Origin of the Moon: Latest Discoveries and Theories

In summary, the latest research suggests that the Moon is most likely the same age as the Earth and was formed from the same material. Carbon dating cannot be done on Moon rocks due to the lack of organic carbon. It is possible that the Moon was once a larger planet before a collision with the Earth, but the physics of such an event make it unlikely. The composition of the Moon, with lighter elements and little iron, supports the theory that it was formed from the ejecta of a glancing collision.
  • #1
Azurite
83
0
What's the latest about the origin of the moon?

Is it true the moon is older than the earth? how?
 
Astronomy news on Phys.org
  • #2
Azurite said:
What's the latest about the origin of the moon?

Is it true the moon is older than the earth? how?
What has your research discovered so far?
 
  • #4
Moderator's note: moving thread to Astronomy & Astrophysics as it seems more likely to get useful responses there.
 
  • #5
Is there possibility the moon was a separate planet before and it decayed now with Earth being younger and exist after the moon?

Where can I get all theories and model of the moon origin?
 
  • #6
Azurite said:
Where can I get all theories and model of the moon origin?

Where have you looked already?
 
  • #7
Azurite said:
What have we really found out when we did carbon dating on the moon?

you cannot do carbon dating on moon rocks as there is no organic carbon ( living/dead plant life) with which to do carbon dating on
Azurite said:
Where can I get all theories and model of the moon origin?

google for them, BUT make sure you are reading peer reviewed research papers and not inaccurate media reports :smile:

Dave
 
  • Like
Likes phinds
  • #8
Azurite said:
Is it true the moon is older than the earth? how?

Possible, but unlikely. Earth's tectonic activity has buried the oldest rocks, so we may measure Moon rocks as being slightly older (I'm not sure if they've done this). But the Earth is likely to be just as old as the Moon, if not slightly older. Isotope ratios of various elements from the Moon are extremely close to those of the Earth, which is evidence that the Moon and the Earth were formed from the same material. If we look at samples from other planets or bodies in the solar system, we find that they all have unique isotope ratios. If the Moon had formed from a different body of material than the Earth then there should be no reason for these isotope ratios to be so similar.
 
  • Like
Likes JCMacaw, Azurite and davenn
  • #9
Drakkith said:
Possible, but unlikely. Earth's tectonic activity has buried the oldest rocks, so we may measure Moon rocks as being slightly older (I'm not sure if they've done this). But the Earth is likely to be just as old as the Moon, if not slightly older. Isotope ratios of various elements from the Moon are extremely close to those of the Earth, which is evidence that the Moon and the Earth were formed from the same material. If we look at samples from other planets or bodies in the solar system, we find that they all have unique isotope ratios. If the Moon had formed from a different body of material than the Earth then there should be no reason for these isotope ratios to be so similar.

Is it possible the material of the Earth came from the moon? The moon being much larger before and was a planet.. then something happened to the moon maybe a collision that created the Earth (being ejected from the material of the moon)? What tectonic, observational data refutes this?
 
  • #10
Azurite said:
Is it possible the material of the Earth came from the moon? The moon being much larger before and was a planet.. then something happened to the moon maybe a collision that created the Earth (being ejected from the material of the moon)?
not likely. as the Moon orbiting the Earth pretty much discounts that

Azurite said:
What tectonic, observational data refutes this?

probably none ... it's more the physics of collisions and the results thereof that most likely wouldn't allow the results we see today
Moon orbiting Earth (small body orbiting a larger body)
 
  • #11
Azurite said:
Is it possible the material of the Earth came from the moon? The moon being much larger before and was a planet.. then something happened to the moon maybe a collision that created the Earth (being ejected from the material of the moon)?

I believe davenn's explanation is correct. The physics of the collision probably don't allow for such a thing.

Azurite said:
What tectonic, observational data refutes this?

The fact that the Earth contains a substantial amount of iron in its core while the Moon does not is pretty strong evidence that the Moon came from the Earth and not vice versa. A collision shouldn't eject most of the heavy elements from an object while leaving behind mostly lighter elements. However, the opposite is certainly possible. The heavy elements sink towards the core (because of their density) while the lighter elements remain near the outside and eventually form most of the crust. A glancing collision then ejects a large amount of this outer material, which gives us a moon made up of light elements with very little heavier elements. And that's exactly what observations tell us the Moon is composed of.
 
