay of unstable atoms in the rock warmed the asteroid. The frozen chunks of ammonia and carbon dioxide combined chemically to form carbamates, which subsequently polymerized into a gum-like material. The nitrogen-rich composition of carbamate may have played a role in the formation of amino acids, nucleobases, and other chemical precursors that could have contributed to the prebiotic inventory necessary for the emergence of life.” ref

“The earliest evidence of possibly the oldest forms of life in the form of fossilized microorganisms in hydrothermal vent precipitates from the Nuvvuagittuq Belt, that may have lived as early as 4.28 billion years ago, not long after the oceans formed 4.4 billion years ago. Possible “remains of biotic life” were found in 4.1 billion-year-old rocks in Western Australia. The earliest clear evidence of life comes from biogenic carbon signatures and stromatolite fossils discovered in 3.7 billion-year-old metasedimentary rocks from western Greenland. The evolution of photosynthesis by cyanobacteria, around 3.5 billion years ago, eventually led to a buildup of its waste product, oxygen, in the oceans. After free oxygen saturated all available reductant substances on the Earth’s surface, it built up in the atmosphere, leading to the Great Oxygenation Event around 2.4 billion years ago. While microorganisms formed the earliest terrestrial ecosystems at least 2.7 Ga, the evolution of plants from freshwater green algae dates back to about 1 billion years ago.” ref

“Earth in the early Hadean had a very thick hydride-rich atmosphere whose composition likely resembled the solar nebula and the gas giants, with mostly water vapor, methane and ammonia. As the Earth’s surface cooled, vaporized atmospheric water condensed into liquid water and eventually a superocean covering nearly all of the planet was formed, turning Earth into an ocean planet. Volcanic outgassing and asteroid bombardments eventually altered the Hadean atmosphere into the nitrogen– and carbon dioxide-rich, weakly reducing Paleoarchean atmosphere.” ref, ref

“The origin of water on Earth is the subject of a body of research in the fields of planetary science, astronomy, and astrobiology. Earth is unique among known planets in having oceans of liquid water on its surface. Liquid water, which is necessary for all known forms of life, continues to exist on the surface of Earth because the planet is at a far enough distance (known as the habitable zone) from the Sun that it does not lose its water, but not so far that low temperatures cause all water on the planet to freeze. It was long thought that Earth’s water did not originate from the planet’s region of the protoplanetary disk. Instead, it was hypothesized water and other volatiles must have been delivered to Earth from the outer Solar System later in its history. Recent research, however, indicates that hydrogen inside the Earth played a role in the formation of the ocean. The two ideas are not mutually exclusive, as there is also evidence that water was delivered to Earth by impacts from icy planetesimals similar in composition to asteroids in the outer edges of the asteroid belt.” ref

“A range of evidence suggests that there may instead have been a more extended period of lunar bombardment, lasting from approximately 4.2 billion years ago to 3.5 billion years ago. The apparent clustering of ages of these impact melts, between about 3.8 and 4.1 billion years ago, led investigators to postulate that those ages record an intense bombardment of the Moon. The “lunar cataclysm” and proposed that it represented a dramatic increase in the rate of bombardment of the Moon around 3.9 billion years ago. Consistent with the cataclysm hypothesis, none of their ages was found to be older than about 3.9 billion years ago. Nevertheless, the ages do not “cluster” at this date, but span between 2.5 and 3.9 billion years ago. Dating of howardite, eucrite, diogenite, and H chondrite meteorites originating from the asteroid belt reveal numerous ages from 3.4–4.1 billion years ago and an earlier peak at 4.5 billion years ago.” ref

“The significance of the lack of impact melt rocks older than about 4.1 billion years ago is contrast by a hypothesis that does not involve a cataclysm and that old melt rocks did exist, but that their radiometric ages have all been reset by the continuous effects of impact cratering over the past 4 billion years. Furthermore, it is possible that these putative samples could all have been pulverized to such small sizes that it is impossible to obtain age determinations using standard radiometric methods. Scientists continue to study the bombardment history of the moon in an attempt to clarify the history of the inner solar system. According to this alternative hypothesis, the cluster of impact melt ages near 3.9 billion years ago simply reflects material being collected from a single impact event, and not several.” ref

