If we follow the giant impact theory, the early Moon was probably a hot, liquid sphere made of gravity-bounded debris. The second is the scarcity of volatile substances like water in moon rocks, suggesting that the lunar surface was "baked" longer than Earth's was. 1986. Moon - Moon - Formation, Craters, Orbit: With the rise of scientific inquiry in the Renaissance, investigators attempted to fit theories on the origin of the Moon to the available information, and the question of the Moon's formation became a part of the attempt to explain the observed properties of the solar system (see Solar system: Origin of the solar system). One explanation is that Theia and the early Earth must have had an identical composition to start with. The Giant Impactor Theory is currently the leading theory for the origin of Earth's Moon. Different models showed that the moon should look more like Theia than Earth, which led some to doubt the existence of Theia at all (via The Conversation). Compared to Earth, Theia must have had more of the lighter oxygen isotopes, which suggests that it would have formed further away from the Sun than the Earth. The new impact scenario envisioned that at the end of its formation, Earth collided with another planet-sized body. This restricts the orbit of the impactor to lie near that of the Earth. In 2007, researchers from Caltech showed that the likelihood of Theia having an identical isotopic signature as the Earth is very small (less than 1 percent chance). In chemistry, any element's atomic nucleus is made up of particles known as protons and neutrons; isotopes of an element have the same number of protons in the nucleus as the regular version, but different numbers of neutrons. [4] Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each Solar System body. This proposes that the Moon formed during a collision between the Earth and another small planet, about the size of the planet Mars. The origin of the Moon is usually explained by a Mars-sized body striking the Earth, making a debris ring that eventually collected into a single natural satellite, the Moon, but there are a number of variations on this giant-impact hypothesis, as well as alternative explanations, and research continues into how the Moon came to be formed. Is it right? Here's a brief rundown of the most prominent theories scientists have come up with to explain the moon's origin, including a few relatively wild ones with little observational evidence to back them up. After gazing up at the moon for all those years, however, we're still not exactly sure how it came to be. Hartmann, W. K. 1997. [6] Also, the Moon's titanium isotope ratio (50Ti/47Ti) appears so close to the Earth's (within 4 parts per million) that little if any of the colliding body's mass could likely have been part of the Moon. NEXT: Asteroid Rubble, Some scientists have suggested that the moon condensed from the debris produced when planetesimals the building blocks that grew into Earth, Mars and other full-fledged planets slammed into each other shortly after the solar system formed. These ideas attracted relatively little comment in the scientific community during the next few years. Compared with its present-day age of 13.77 billion years, that's the equivalent of a baby picture taken of you when you were a mere 10 hours old. 5 fascinating facts about the Big Bang, the theory that defines the By studying the past events and processes reflected in the mineral, chemical, and isotopic properties of these rocks, lunar scientists have slowly built a picture of a variegated Moon. This article summarizes calculations that simulate what may have been the most violent event that has ever occurred to the Earth, its collision with the next largest body that was present in its region of accumulations in the early Solar System. Heres how it works. Related: Stephen Hawking says he knows what happened before the Big Bang. In an effort to unravel the history of this period, scientists have applied modern analytic techniques to lunar rock samples. Albert Einstein (left) and Georges Lematre in January, 1900. uk M, Stewart ST. It cannot explain the high angular momentum of the Earth-moon system, for example, or why the moon has such a small iron core compared to that of our planet. But the math didnt add up. The centrifugal force would have concentrated heavy elements such as thorium and uranium on the equatorial plane and at the boundary between the Earth's outer core and mantle. This site uses cookies to assist with navigation, analyse your use of our services, collect data for ads personalisation and provide content from third parties. The Earth has a large iron core, but the moon does not. Moon must have formed at 4.5 Ga or later, long ahead of the proposed nebula dissipation. Once the huge mare lava outflows had diminished, apparently the Moons heat source had run down. