Question Earth Moon Origin

[skynr13]

Hello one and all
just dropped in for a sec

I wish I had a time machine.
I have been run off my feet.

OK maybe the blast from the past may have created the moon.

We should have more info in the near future.

I wonder why very few people actually believe in Darwin's idea of the Moon's creation? to me it is the most realistic!

 

[billslugg]

Darwin proposed the fission theory, where the molten Earth spun up and discharged enough material to coalesce in orbit and form the Moon. It has two problems, 1) it does not specify where the spin up energy came from. 2) Spun off material will either fall back onto the Earth or go into orbit around the Sun but cannot go into orbit around Earth. Expelled material has no way of obtaining the sideways velocity component needed to go into Earth orbit.

 

[Atlan0001]

Darwin proposed the fission theory, where the molten Earth spun up and discharged enough material to coalesce in orbit and form the Moon. It has two problems, 1) it does not specify where the spin up energy came from. 2) Spun off material will either fall back onto the Earth or go into orbit around the Sun but cannot go into orbit around Earth. Expelled material has no way of obtaining the sideways velocity component needed to go into Earth orbit.

Like all the other moons, probably, a capture rather than a material spinoff or knockoff.

 

[skynr13]

Darwin proposed the fission theory, where the molten Earth spun up and discharged enough material to coalesce in orbit and form the Moon. It has two problems, 1) it does not specify where the spin up energy came from. 2) Spun off material will either fall back onto the Earth or go into orbit around the Sun but cannot go into orbit around Earth. Expelled material has no way of obtaining the sideways velocity component needed to go into Earth orbit.

Ok, you are the first person I've talked to about this. But I really believe this theory and I won't go easily, I hope you have some physics background. What I've read about the early Earth says that it was spinning at 6 times the speed it is now or more when the Moon appeared. Would that be enough spin energy? Also if the Moon was to slowly emerge out of the Earth like a drop of water that slowly accumulates on the end of a dropper, that might be enough to keep it in orbit. The moon is moving away from us at 1 and a half inches a year and that is pretty slow compared to having a Moon emerge out of a planet. But if it emerge quicker and clung on at the end, both entities being completely molten, then in that situation it might just go into orbit. Correct?

 

[billslugg]

I studied Celestial Mechanics at the college level 53 years ago.

The escape velocity from the surface of the Earth is 11,000 m/s. A object at Earth's equator is traveling at 460 m/s. The Earth would have to be spinning 24 times faster in order to throw objects off. This is unlikely to have ever happened.

Additionally, anything thrown off the Earth returns to it. You cannot put something into orbit around an object, from the surface of that object with only one impulse of energy. What goes up must come down.

Only by putting something up there, and then giving it a sideways impulse can you put something into orbit.

 

[Atlan0001]

I studied Celestial Mechanics at the college level 53 years ago.

The escape velocity from the surface of the Earth is 11,000 m/s. A object at Earth's equator is traveling at 460 m/s. The Earth would have to be spinning 24 times faster in order to throw objects off. This is unlikely to have ever happened.

Additionally, anything thrown off the Earth returns to it. You cannot put something into orbit around an object, from the surface of that object with only one impulse of energy. What goes up must come down.

Only by putting something up there, and then giving it a sideways impulse can you put something into orbit.

A constant of velocity is always some form of constant acceleration (constant of deceleration) to play keep away from the speed of light. A splitting of dimensionality because it doesn't and can't possibly work ((t=+1), (t=-1), (c = (t=0))). What comes down must go up (per observed "accelerating expansion").

 

[skynr13]

I studied Celestial Mechanics at the college level 53 years ago.

The escape velocity from the surface of the Earth is 11,000 m/s. A object at Earth's equator is traveling at 460 m/s. The Earth would have to be spinning 24 times faster in order to throw objects off. This is unlikely to have ever happened.

Additionally, anything thrown off the Earth returns to it. You cannot put something into orbit around an object, from the surface of that object with only one impulse of energy. What goes up must come down.

Only by putting something up there, and then giving it a sideways impulse can you put something into orbit.

Ok, but in my & Darwin's theory, when the Earth was 4-4.5 billion year ago, it was spinning 6-8 times faster. Making it only necessary to spin at 4-3x faster for the Moon to reach orbit. The moon made of mostly sand and radioisotopes and the gravity on both probably reduced do to its and Earths molten state with no real atmosphere or Van Allen belt to hold things down, the idea then gets closer to the ballpark figure, having it to only 2-1.5x faster (gravity alone) and if ALL the above afor mentioned aspects are taken into account, maybe even half that at 1-.75 times faster. Also even with the moon only partially ejecting, when it started to bulge out, the added mass all on one edge could make up for this reduced figure. Then simply the high rotation and the moon rising off at a low angle from the Earth surface could be enough to giving it a sideways impulse to reach orbit insertion. (1) You are a physicist and I am not, although I understand things about rotation and centrifugal force, like when there is reduced gravity, atmosphere and both bodies are in a molten state with different composition. If you know how to calculate for these different aspects, please do and tell me what you figure out. But as you see from what I've discussed, 'Heaven isn't too far away'!
(1)-The moon lags behind the Earth's rotation. Is there a calculation that describes how fast it ejected to reach this reduced orbit speed? There are many ideas to take into account the Earth's rotation speed and that then the Moon maybe was rotating too, which could've given it extra lift.
Have a good one and keep in touch, - k.