“Before the formulation of the Late Heavy Bombardment or lunar cataclysm hypothesis, geologists generally assumed that Earth remained molten until about 3.8 billion years ago. This date could be found in many of the oldest-known rocks from around the world, and appeared to represent a strong “cutoff point” beyond which older rocks could not be found. These dates remained fairly constant even across various dating methods, including the system considered the most accurate and least affected by environment, uranium–lead dating of zircons. As no older rocks could be found, it was generally assumed that Earth had remained molten until this date, which defined the boundary between the earlier Hadean and later Archean eons. Nonetheless, in 1999, the oldest known rock on Earth was dated to be 4.031 billion years old, and is part of the Acasta Gneiss of the Slave Craton in northwestern Canada.” ref

“Older rocks could be found, however, in the form of asteroid fragments that fall to Earth as meteorites. Like the rocks on Earth, asteroids also show a strong cutoff point, at about 4.6 billion years ago, which is assumed to be the time when the first solids formed in the protoplanetary disk around the then-young Sun. The Hadean, then, was the period of time between the formation of these early rocks in space, and the eventual solidification of Earth’s crust, some 700 million years later. This time would include the accretion of the planets from the disk and the slow cooling of Earth into a solid body as the gravitational potential energy of accretion was released.” ref

“A vast global ocean may have covered early Earth during the early Archean eon, 4 to 3.2 billion years ago, a side effect of having a hotter mantle than today. Challenge earlier assumptions that the size of the Earth’s global ocean has remained constant over time and offer clues to how its size may have changed throughout geologic time, and could help explain how and where single-cell organisms first emerged on Earth. Most of Earth’s surface water exists in the oceans. But there is a second reservoir of water deep in Earth’s interior, in the form of hydrogen and oxygen attached to minerals in the mantle.” ref, ref

Earth’s “Proterozoic eon” 2.5 billion to 538.8 million years ago

“The Proterozoic eon lasted from 2.5 billion to 538.8 million years ago. In this time span, cratons grew into continents with modern sizes. The change to an oxygen-rich atmosphere was a crucial development. Life developed from prokaryotes into eukaryotes and multicellular forms. The Proterozoic saw a couple of severe ice ages called Snowball Earths. After the last Snowball Earth about 600 million years ago, the evolution of life on Earth accelerated. About 580 million years ago, the Ediacaran biota formed the prelude for the Cambrian Explosion.” ref

“The Proterozoic is subdivided into three geologic eras (from oldest to youngest): the Paleoproterozoic, Mesoproterozoic and Neoproterozoic. It covers the time from the appearance of free oxygen in Earth’s atmosphere to just before the proliferation of complex life on the Earth during the Cambrian Explosion. The name Proterozoic combines two words of Greek origin: protero- meaning “former, earlier”, and -zoic, meaning “of life.” ref

“Well-identified events of this eon were the transition to an oxygenated atmosphere during the Paleoproterozoic; the evolution of eukaryotes via symbiogenesis; several global glaciations, which produced the 300 million years-long Huronian glaciation (during the Siderian and Rhyacian periods of the Paleoproterozoic) and the hypothesized Snowball Earth (during the Cryogenian period in the late Neoproterozoic); and the Ediacaran period (635–538.8 million years ago), which was characterized by the evolution of abundant soft-bodied multicellular organisms such as sponges, algae, cnidarians, bilaterians and the sessile Ediacaran biota (some of which had evolved sexual reproduction) and provides the first obvious fossil evidence of life on Earth.” ref

“Snowball Earth” during the Neoproterozoic era, 720 to 635 million years ago

“The Snowball Earth is a geohistorical hypothesis proposing that during one or more of Earth‘s icehouse climates, the planet’s surface was nearly entirely frozen, with little or no liquid water exposed. This global glaciation hypothesis is most commonly associated with the Cryogenian Period, which included two major glacial episodes: the Sturtian (c. 717–660 million years ago) and Marinoan (c. 650–635 million years ago). Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for global glaciation and the geophysical feasibility of an ice– or slush-covered ocean, and they emphasize the difficulty of escaping an all-frozen condition. Several unanswered questions remain, including whether Earth was a full “snowball” or a “slushball” with a thin equatorial band of open (or seasonally open) water. The Snowball Earth episodes are proposed to have occurred before the sudden radiations of multicellular bioforms known as the Avalon and Cambrian explosions; the most recent Snowball episode may have triggered the evolution of multicellularity.” ref