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. In the 19th century,George Darwinson of evolution pioneer Charles Darwin put forth the fission theory, which attempted to answer why the moon was so similar to the Earth (via Treehugger). In the 1990's, Dr. Robin Canup wrote a Ph.D. dissertation on the moon's origin and the giant impact hypothesis, which produced new modeling of the aggregation of the debris into moonlets, and eventually, into the moon itself. Theia, an early protoplanet the size of Mars, hit Earth in such a way that it ejected a considerable amount of material away from Earth. Michael Wall is a Senior Space Writer withSpace.comand joined the team in 2010. Our current understanding of physics can only take us so far into the past before all of our theories, including our knowledge of the workings of space and time, break down. The dark spots of the Moon are called lunar maria, a Latin word meaning seas.. The Moon is known to be the cause of ocean tides due to the gravitational attraction it exerts on Earth. Co-formation, however, is somewhat consistent with the low-velocity collision that is required of the Giant-Impact Theory. This could alleviate the tension between the Moon's Earth-like isotopic composition and the different signature expected for the impactor. 10 strange things NASA's Artemis 1 Orion spacecraft took to the moon, Best Star Wars fan films: amateur cinema from a galaxy far, far away, Upcoming space games: Starfield, Star Wars Jedi Survivor, Mass Effect 4 & more, Planet Venus: 20 interesting facts about the scorching world, NASA and Metallica team up for epic Artemis 1 moon rocket video, See the wild Las Vegas Sphere transform into Earth, Mars and the moon (photos), Jam packed issues filled with the latest cutting-edge research, technology and theories delivered in an entertaining and visually stunning way, aiming to educate and inspire readers of all ages, Engaging articles, breathtaking images and expert knowledge. Independent-origin theories, however, had their own problems. One theory that technically doesn't explain how the moon was formed but rather how it got to where it was today is the capture theory (via Space). Astrophysical Observatory, Astrophysics - Earth and Planetary Astrophysics. [36][37][38], Immediate origin of the Moon as a post-impact satellite, Pages displaying wikidata descriptions as a fallback. But Einstein, along with the vast majority of astronomers and physicists at the time, believed that the universe was static, so he added some extra terms to the equations to balance everything out. The lack of volatiles in the lunar samples is also explained in part by the energy of the collision. It's still a massive mystery at the heart of astronomy, but it seems every decade, scientists get closer and closer to unlocking the truth. This failed when lunar rocks showed the same isotope composition as the Earth. Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. [4], This is the now discredited hypothesis that an ancient, rapidly spinning Earth expelled a piece of its mass. It did not happen in one particular location in space, but in a particular location in time. [1][irrelevant citation] The Moon's oxygen isotopic ratios seem to be essentially identical to Earth's. The Moon is the Earths only natural satellite and the fifth largest satellite in the Solar System. In order to bridge the gap between previous studies and provide a consistent survey of the Moon-forming impact parameter space, we present a systematic study of simulations of potential Moon-forming impacts. Finally, the moon has an identical relative abundance of oxygen isotopes as the Earth, meaning it was formed at the same distance from the sun as our home planet. One early theory was that the moon is a sister world that formed in orbit around Earth as the Earth formed. After the capture and fission theories were largely discounted, puzzled scientists began to consider what some call the sister hypothesis, which states the moon formed alongside the Earth. How the Moon Formed: 5 Wild Lunar Theories By Mike Wall published 2 April 2014 Introduction Imelda B. Joson and Edwin L. Aguirre The moon has fascinated humanity for millenia, exerting a. A 2012 study on the depletion of zinc isotopes on the Moon found evidence for volatile depletion consistent with the giant-impact origin for Earth and the Moon. The moon and the Earth are nearly identical in composition. The formation of the Moon took place about 4.5 billion years ago, about 30-50 million years after the formation of the Solar System. About 3.9 billion years ago, one of these formed the great Imbrium Basin, or Mare Imbrium, and its mountain ramparts. We can say, with an extreme degree of confidence based on multiple independent lines of evidence, that our entire observable universe every speck of dust, every star and every galaxy was once crammed into a volume no bigger than a peach with a temperature of over 1 trillion degrees. Dissipation of this disk may have resulted in the formation of the Moon. