Did the core of the Earth collide with the Earth billions of years ago?

In summary, the conversation discusses the theory of the Earth's core and its origins. It is believed that the core is made up of material from outer space that collided with the Earth. This collision may have also caused plate tectonics to start. However, there are doubts about the mechanics of this collision and whether it could have happened in the way proposed. Additionally, the age of the Earth's core and the presence of water on the Moon also raise questions about this theory. Further research and evidence is needed to fully understand the formation of the Earth's core.
  • #1
verdigris
119
0
Does the core of the Earth belong to the Earth or did it come from outer space and collide with the Earth.In this scenario the volume of the moon added to the volume of the continental rocks should equal the volume of the
core ( the collision would have displaced material from inside the Earth).And could such a collision have fractured the Earth's surface starting plate tectonics?
 
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  • #2
ALL of the mass of the Earth came from "outer space".
 
  • #3
verdigris said:
And could such a collision have fractured the Earth's surface starting plate tectonics?

I'm not too familiar with the theory of collision of a large body with the early earth, but I thought that the theory went that the Earth was pretty much melted, rather than fractured. Plate fracturing doesn't seem to need any impact to start it off today, so I doubt that it would be nessecary on the early crust, which was most likely quite a bit thinner.
 
  • #4
The collision would have had to have been at a precise angle or else the extra momentum imparted to the Earth would have made it leave the solar system or go into the Sun.This makes a collision on this scale seem unlikely in itself.
 
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  • #5
Well I think it would probably be agreed that some of the core came from early impacts, if you're suggesting that we were hit by a large ball of iron that eventually found its way down to the centre of the Earth then no, that didn't happen.

A large impact would have melted (some of) the Earth by the mechanism of decompressional melting, caused by a phase of decompression immediately following the impact. It is actually thought that this would cause a plume in the upper mantle, perhaps somehow this helped get plate tectonics going?
 
  • #6
Any large collision that an iron core could have had with the Earth to cause the moon to form would have had to have taken place more than 3 billion years ago (water has been on Earth for 3 billion years) or else we would expect there to be a lot of water removed from the Earth on the moon and floating around in the path of Earth's orbit as blocks of ice.There is not and the core is only 2.5 billion years old.Also there is the unlikeliness of a precise angle of attack by a large projectile (to stop the Earth going out of orbit of the sun),so I suspect the Earth and moon formed side by side in space.
 
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  • #7
Further evidence against a core colliding with Earth is that we would expect
water to have been ejected from the oceans into space,and this would mean that the ratio of deuterium/ normal hydrogen would be bigger in the sea than is
observed (deuterium is heavier than normal hydrogen and so less water containing it would get the velocity required to escape from the Earth).
 
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  • #8
verdigris said:
Any large collision that an iron core could have had with the Earth to cause the moon to form would have had to have taken place more than 3 billion years ago (water has been on Earth for 3 billion years) or else we would expect there to be a lot of water removed from the Earth on the moon and floating around in the path of Earth's orbit as blocks of ice.
Or it might have collected on the moon, in fact there are people who believe that the record of some of Earth's larger impacts might be preserved on the moon (which itself is generally thought to be the record of a very large impact), this is an interesting prospect indeed as a lot of the evidence on our own planet of past impacting events has been lost by resurfacing processes.

the core is only 2.5 billion years old.
Is it? I didn't know that, can you please back that statement up.

Also there is the unlikeliness of a precise angle of attack by a large projectile (to stop the Earth going out of orbit of the sun),so I suspect the Earth and moon formed side by side in space.
The energy from the moon forming impact is thought to have been converted into the angular momentum that the Earth moon system has as a whole as well as providing energy for the Earth's rotation -which is why we have days! Again, this statement seems rather bold, did you come up with that off the top of your head or have you seen some kind of study which comes to this conclusion.


verdigris said:
Further evidence against a core colliding with Earth is that we would expect water to have been ejected from the oceans into space,and this would mean that the ratio of deuterium/ normal hydrogen would be bigger in the sea than is observed (deuterium is heavier than normal hydrogen and so less water containing it would get the velocity required to escape from the Earth).
Again I didn't know that, have you got a reference?
 
  • #9
verdigris said:
The collision would have had to have been at a precise angle or else the extra momentum imparted to the Earth would have made it leave the solar system or go into the Sun.This makes a collision on this scale seem unlikely in itself.

The amount of energy needed to lift the Earth out of the solar system would have vaporized both objects. And to direct the Earth into the sun, the impact would have to be at a precise angle. I would have expected a major collision to result in a strongly elliptical orbit.

I get your point though, that we might expect a major collision to alter the orbit in some dramatic way. But astronomers do think the moon was formed by collision. I don't understand the mechanics either. I know our orbit is slightly elliptical, but not by much.

Here are my first 4 hits on a Google search for "formation of the moon"

http://csep10.phys.utk.edu/astr161/lect/moon/moon_formation.html
http://www.psi.edu/projects/moon/moon.html
http://www.windows.ucar.edu/tour/link=/earth/moon/moon_evolution_overview.html
http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question38.html
 
  • #10
BillJx said:
I get your point though, that we might expect a major collision to alter the orbit in some dramatic way. But astronomers do think the moon was formed by collision. I don't understand the mechanics either. I know our orbit is slightly elliptical, but not by much.
[/url]

Our orbit was altered in a dramatic way, we now orbit the moon as well as the Sun.
 
  • #11
billiards said:
Our orbit was altered in a dramatic way, we now orbit the moon as well as the Sun.

That's a great answer Mr B! It ducks the question though I think. Or maybe not. I guess what I'm really talking about is the orbit of the Earth-moon pair as the resultant momentum vector of the collision. Doesn't it have to be radically different from the pre-collision vector of the Earth alone? Not that we would know what that was, but I still don't get why the orbit is so well behaved.

I know I'm missing something and I suspect it has to do with rotational momentum . . . ? Or maybe the momentum of the orbiting Earth is so great that the impact had less effect than I imagine.
 

1. What evidence suggests that the core of the Earth collided with the Earth billions of years ago?

Scientists have found evidence in the form of seismic waves, magnetic fields, and geological features that indicate the Earth's core has undergone a major impact in the past. For example, the presence of a large iron-nickel core, the Earth's tilted magnetic field, and the distribution of certain elements in the Earth's crust all point to a collision event.

2. How long ago did the collision between the Earth and its core occur?

The exact timing of the collision is still debated among scientists, but it is estimated to have occurred around 4.5 billion years ago, during the formation of the Earth. This is based on the age of the Earth and the timing of other major events in the solar system's history.

3. What was the impact of the Earth's core colliding with the Earth?

The collision between the Earth and its core had a major impact on the Earth's structure and composition. It is believed that the impact caused the Earth's core to separate from its crust and mantle, forming distinct layers. It also contributed to the formation of the Earth's magnetic field and influenced the distribution of elements on the surface of the Earth.

4. Could a collision between the Earth and its core happen again?

It is highly unlikely that a collision between the Earth and its core could occur again. The Earth's core is currently stable and the likelihood of another planet-sized object colliding with the Earth is very low. However, smaller impacts from asteroids or comets are still possible and have happened in the past.

5. How does the collision between the Earth and its core impact life on Earth?

The collision between the Earth and its core played a crucial role in creating the conditions necessary for life to develop on Earth. It helped to create the Earth's unique magnetic field, which protects the planet from harmful solar radiation. It also influenced the distribution of elements on the Earth's surface, which are essential for the development of life. Without this collision, life on Earth as we know it may not have been possible.

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