“Snowball Earth” events, occurred at least twice during Earth’s Neoproterozoic era, 720 to 635 million years ago. Climate modelers have known that if the Earth became sufficiently cold, the high reflectivity of its snow and ice could create a “runaway” feedback loop that would create more sea ice and colder temperatures until the planet was covered in ice. researchers used a sophisticated climate model that represents atmospheric and ocean circulation, as well as the formation of sea ice, under different conditions. It is the same type of climate model that is used to predict future climate scenarios.” ref

“Researchers applied their model to the aftermath of a hypothetical asteroid strike in four distinct periods of the past: preindustrial (150 years ago), Last Glacial Maximum (21,000 years ago), Cretaceous (145 to 66 million years ago), and Neoproterozoic (1 billion to 542 million years ago). For two of the warmer climate scenarios (Cretaceous and preindustrial), the researchers found that it was unlikely that an asteroid strike could trigger global glaciation. But for the Last Glacial Maximum and Neoproterozoic scenarios, when the Earth’s temperature may have been already cold enough to be considered an ice age — an asteroid strike could have tipped Earth into a “Snowball” state.” ref

“What surprised researchers most in their results is that, given sufficiently cold initial climate conditions, a ‘Snowball’ state after an asteroid impact can develop over the global ocean in a matter of just one decade. By then the thickness of sea ice at the Equator would reach about 10 meters. This should be compared to a typical sea ice thickness of one to three meters in the modern Arctic. As for the chances of an asteroid-induced “Snowball Earth” period in the years to come, the researchers said it was unlikely — due in part to human-caused warming that has heated the planet — even though other impacts could be as devastating.” ref

Damien Marie AtHope’s Art

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“Here are the supercontinents: Vaalbara (3.6 billion years ago), Ur (3.1 billion years ago), Kenorland (2.72 billion years ago), Arctica (2.565 billion years ago), Atlantica (2 billion years ago), Columbia (Nuna) (1.6 billion years ago), Rodinia (1.26 billion years ago), Pannotia (650 million years ago), Gondwana (600 million years ago),  Laurasia (350 million years ago), Pangaea (335 million years ago), and Pleistocene epoch (Current Continents) 2.58 million years ago.” ref, ref, ref, ref, ref, ref, ref, ref, ref, ref, ref, ref, ref

Evolution of the Supercontinents

“In geology, a supercontinent is the assembly of most or all of Earth‘s continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, “a grouping of formerly dispersed continents”, which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent. Moving under the forces of plate tectonics, supercontinents have assembled and dispersed multiple times in the geologic past.” ref

“Vaalbara is a hypothetical Archean supercontinent consisting of the Kaapvaal craton (in present-day eastern South Africa) and the Pilbara Craton (in present-day north-western Western Australia). E. S. Cheney derived the name from the last four letters of each craton‘s name. The two cratons consist of continental crust dating from 3.6 billion years ago; this timing would make Vaalbara one of Earth‘s earliest supercontinents.” ref

“Ur is a hypothetical supercontinent that formed in the Archean eon around 3.1 billion years ago. In a reconstruction by Rogers, Ur is half a billion years older than Arctica and, in the early period of its existence, probably the only continent on Earth, making it a supercontinent despite probably being smaller than present-day Australia. In more recent works geologists often refer to both Ur and other proposed Archaean continental assemblages as supercratons. Ur can, nevertheless, be half a billion years younger than Vaalbara, but the concepts of these two early cratonic assemblages are compatible, in some forms.” ref

“Kenorland is a hypothetical Neoarchean supercontinent. If it existed, it would have been one of the earliest known supercontinents on Earth. It is thought to have formed during the Neoarchaean Era c. 2.72 billion years ago by the accretion of Neoarchaean cratons and the formation of new continental crust. It comprised what later became Laurentia (the core of today’s North America and Greenland), Baltica (today’s Scandinavia and Baltic), Western Australia and Kalaharia.” ref

