Is the Moon FROM Earth?

Question

In my astronomy class, my teacher said some say billions of years ago, some big asteroid hit earth and made a big hole in earth, so big, that the piece of earth was being separated from earth, but end up orbiting earth, and over the years it cooled down, and that's how the moon was formed. They said, some parts of the moon looked like it WAS full of "volcanic or molten rock" because some looked like a spot of smooth surface except right in the center, it was a thin straight rock, or small or "mini-mountain". What's your opinion?

Answer 1

The most favored theory of where the moon came from is as you describe. A body about the size of Mars slammed into Earth not too long after it formed. The debris from that impact formed a temporary ring around our planet, then gradually reformed into a sphere that back then was only about 14,000 miles from Earth. Analysis of material brought back from the moon shows that much of it is very similar to soil and rock found on Earth. Today the moon is still receding from us at about 1.5 inches per year.

Answer 2

Not exactly sure what most of that referred to, but yes, the generally accepted theory is that the Earth was nearly destroyed by a Mars-sized asteroid early in its formation. The result was that a good chunk of the Earth's early crust was blown back into space and formed an orbiting cloud of debris around the Earth. Then according to the theory, the debris coalesced into the Moon.

Part of the reason scientists have considered this is because the Moon lacks the iron and the density you'ld expect to find in an object orbiting near the Earth. Follow the link below for more info.

Early on there was definitely volcanism on the moon, but I'm not sure if there is much left of a molten core in the moon now. One indication of this is the mare (seas). Mare started out as very large craters in the lunar surface. The craters were so large that they cracked completely through the early lunar crust, allowing some of the molten core to seep through the cracked crust and form giant lava lakes. These of course have since cooled. If you want to explore more about lunar geology, may I suggest the links below?

Answer 3

Actually, the theory say that a planetoid about the size of Mars hit the earth and BOTH were destroyed, forming a double-lobed cloud of debris from which the Earth and Moon then reformed. The cores of both planets survived, but the entire surface of each was reformed. Since "earth" had the bigger core, it reformed with more mass and managed to hold an atmosphere. The Moon, with the smaller core didn't have enough mass to reform or hold on to an atmosphere.

The planetoid that hit the young earth and formed the Earth-Moon system wasn't the only loose rock running around the early solar system, and many smaller rocks have impacted both the Earth and Moon since then. But since the Earth has an atmosphere, not only does the atmosphere absorb and burn up most of the incoming space rocks, but of the few that HAVE hit, most traces of the craters have been worn away by weather and tides. On the other hand, the moon has no atmosphere, and the craters from later rocks are easily visible to this day. Both the earth and the moon have volcanoes that have formed AFTER the impact that formed the earth and moon.

The final sentence in your question looks like the description of a typical crater on the moon. These are almost ALL formed by meteor impacts, although many of them had their floors filled with lava AFTER the impact.

Answer 4

One train of thought is that moons escaped from the planets that they revolve around early in the formation of the planet. In this scenario, a planet in a molten or gaseous state and rotating much faster would hurl off a glob of its self. As a result, the planet's rotational speed would slow and the glob, having been given orbital speed by the planet's rotation, would cool and become a moon. If this was the case, the earth would have had a hard time forming because of centrifugal force.

The asteroid theory is another train of thought. The problem with this idea is that the moon has to have been rotating at a higher rate at some point to achieve it's spherical shape. It's more possible that an asteroid or comet skipped off of the earth, which would cause it to have a high spin rate, and slowed just enough to enter the earth's orbit, and eventually become tidally locked.

More likely, because rocky planets would have eventually created heat at their cores as they became larger and larger and the compression increased, is that the earth and moon, having been given approximately the same speed by the collapsing nebula, simply attracted each other during passing.

Answer 5

I have heard this theory before and I would tend to agree with it. I can't remember what the context was, but I can recall one discussion on the subject basically stating that the Pacific Ocean was the scar left behind on the earth from where planet was impacted and the moon broken off. I don't know if I buy that completely, that after so many millions of year of reforming, volcanic upheaval, and plate tectonics that the so-called 'scar' could be so readily seen as an expanse as great as the Pacific Ocean. The comment may have had more to do with the idea of explaining the volume of the planet that was dislodged in the collision. Overall the idea of the moon being born of the earth is a sound one that stands up to scientific scrutiny.

Answer 6

Samples from the moon and measurements of its varying gravitational field have shown that it is 'lumpy' but that it is made of the same stuff as the earth, this has led to the above conclusion. Since its creation, the moon has suffered multiple impacts that have led to its pock marked apperance. Without tectonic and weathering activity (it has no core in the same way as earth) ,there has been no erosion, so you are seeing a window into the history of the cosmic bombardment that the earth has suffered in the past.

Its important to realise that this happened in the very early history of the solar system, at this time the earths crust would have barely been solid itself and there were quite a few proto planets wizzing about. A collision with something about the size of mars has been suggested, with the remains of both planetoids being absorbed into the two bodies, earth and moon.

Answer 7

The theory is supported by the fact that the moon has a very small iron core, and appears to be made mostly of the same material as the earth's mantle. If the moon had formed from the stuff that made the other planets, it should have had the same percentage of iron as they do.

Answer 8

There are several theories.None conclusively verified or proved. One of them puts the age of moon and earth at 5 billion years approximately. They were formed together when Sun shed some of its mass in the initial stages.As far as I know there is no evidevce so far or no research or papers published on the theory that you stated.