What current theory for the origin of Earth's moon?

Answer 1

One theory is that the earth and moon were originally one planet, but that something (perhaps a collision from another large body) caused it to split into two unequal parts. Neither part, obviously, was originally spherical, but centripetal forces and gravity, over thousands, perhaps millions, of years, shaped them into spheres. A variant on this theory has one or both of the bodies being completely obliterated by the impact, then eventually pulled back together, by gravity, into two separate bodies. == See the linked question below [Is the moon artificial] for some other possibilities for the origin of the moon.

Answer 2

By current theroy I'm guessing you mean the proto planetary collision theroy. The composition of the moon compared with Earth, the age of the rocks and fast formation of the moon through evidence of the rock, the speed at which the moon is moving away from the Earth and the accelleration of it's escape as mapped in geology, just to name a few. Also, due to the large size of of the Earth's moon, it is seemly improbable that such a large body would have been captured by Earth's gravity.

Answer 3

i only know of two and they are the impact theory and the capture theory.

The third theory for the Moon's formation is that it formed in place from accretion, gradually gaining mass just as all the other planets did.

All three theories of the Moon's origin have some major problems.

1. The currently-dominant "giant impact" theory is that another proto-planet perhaps as large as Mars formed in or near the orbit where the proto-Earth also formed; perhaps in one of the semi-stable "trojan" points in the Earth's orbit. Those trojan points are only SEMI-stable; if the two objects are both quite large, one of them is likely to collide into the other. This would explain the Earth's large iron core, which is larger than any of the other planets, as the two proto-planet's cores would have merged. The impact threw enough surface and crust material from both planets into space, which then coalesced to form the Moon.

Problem: we can't come up with a mathematical model that shows the debris forming a moon, rather than re-impacting the Earth or being thrown into interplanetary space.

2. The "Capture" hypothesis proposes that some other body, perhaps formed elsewhere, wandered into the solar system and was gravitationally captured, becoming our Moon.

Problem; The Moon's rocks that the Apollo astronauts brought back in 1970 through 1973 are too much like Earth rocks for them to have come from someplace far away.

Problem: We can't figure out a mathematical model that shows an asteroid or object from elsewhere being captured into its current orbit or anything LIKE its current orbit.

3. Accretion: Once the most plausible model, the accretion model has flaws of its own. We can't figure out how the planetary dust would form into what is almost a co-planet of the Earth, rather than becoming part of the Earth itself.

Clearly, there's a lot we don't know about the Moon! But once our scientists start living there full time, we'll figure it out.

Answer 4

The theory is this: not long after the earth was born, the orbits of the planets were not yet stabilized.. One of these planets, a Mars-sized object now called Theia, collided with Earth, ejecting a huge amount of molten rock into space. This material, a spun around in the area around the earth, was caught in the earth's gravitational field and eventually formed the moon. Some of the material naturally returned to earth. But the bulk of the material formed the moon. Which is why the moon and the earth are so much alike, as far as geology is concerned.

Answer 5

Scientists have found that the moon is made up of the same rock and materials that can be found on Earth, and the extremely close proximity, as well as its rotation. This evidence supports the current theory about our moon's origin as the giant impact theory that states that a protoplanet about the size of Mars blasted the side of Earth during its molten rock stage and a chunk of it flew off and formed our moon.

Answer 6

Shortly after the solar system formed, when everything was still brand new and none of the planets had fully formed yet, there were probably a LOT of massive objects in crazy orbits around the center of mass, the newborn Sun.

The three main theories about the formation of the Moon are:

1. The Earth and the Moon formed together, at the birth of the solar system.

2. The Earth and the Moon formed separately, and somehow the Moon got caught in the Earth's gravity well.

3. Two large planets collided in orbit. The cores of those planets came together to form the Earth, while the blown-into-space mass ejected from the collision came together in orbit around the new Earth and coalesced to form the Moon.

Until the Apollo astronauts went to the Moon and gathered up a few hundred pounds of moon rocks, there was no theory that was clearly accepted. But when NASA analyzed the Moon rocks and found that they were essentially similar to Earth rocks, this gave option #3 a boost. And currently, the math of a massive collision seems to make sense better that co-formation or lunar capture.

Answer 7

There are four scientific theories for the formation of the Moon.

Fission Hypothesis: The Moon was formed from a large piece of the earth's crust that broke off because of centrifugal force. The result was the formation of the Pacific Ocean. This theory has been debunked because it would have required too great of a spin and the moon would be orbiting around Earth's equator.

Capture Hypothesis: The Moon was formed somewhere else in the universe. It was then captured by Earth's gravitational field and forced into orbit. This theory has also been debunked because it requires an extended atmosphere of the Earth in order to dissipate the Moon's energy, which is improbable.

Co-Formation Hypothesis: The Moon was formed at the same time as the Earth, from extra material floating around the new planet. This theory is not widely accepted because it fails to explain the absence iron in the Moon.

Giant Impact Hypothesis: The Moon was formed from an impacted between a forming Earth and a Mars sized meteor. The resulting impact filled Earth's orbit with debris from the meteor and pieces of Earth's surface. This is the most prevailing theory and computer simulations have deemed it plausible.

Answer 8

Dr. William K. Hartmann and Dr. Donald R. Davis, were the first to suggest the leading modern theory of the moon's origin, in a paper published in 1975 in the journal Icarus. It states that early in Earth's development, about 4.5 billion years old, a planetoid the size of Mars, impacted Earth at an 45 degree angle. The result was expulsion of material from the Earth and for a little while, it had a thin ring around it. Earth combined it's iron core with this planetoid, and recovered quickly due to Earth's strong gravity. The material that is in the ring around Earth, combined to form the Moon.

Answer 9

the giant impact hypothesis is currently the accepted theory. It basically says that a large asteroid collided with the earth, knocking debris from the earth into space. this debris then formed together over time to form the moon.

Answer 10

1) A Mars-sized asteroid hit the Earth when the planet was still forming and molten, and the Moon was formed from the shrapnel.

2) The Earth was rotating very quickly when it was first formed, (about the same age as the conditions for the first theory,) and the Moon spun off the Earth due to (centripetal/centrifugal, not sure which is which) force.

3) The Earth's gravity captured the Moon, which was moving through space and happened to pass by.