  • Like
Likes Imager and Azurite
  • #12
Drakkith said:
The fact that the Earth contains a substantial amount of iron in its core while the Moon does not is pretty strong evidence that the Moon came from the Earth and not vice versa. A collision shouldn't eject most of the heavy elements from an object while leaving behind mostly lighter elements. However, the opposite is certainly possible. The heavy elements sink towards the core (because of their density) while the lighter elements remain near the outside and eventually form most of the crust. A glancing collision then ejects a large amount of this outer material, which gives us a moon made up of light elements with very little heavier elements. And that's exactly what observations tell us the Moon is composed of.

nice explanation ... :smile:
I should have thought of that haha :rolleyes:
 
  • Like
Likes Drakkith
  • #13
The age of the moon has been pegged at 4.51 billion years [re: http://advances.sciencemag.org/content/3/1/e1602365.full] making it slightly younger than earth, which is generally accepted to be 4.54 billion years. It is still generally believed the moon formed from debris ejected during a collision between Earth and a planet called Theia in the infant solar system. This is known as the giant impactor theory. The age of the moon was determined radiometrically through isotopes extracted from zircon crystals in rocks retrieved during the Apollo 14 mission
 
  • #14
Azurite said:
Is it possible the material of the Earth came from the moon? The moon being much larger before and was a planet.. then something happened to the moon maybe a collision that created the Earth (being ejected from the material of the moon)? What tectonic, observational data refutes this?
davenn said:
not likely. as the Moon orbiting the Earth pretty much discounts that
How is this *actually* different? If we swap the words "Earth" and "Moon" in the descriptions, has anything actually changed?

[edit] The only thing I see is that "Moon" isn't just a proper name, it is a type of object. So despite the descriptions of the event being the same, it wouldn't be correct terminology to label an object alone in its orbit to be a "moon".
 
Last edited:
  • #15
Azurite said:
Is it possible the material of the Earth came from the moon? The moon being much larger before and was a planet.. then something happened to the moon maybe a collision that created the Earth (being ejected from the material of the moon)? What tectonic, observational data refutes this?
One of the most well supported models is similar to this but the other way around.
A quite large protoplanet, about Mars sized; collided with proto Earth.
This ejected a very substantial amount of Earth's crust (if had a crust as such at that time). along with remnants of the smaller planet.
The orbiting debris then coalesced to become our Moon.
 
  • #16
Chronos said:
The age of the moon has been pegged at 4.51 billion years [re: http://advances.sciencemag.org/content/3/1/e1602365.full] making it slightly younger than earth, which is generally accepted to be 4.54 billion years. It is still generally believed the moon formed from debris ejected during a collision between Earth and a planet called Theia in the infant solar system. This is known as the giant impactor theory. The age of the moon was determined radiometrically through isotopes extracted from zircon crystals in rocks retrieved during the Apollo 14 mission

If moon came from Earth debris.. they should be same age or near

now ignoring for the moment the core concentration data... is it possible the moon has existed for the first 4.51 billion year and then the Earth came from the debris of the moon 2.5 billion years ago.. however, since it came from the moon, then the carbon dating of the materials of the Earth would still be 4.51 billion years or so (remember we only have one sample to determine the age of the moon so let's assume moon and Earth age was identical for sake of this discussion)..

so the theory is living things first evolved in the moon. Then 2.5 billion years ago.. something happened where the moon decayed (accidental or on purpose) and the materials were ejected to form a new planet (earth). Here since the material of the Earth came from the moon, the age would be identical although the Earth just formed 2.5 billion years ago.. is there any carbon dating argument that can refute this possibility (again ignoring core concentration data and others for sake of discussion)?
 
  • #17
Azurite said:
If moon came from Earth debris.. they should be same age or near

Both the Earth and the Moon have been measured as being very close to the same age. Note that these measurements are measuring the age of certain formations of rocks. The material making up the rocks existed as molten lava/magma prior to solidifying into the rocks we see today, and our measurements only date this solidification. Just because we measure a rock as being a certain age does not mean that a body isn't a bit older.

Azurite said:
now ignoring for the moment the core concentration data... is it possible the moon has existed for the first 4.51 billion year and then the Earth came from the debris of the moon 2.5 billion years ago.. however, since it came from the moon, then the carbon dating of the materials of the Earth would still be 4.51 billion years or so (remember we only have one sample to determine the age of the moon so let's assume moon and Earth age was identical for sake of this discussion)..

No. That's not possible. The melting of the material as it was ejected and then coalesced again would end up giving us an entirely different date for the formation of the Earth.