“Arctica is a hypothetical ancient continent which formed approximately 2.565 billion years ago in the Neoarchean era. It was made of Archaean cratons, including the Siberian Craton, with its Anabar/Aldan shields in Siberia, and the Slave, Wyoming, Superior, and North Atlantic cratons in North America. Arctica was because the Arctic Ocean formed by the separation of the North American and Siberian cratons.” ref

“Atlantica (Greek: Ατλαντικα; Atlantika) is an ancient continent that formed during the Proterozoic about 2 billion years ago from various 2 billion years old cratons located in what are now West Africa and eastern South America. The name, was chosen because the parts of the ancient continent are now located on opposite sides of the South Atlantic Ocean.” ref

“Columbia, also known as Nuna or Hudsonland, is a hypothetical ancient supercontinent. It is thought to have existed in the Paleoproterozoic era and it  assembly 1.82 billion years ago. The name Columbia was chosen because critical evidence for the supercontinent was provided by the relationship between the Columbia region of North America (centered on the state of Washington) and east India. The naming is not universally accepted and thus another name was proposed the Nuna (from Inuit “lands bordering the northern oceans”) for the Proterozoic core of Laurentia plus Baltica.” ref

“Rodinia, is a hypothetical supercontinent during the Proterozoic Eon (2.5 billion to 541 million years ago and formed about 1.2 billion years ago, at the beginning of the Stenian Period (which lasted from 1.2 billion to 1 billion years ago).” ref

“Pannotia, also known as the Vendian supercontinent, Greater Gondwana, and the Pan-African supercontinent, was a relatively short-lived Neoproterozoic supercontinent that formed at the end of the Precambrian during the Pan-African orogeny (650–500 million years ago), during the Cryogenian period, and broke apart 560 million years ago with the opening of the Iapetus Ocean, in the late Ediacaran and early Cambrian.” ref

“Gondwana, was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today’s continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian subcontinent. The continents of Australia and East Antarctica were still separated from India, eastern Africa, and Kalahari by c. 600 million years ago, when most of western Gondwana had already been amalgamated. By c. 550 million years ago, India had reached its Gondwanan position, which initiated the Kuunga orogeny (also known as the Pinjarra orogeny).” ref

“Laurasia (otherwise known as the ” Old Red Sandstone Continent “) was a terrestrial continent that formed about 650 million years ago, when the supercontinent Rodinia split into several parts: Laurasia constituted the central body. It was composed of four provinces, North America (” Laurentia “), Northern Europe (” Baltica “), Central Europe (” Avalonia “) and Asia (” Angara “). Between the Ordovician and Devonian periods , approximately 500–400 million years ago, Laurentia, Avalonia and Baltica joined together into the ” North Atlantic Continent ” with the formation of the Caledonian Orogeny and the Appalachian Orogeny. Between the Carboniferous and Permian periods , between 350 and 250 million years ago, the North Atlantic continent collided with the Angara continent, forming the Uralo-Altaic Orogeny. Simultaneously, the collision between the north-central continent of Laurasia and the southern-central continent of Gondwana gave rise to the Hercynian Orogeny , resulting in Laurasia disappearing 290 million years ago, giving rise to Pangaea , through collision with Gondwana.” ref

“Pangaea or Pangea, was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 million years ago, and began to break apart about 200 million years ago, at the end of the Triassic and beginning of the Jurassic. Pangaea was C-shaped, with the bulk of its mass stretching between Earth‘s northern and southern polar regions and surrounded by the superocean Panthalassa and the Paleo-Tethys and subsequent Tethys Oceans. Pangaea is the most recent supercontinent to have existed and was the first to be reconstructed by geologists.” ref

“A supercontinent cycle is the break-up of one supercontinent and the development of another, which takes place on a global scale. Supercontinent cycles are not the same as the Wilson cycle, which is the opening and closing of an individual oceanic basin. The Wilson cycle rarely synchronizes with the timing of a supercontinent cycle. However, supercontinent cycles and Wilson cycles were both involved in the creation of Pangaea and Rodinia.” ref

