How was the moon formed?

Question

Does anyone know how earth's moon was formed. I will also accept theroys.

Answer 1

no one knows but here are some theories that can explain the formation of the moon supported by some facts and experiments

Five serious theories have been proposed for the formation of the Moon (not counting the one involving green cheese):

The Fission Theory: The Moon was once part of the Earth and somehow separated from the Earth early in the history of the Solar System. The present Pacific Ocean basin is the most popular site for the part of the Earth from which the Moon came.

The Capture Theory: The Moon was formed somewhere else, and was later captured by the gravitational field of the Earth.

The Condensation Theory: The Moon and the Earth condensed together from the original nebula that formed the Solar System.

The Colliding Planetesimals Theory: The interaction of earth-orbiting and Sun-orbiting planetesimals (very large chunks of rocks like asteroids) early in the history of the Solar System led to their breakup. The Moon condensed from this debris.

The Ejected Ring Theory: A planetesimal the size of Mars struck the earth, ejecting large volumes of matter. A disk of orbiting material was formed, and this matter eventually condensed to form the Moon in orbit around the Earth.

Answer 2

I was forming this theory of mine if the theory of Big Bang is true that is... Well, if all the theories are true...

Volcanic Eruption.
Possibilities:
1. The atmosphere was starting as life was. So the atmosphere could have not been able to catch some strong eruption form a certain volcano (most likely, Mt. Vesuvius or Mt. Krakatoa or Mt. Kilauea)
2. The explosion/s were materialized in one place so then, vacuum [?] froze the lava/magma in space, thus forming the moon.

Possible Proofs:
1. If there was no atmosphere before, that would be possible
2. If there was a very violent explosion,
3. If vacuum can freeze matter
4. that's it...

Answer 3

The Moon, as seen in X-ray light.
The Moon during EarthshineThe inclination of the Moon's orbit makes it implausible that the Moon formed along with the Earth or was captured later; its origin is the subject of some scientific debate.

Early speculation proposed that the Moon broke off from the Earth's crust due to centrifugal force, leaving an ocean basin (presumed to be the Pacific) behind as a scar. This concept requires too great an initial spin of the Earth and the presumption of a Pacific origin is not compatible with the geological standard model, the theory of plate tectonics. Others speculated the Moon formed elsewhere and was captured into its orbit. Two of the other theories include the coformation or condensation theory and the impact theory, which speculates that the Moon formed from the debris that resulted from a collision between the early Earth and a planetesimal.

The coformation or condensation hypothesis posits that the Earth and the Moon formed together at about the same time from the primordial accretion disk, the Moon forming from material surrounding the coalescing proto-Earth, similar to the way the planets formed around the Sun. Some suggest that this hypothesis fails to adequately explain the depletion of iron in the Moon.

Recently, the giant impact hypothesis has been considered a more viable scientific hypothesis for the moon's origin than the coformation or condensation hypothesis. The Giant Impact hypothesis holds that the Moon formed from the ejecta resulting from a collision between a very early, semi-molten Earth and a planet-like object the size of Mars, which has been referred to as Theia or Orpheus. The material ejected from this impact would have gathered in orbit around Earth and formed the Moon. This hypothesis is bolstered by two main observations: First, the composition of the Moon resembles that of Earth's crust, whereas it has relatively few heavy elements that would have been present if it formed by itself out of the same material from which Earth formed. Second, through radiometric dating, it has been determined that the Moon's crust formed between 20 and 30 million years after that of Earth, despite its smallness and associated larger loss of internal heat, although it has been suggested that this hypothesis does not adequately address the abundance of volatile elements in the moon.[3]

At that time the Moon was much closer to the Earth and strong tidal forces deformed the once molten sphere into an ellipsoid, with the major axis pointed towards Earth. When the Moon started to cool a solid crust was formed along its surface, but its molten interior remained displaced in the direction of the Earth. Said otherwise: the crust on the near side was much thinner than on the far side. Especially during the late heavy bombardment, around 3.8 to 4 billion years ago, many large meteorites were able to penetrate the thin crust of the near side but only very few could do so on the far side. Where the crust was perforated the hot lavas from the interior oozed out and spread over the surface, only to cool down later into the maria as we know them nowadays (so they were seas after all, only not of water). This explains the paucity of maria on the far side.

The geological epochs of the Moon are defined based on the dating of various significant impact events in the Moon's history. The period of the late heavy bombardment is determined by analysis of craters and Moon rocks. In 2005, a team of scientists from Germany, the United Kingdom, and Switzerland measured the Moon's age at 4527 ± 10 million years, which would imply that it was formed only 30 to 50 million years after the origin of the solar system.[4]

Answer 4

About 4.5 million years ago, an object the size of Mars crashed into Earth, blowing out enough material to form a companion sphere, the Moon. Within weeks, it is thought, the flung material had reassembled itself into a single clump, and within a year it had formed into the spherical rock that companions us yet. Most of the lunar material, it is thought, came from the Earth's crust, not its core, which is why the moon has so little iron while we have a lot. The theory, incidentally, is almost always presented as a recent one, but in fact it was first proposed in the 1940s by Reginald Daly of Harvard. The only recent thing about it is people paying any attention to it.