Azurite said:
so the theory is living things first evolved in the moon. Then 2.5 billion years ago.. something happened where the moon decayed (accidental or on purpose) and the materials were ejected to form a new planet (earth). Here since the material of the Earth came from the moon, the age would be identical although the Earth just formed 2.5 billion years ago.. is there any carbon dating argument that can refute this possibility (again ignoring core concentration data and others for sake of discussion)?

Yes. All radioactive dating giving us an age past 2.5 billion years ago refutes this.
 
  • #18
Drakkith said:
Both the Earth and the Moon have been measured as being very close to the same age. Note that these measurements are measuring the age of certain formations of rocks. The material making up the rocks existed as molten lava/magma prior to solidifying into the rocks we see today, and our measurements only date this solidification. Just because we measure a rock as being a certain age does not mean that a body isn't a bit older.
No. That's not possible. The melting of the material as it was ejected and then coalesced again would end up giving us an entirely different date for the formation of the Earth.
Yes. All radioactive dating giving us an age past 2.5 billion years ago refutes this.

why.. if the Earth formed 2.5 billion years ago from 4.51 billion years old material from the moon.. why would carbon dating show 2.5 billion years instead of 4.51?
 
  • #19
Azurite said:
why.. if the Earth formed 2.5 billion years ago from 4.51 billion years old material from the moon.. why would carbon dating show 2.5 billion years instead of 4.51?

Because radioactive dating relies on measuring the proportion of different isotopes of an element, or the proportion of two elements linked by radioactive decay, in a rock/mineral. For example, uranium is incorporated into the mineral zircon and decays into lead over time. However, zircon strongly rejects lead when it initially forms, so all of the lead we find inside the mineral must be from the decay of uranium. By measuring the proportion of uranium to lead we can calculate the age of the zircon.

But if I melt the zircon down and let it reform, then the lead is once again rejected, so measuring the uranium-lead ratio would give a much younger date.
 
  • #20
Azurite said:
why.. if the Earth formed 2.5 billion years ago from 4.51 billion years old material from the moon.. why would carbon dating show 2.5 billion years instead of 4.51?

I have already told you ... THERE IS NOTHING TO CARBON DATE from the moon

please understand that

and we know the Earth is older than 2.5 billion years
 
  • #21
Thread closed as the OP question has been addressed and personal speculation is out of bounds for PF.
 
  • Like
Likes davenn

1. What is the most widely accepted theory for the origin of the moon?

The most widely accepted theory for the origin of the moon is the Giant Impact Hypothesis, which proposes that the moon formed from debris left over after a Mars-sized object collided with Earth around 4.5 billion years ago.

2. What is the evidence for the Giant Impact Hypothesis?

Scientists have found several lines of evidence to support the Giant Impact Hypothesis, including similarities in the chemical composition of the moon and Earth's mantle, the moon's relatively small iron core, and the presence of moon rocks that contain traces of Earth's atmosphere.

3. How do other theories for the moon's origin differ from the Giant Impact Hypothesis?

Other theories for the moon's origin include the Fission Hypothesis, which suggests that the moon broke off from a rapidly spinning Earth, and the Capture Hypothesis, which proposes that the moon was a separate object that was captured by Earth's gravity. These theories have less supporting evidence and are not as widely accepted as the Giant Impact Hypothesis.

4. What are some recent discoveries related to the origin of the moon?

Recent discoveries include the detection of water molecules on the moon's surface, which could provide insight into the moon's formation and evolution, and the discovery of lunar rocks that are significantly older than previously thought, suggesting that the moon may have formed earlier than previously believed.

5. How do ongoing studies and missions contribute to our understanding of the moon's origin?

Ongoing studies and missions, such as the Lunar Reconnaissance Orbiter and the upcoming Artemis program, continue to gather data and samples from the moon that can help scientists better understand its origin. These missions also allow scientists to test and refine theories about the moon's formation and evolution.

Similar threads

Replies
16
Views
2K
  • Astronomy and Astrophysics
Replies
15
Views
1K
  • Astronomy and Astrophysics
Replies
21
Views
5K
  • Astronomy and Astrophysics
Replies
1
Views
1K
Replies
4
Views
484
  • Astronomy and Astrophysics
Replies
2
Views
978
  • Astronomy and Astrophysics
Replies
19
Views
1K
  • Astronomy and Astrophysics
Replies
19
Views
1K
  • Astronomy and Astrophysics
Replies
33
Views
3K
  • Astronomy and Astrophysics
Replies
2
Views
983
Back
Top