“The Pleistocene (referred to colloquially as the Ice Age), is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth’s most recent period of repeated glaciations. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing a faunal interchange between the two regions and changing ocean circulation patterns, with the onset of glaciation in the Northern Hemisphere occurring around 2.7 million years ago. During the Early Pleistocene (2.58–0.8 Ma), archaic humans of the genus Homo originated in Africa and spread throughout Afro-Eurasia. The end of the Early Pleistocene is marked by the Mid-Pleistocene Transition, with the cyclicity of glacial cycles changing from 41,000-year cycles to asymmetric 100,000-year cycles, making the climate variation more extreme.” ref

“The Late Pleistocene witnessed the spread of modern humans outside Africa as well as the extinction of all other human species. Humans also spread to the Australian continent and the Americas for the first time. The Late Pleistocene, from around 50,000 years ago onwards, was marked by the extinction of most large terrestrial animals outside of Africa, an extinction event otherwise unprecedented in the geological record due to its extreme size bias. Most authors suggest that climate change, the expansion of modern humans, or the combination of both were the likely causes of the extinctions. The modern continents were essentially at their present positions during the Pleistocene, the plates upon which they sit probably having moved no more than 100 km (62 mi) relative to each other since the beginning of the period. In glacial periods, the sea level would drop by up to 120 m (390 ft) lower than today during peak glaciation, exposing large areas of the present continental shelf as dry land.” ref

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Evolution of Life on Earth

“The Earth is about 4.54 billion years old. Highly energetic chemistry is thought to have produced a self-replicating molecule around 4 billion years ago, and half a billion years later the last common ancestor of all life existed. The current scientific consensus is that the complex biochemistry that makes up life came from simpler chemical reactions. The beginning of life may have included self-replicating molecules such as RNA and the assembly of simple cells. The earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. Microbial mat fossils have been found in 3.48 billion-year-old sandstone in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old metasedimentary rocks discovered in Western Greenland as well as “remains of biotic life” found in 4.1 billion-year-old rocks in Western Australia. Commenting on the Australian findings, Stephen Blair Hedges wrote: “If life arose relatively quickly on Earth, then it could be common in the universe.” Scientists reported identifying a set of 355 genes from the last universal common ancestor of all organisms living on Earth.” ref

“All life on Earth—including humanity—shares a last universal common ancestor, which lived approximately 3.5–3.8 billion years ago. The fossil record includes a progression from early biogenic graphite to microbial mat fossils to fossilized multicellular organisms. Existing patterns of biodiversity have been shaped by repeated formations of new species (speciation), changes within species (anagenesis), and loss of species (extinction) throughout the evolutionary history of life on Earth. Morphological and biochemical traits tend to be more similar among species that share a more recent common ancestor, which historically was used to reconstruct phylogenetic trees, although direct comparison of genetic sequences is a more common method today. Evolution (of life on Earth) is the change in the heritable characteristics of biological populations over successive generations. It occurs when evolutionary processes such as genetic drift and natural selection act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation.” ref

“More than 99% of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth’s current species range from 10 million to 14 million, of which about 1.9 million are estimated to have been named and 1.6 million documented in a central database to date, leaving at least 80% not yet described. All organisms on Earth are descended from a common ancestor or ancestral gene pool. Current species are a stage in the process of evolution, with their diversity the product of a long series of speciation and extinction events. The common descent of organisms was first deduced from four simple facts about organisms: First, they have geographic distributions that cannot be explained by local adaptation. Second, the diversity of life is not a set of completely unique organisms, but organisms that share morphological similarities. Third, vestigial traits with no clear purpose resemble functional ancestral traits. Fourth, organisms can be classified using these similarities into a hierarchy of nested groups, similar to a family tree. Evidence for common descent has come from the study of biochemical similarities between organisms. For example, all living cells use the same basic set of nucleotides and amino acids. The development of molecular genetics has revealed the record of evolution left in organisms’ genomes: dating when species diverged through the molecular clock produced by mutations. For example, these DNA sequence comparisons have revealed that humans and chimpanzees share 98% of their genomes, and analyzing the few areas where they differ helps shed light on when the common ancestor of these species existed.” ref