Answer 5

The moon could have formed possibly by a huge meteor strike on the earth and a huge chunk that broke off from the earth became moon. The evidence of this approach can be seen by the previous volcanic eruptions on the moon. (This is the best theory I can come up with right now)

Answer 6

I believe, if I may may liberally dip from the various roots (speech) to explain the process, that simply a natural conclusion was formed in the universes that separated matter from its, as to say , "anti-matter" More specifically the separation of Gailtaler Almkäse from its antitheses, Apodemus sylvaticus. Thus the moon was formed.

Answer 7

I thought there was originally a theory about a 9th planet that struck earth, and in the aftermath, earth became bigger and what was left became the moon... but i may be wrong!

Answer 8

The Bible answers that question very clearly. The first chapter of Genesis, verse 16 and 17, tell us: "Then God made two great lights: the greater one to rule the day, and the lesser one to rule the night. He made the stars also. God set them in the firmament (sky) of the heavens to give light on the earth."

Answer 9

i think it mite be the same way the earth was formed ...

Answer 10

In the decades since Apollo astronauts collected moon rocks, one theory has emerged over competing explanations of lunar birth the moon formed when a big object whacked Earth.

Scientists believe the solar system formed 4.56 billion years ago from a cloud or nebula of gas and dust surrounding the newborn sun. The nebula condensed into pebbles, rocks and larger "planetesimals," which collided and fused to create the planets.

A theory that the moon and Earth both condensed or accreted from the same material was rendered doubtful by a major difference in the moons composition the lack of a significant iron core like Earths.

Another theory said the moon formed elsewhere and was somehow captured by Earths gravity. But that seemed physically improbable and did not account for similarities in compositions of the moon and Earth.

The moons composition was enough like Earths mantle and crust to make some believe the moon formed from material hurled off of a rapidly spinning Earth. But hard evidence could not be found.

And none of the old theories explained how the moons oldest rocks solidified from molten rock about 4.44 billion years ago, roughly 100 million years after the solar system formed.

The giant impact theory proposed that at least 50 million years after the solar system formed, a large protoplanet whacked a perhaps still-molten Earth, heating and ejecting debris from both objects. Part of the debris then clumped together to form the moon, which was covered by molten rock from the heat of the collision.

Supercomputer simulations of the early solar system indicated in 1985 that the moon was not formed from huge solid chunks that were ripped off Earth. Instead, a planet-sized object hit a still-molten Earth, hurling into orbit a thick ring of vapor, dust and rocks, part of which clumped together to form the moon.

Data from the Clementine spacecraft, analyzed in 1995, showed the moon contained less iron than previously thought, and thus had a different bulk composition than Earth. That meant Earth and moon could not have accreted from the same nebula in the early solar system. Researchers argued the moon congealed from debris hurled into space by a giant impact.

In July 1997, University of Colorado, Boulder scientists said their computer simulations showed the object striking early Earth must have been three times more massive than Mars. Harvard University work in the 1980s had concluded the object was as massive as Mars.

More Colorado computer simulations, released in September 1997, mimicked conditions in a disk of debris blasted off early Earth by a giant impact. The simulations reveal the moon must have formed within a year after the collision, and at a distance of only 14,000 miles (22,500 kilometers) from Earth, a fraction of its present mean distance of 239,000 miles (384,600 kilometers).

University of Michigan chemists said in November 1997 that the decay of hafnium 182 to tungsten 182 in lunar samples indicated the moon-forming collision happened at least 50 million years after the solar system was born findings confirmed by a new study of other isotopes.

NASA reported in 1999 that gravity and magnetic-field measurements by the Lunar Prospector orbiter show the moons core is roughly 420 miles (680 kilometers) wide, or less than 4 percent of the moons mass. Earths iron core contains about 30 percent of the planets mass. NASA said the fact the cores are so different indicates the moon was made of material blasted off of Earths outer shell by a huge impact.

The early moons orbit was inclined about 10 degrees from Earths equator. Scientists at the Southwest Research Institute in Boulder, Colorado ran computer simulations to show how an object hitting Earth would throw debris into orbit, and some debris would start accreting to form the moon.

Gravitational interactions between the newborn moon and the remaining debris would have tilted the moons orbit, they found. The young moons inclined orbit had been a stumbling block for the impact theory because scientists thought an impact would produce the moon in equatorial orbit.

Two new studies bolster the popular theory that the moon formed from debris after a rogue planet smacked into Earth about 4.5 billion years ago.

One fresh line of evidence for the so-called "big whack" comes from the oldest record of Earth'socean tides ever found 3.2-billion-year-old rocks from South Africa. Pinstriped sand-and-silt layers in the rocks were deposited by daily, fortnightly and monthly tidal cycles.

The layers reveal the primeval moons orbit was nearly circular, as it is today, consistent with the "giant impact theory," said Virginia Tech geologist Ken Eriksson, who led the study in Septembers issue of the journal Geology.

Earth's Offspring? The Collision Theory
One theory has emerged over competing explanations of lunar birth: themoon formed when a big object whacked Earth.Click to learn more.