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. This book remains the prime reference on this subject. Consider supporting ScienceX's mission by getting a premium account. The giant impact theory which states that the moon formed from the a collision between the early Earth and a rocky body called Theiahas become the front runner among the explanations. part may be reproduced without the written permission. Provided by The last few billion years of its history have been calm and essentially geologically inactive except for the continuing rain of impacts, which is also declining over time, and the microscopic weathering due to bombardment by solar and cosmic radiation and particles. Canup's early work, presented in July 1997, suggested the debris from an impact might not make a moon, but only a swarm of moonlets. At first the approach was largely founded on a mathematical examination of the dynamics of the Earth-Moon system. Breaking space news, the latest updates on rocket launches, skywatching events and more! [12] Published in 2012, an analysis of titanium isotopes in Apollo lunar samples showed that the Moon has the same composition as Earth,[13] which conflicts with the Moon forming far from Earth's orbit. [3], The standard giant-impact hypothesis suggests that a Mars-sized body, called Theia, impacted the proto-Earth, creating a large debris ring around Earth, which then accreted to form the Moon. This collision produced enough heat to create magma oceans and ejected a lot of debris into orbit around the Earth, which subsequently coalesced into the moon. In fact, we're not entirely sure how it got there. Things like the angular momentum of the Earth's relationship with the moon and, more damningly, the lack of a significant iron core in the moon mean the theory fell short. In the leading theory of lunar formation, known as the giant impact hypothesis, a collision between two planet-size objects resulted in a young Earth surrounded by a circumplanetary debris disk from which the Moon later accreted. and Terms of Use. Future US, Inc. Full 7th Floor, 130 West 42nd Street, Look it up now! Past, Present, and Future Climate, Windows to the Universe Events at Fall NSTA Conferences, 2007, Motivational Quotes For Everyone, Including Teachers and Students, National Earth Science Teachers Association, National Earth Science Teachers Association (NESTA). Scenarios for lunar origin should be able to explain the Moon's physical and dynamical properties, including chemical composition (volatile and stable isotope ratios), and the Moon's initial thermal state. The study shows that there is a small difference between the Earth and the moon in their oxygen isotope compositiontheir profiles aren't identical after all. [21] This model was popular until the 1980s, and some points in its favor are the Moon's size, orbit, and tidal locking. Even satellites that initially pass within the Roche limit can reliably and predictably survive, by being partially stripped and then torqued onto wider, stable orbits. (Image credit: Getty/ Universal History Archive ). Read more : 13 Jul 2023 12:00:01 Perhaps there was more than one Theia and once, more than one moon as several smaller impacts formed "moonlets" that eventually merged into the moon we see today. A new look at something old Simon, Gargano, and their research team found evidence for the collision theory when they were conducting a study to understand the significant differences in chemical composition between Earth and Moon rocks. The giant impact theory emerged as the "fashionable" theory, but everyone agreed that it was relatively untested and that it would be appropriate to reserve judgement on it until a lot of testing has been conducted. Several very plausible theories have been put forth about the origins of the moon, but none has been completely satisfactory to the astronomical community. Hartmann and Davis were familiar with the work done in the Soviet Union in the 1960's, on the aggregation of planets out of countless asteroid-like bodies called planetesimals. The cosmic microwave background is a huge deal. Use, Smithsonian One of these hit earth late in Earth's growth process, blowing out rocky debris. Subsequent calculations have been directed toward determining whether "successful" outcomes are possible with a wider range of initial conditions than were first used. The moon has exactly the same oxygen isotope composition as the Earth, whereas Mars rocks and meteorites from other parts of the solar system have different oxygen isotope compositions. The giant impact model proposed in the 1970s gets more and more scrutinized with every passing year, and astronomers are still proposing new ideas that fit the growing knowledge on Earth and the moon (via Quantum Magazine). 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Page design by Gregg Herres and William K. Hartmann. The hypothesis requires a collision between a proto-Earth about 90% of the diameter of present Earth, and another body the diameter of Mars (half of the terrestrial diameter and a tenth of its mass). With the results from this study the giant impact theory has crossed another hurdle in explaining the formation of our moon, and we have learned a little more about Theia itself on the way. The crust is where mixed debris would have ended up, whereas the deep interior would have more bits of Theia. The energy liberated during the reaccretion of material in orbit around Earth would have been sufficient to melt a large portion of the Moon, leading to the generation of a magma ocean.