If the moon formed elsewhere, then was captured intact by Earths gravity, the moons orbit would have been extremely elliptical, and tidal rock layers would not have shown such normal cycles, he said.

Eriksson said the South African rocks also indicate that 3.2 billion years ago, the moon orbited Earth in perhaps a 20-day month and was 25-percent closer to Earth than it is today. But Earth would have spun faster, so there would have been about 550 days in a year.

The second study

In the second study, German geochemists determined Earth and moon each separated into a core, mantle and crust, 50 million to 100 million years after the solar system formed some 4.56 billion years ago.

The study, published in the September 1 issue of the journal Science, adds evidence the moon-forming impact also happened 50 million to 100 million years after the solar system's birth. Only after the impact did oceans of molten rock cool so Earth and moon could fully develop internal layers.

Carsten Munker of the University of Munster said Earths core probably started forming soon after the solar systems 50 millionth birthday. Then a planet-sized object hit Earth, which still might have been covered by an ocean of magma, or molten rock.

Impact debris was hurled into orbit around Earth, and a portion of the fragments consolidated to form the moon, which was so hot a magma ocean covered it. Then, Earth and moon cooled, with the moon developing a core, overlying mantle and uppermost crust, while Earth also completed its core, mantle and crust, Munker said.

A compelling theory

"The impact theory is becoming immensely popular," said University of Utah geologist Marjorie Chan. "Impacts capture peoples imaginations. People like those theories because they are glitzy, 'gee-whiz,' 'wow.' A spectacular collision is more exciting than the Earth just rotating around and capturing a moon somehow."

In the early 1990s, Chan and a student found what were then the worlds oldest confirmed "tidal rhythmites" 900 million-year-old rocks from Big Cottonwood Canyon near Salt Lake City, Utah.

But in their new study, Eriksson and Edward Simpson, a geologist at Pennsylvanias Kutztown University, identified 3.2 billion-year-old, tide-deposited rock layers near Barberton, in eastern South Africa.

Eriksson first found the layers of sand and silty shale which were mildly metamorphosed into quartzite and slate in the 1970s. He suspected they were tidal rocks. He said the new study proved it by showing how the pinstripe sediment patterns coincided with daily, twice-monthly and monthly tidal cycles.

Just as today, rising flood tides deposited light-colored, sandy layers on shallow coastal sea floors and estuaries. When waters went slack, fine silt and clay particles formed thinner dark, muddy layers.

Two sand layers and two silt layers represent a single days two high tides and two low tides. The thicker sand layer up to an inch (25 millimeters) thick was laid down by the days highest high tide, which had a faster current to carry more sand.

Tide patterns

The rocks also display twice-monthly and monthly tide patterns from spring and neap tides.

Spring tides happen twice monthly when Earth, moon and sun are aligned, triggering the months highest high tides with faster currents that deposited thicker sand layers.

Neap tides happen twice monthly when the moon is completely unaligned, producing the months lowest high tides with slow currents that deposited the thinnest sand layers in the 3.2 billion-year-old rocks.

"There were tides today and tides back then, which indicates the moon was in orbit around the Earth at the time," Eriksson said from Australian National University in Canberra, where he is on a fellowship. "Our work indicates a near-circular orbit, which favors the impact model for the formation of the moon."

If the moon formed elsewhere and was captured intact, its speed before capture would have made its orbit around Earth highly elliptical and asymmetrical, Eriksson said.

If that had happened, the rocks would have some sand layers from the few days each month when the moon was close enough to cause tides, then a thick layer of mud representing the lack of tides when the moon was far from Earth.

In the other study, Munker and colleagues studied ancient Earth rocks and meteorites that originated on the moon. They looked for unusual amounts of zirconium 92 produced by the radioactive decay of niobium 92.

Such decay virtually stopped about 50 million years after the solar systems birth because almost all of the niobium 92 was used up by then, Munker said. The study found that unlike asteroids, ancient Earth and moon rocks lacked unusual zicronium 92.

That suggests rocks from Earth and the moon did not solidify from magma until all the niobium 92 was gone, namely, at least 50 million years after the solar system was formed. That, along with earlier research on the decay of hafnium 182 to tungsten 182, implies a big collision formed the moon at least 50 million years after the solar systems birth, and only later did Earth and the moon develop all their distinct layers.

The moons oldest rocks cooled and solidified about 4.44 billion years ago, or about 100 million years after the solar system was born. So the moon must have formed sometime between 50 million and 100 million years after the solar system was born, Munker said.

Munker conducted the study with Munster geochemists Stefan Weyer, Klaus Mezger, Mark Rehkamper and Frank Wombacher, along with planetologist Addi Bischoff.

Also try these informative sites:
http://www.psi.edu/projects/moon/moon.html
http://www.windows.ucar.edu/tour/link=/earth/moon/moon_evolution_overview.html
http://www.psrd.hawaii.edu/Dec98/OriginEarthMoon.html
http://nasw.org/users/sperkins/moonhit.html
http://www.swri.edu/3pubs/ttoday/spring99/moon.htm