 

[billslugg]

Your first error is in sentence two. "spin at 4-3x faster for the Moon to reach orbit." Physics does not allow this. You cannot toss something off a body and put it into orbit. You can put it up there, but it simply falls back.
I explained this in post #80. You are not paying attention. I'm moving on.

 

[Pogo]

Problem is, that if the Earth were to spin fast enough to throw off a moon-size blob because that area reached escape velocity, as the blob ascends, the escape velocity decreases with altitude, the blob continues to ascend to never return. There is nothing to slow it down to orbital speed from escape speed.

 

[Harry Costas]

Sorry
I'm just reading for now.
And work has taken too much time.

 

[Harry Costas]

[Submitted on 7 Mar 2024]

Parallel numerical simulation of impact crater with perfect matched layers​

Huacheng Li, Zongyu Yue, Nan Zhang, Jinhai Zhang, Zhongzheng Miao

Impact craters are the primary geomorphic features on the surfaces of celestial bodies such as the Moon, and their formation has significant implications for the evolutionary history of the celestial body. The study of the impact crater formation process relies mainly on numerical simulation methods, with two-dimensional simulations capable of reproducing general patterns of impact processes while conserving computational resources. However, to mitigate the artificial reflections of shock waves at numerical boundaries, a common approach involves expanding the computational domain, greatly reducing the efficiency of numerical simulations. In this study, we developed a novel two-dimensional code SALEc-2D that employs the perfect matched layer (PML) method to suppress artificial reflections at numerical boundaries. This method enhances computational efficiency while ensuring reliable results. Additionally, we implemented MPI parallel algorithms in the new code to further improve computational efficiency. Simulations that would take over ten hours using the conventional iSALE-2D code can now be completed in less than half an hour using our code, SALEc-2D, on a standard computer. We anticipate that our code will find widespread application in numerical simulations of impact craters in the future.

And this one, for your appraisal.

[Submitted on 13 Mar 2024]

Crash Chronicles: relative contribution from comets and carbonaceous asteroids to Earth's volatile budget in the context of an Early Instability​

Sarah Joiret, Sean N. Raymond, Guillaume Avice, Matthew S. Clement

Recent models of solar system formation suggest that a dynamical instability among the giant planets happened within the first 100 Myr after disk dispersal, perhaps before the Moon-forming impact. As a direct consequence, a bombardment of volatile-rich impactors may have taken place on Earth before internal and atmospheric reservoirs were decoupled. However, such a timing has been interpreted to potentially be at odds with the disparate inventories of Xe isotopes in Earth's mantle compared to its atmosphere. This study aims to assess the dynamical effects of an Early Instability on the delivery of carbonaceous asteroids and comets to Earth, and address the implications for the Earth's volatile budget. We perform 20 high-resolution dynamical simulations of solar system formation from the time of gas disk dispersal, each starting with 1600 carbonaceous asteroids and 10000 comets, taking into account the dynamical perturbations from an early giant planet instability. Before the Moon-forming impact, the cumulative collision rate of comets with Earth is about 4 orders of magnitude lower than that of carbonaceous asteroids. After the Moon-forming impact, this ratio either decreases or increases, often by orders of magnitude, depending on the dynamics of individual simulations. An increase in the relative contribution of comets happens in 30\% of our simulations. In these cases, the delivery of noble gases from each source is comparable, given that the abundance of 132Xe is 3 orders of magnitude greater in comets than in carbonaceous chondrites. The increase in cometary flux relative to carbonaceous asteroids at late times may thus offer an explanation for the Xe signature dichotomy between the Earth's mantle and atmosphere.

 

[Harry Costas]

The last sentence implies that the moon formed from a giant impact with the earth.

[Submitted on 22 Apr 2024]

Formation of the four terrestrial planets in the Jupiter-Saturn chaotic excitation scenario: fundamental properties and water delivery​

Patryk Sofia Lykawka, Takashi Ito

The Jupiter-Saturn chaotic excitation (JSCE) scenario proposes that the protoplanetary disk was dynamically excited and depleted beyond ~1-1.5 au in a few Myr, offering a new and plausible explanation for several observed properties of the inner solar system. Here, we expanded our previous work by conducting a comprehensive analysis of 37 optimal terrestrial planet systems obtained in the context of the JSCE scenario. Each optimal system harbored exactly four terrestrial planets analogs to Mercury, Venus, Earth, and Mars. We further investigated water delivery, feeding zones, and accretion history for the planet analogs, which allowed us to better constrain the water distribution in the disk. The main findings of this work are as follows: 1) the formation of four terrestrial planets with orbits and masses similar to those observed in our solar system in most of our sample, as evidenced by the dynamically colder and hotter orbits of Venus-Earth and Mercury-Mars analogs, and the high success rates of similar mutual orbital separations (~40-85%) and mass ratios of the planets (~70-90%) among the 37 systems; and 2) water was delivered to all terrestrial planets during their formation through the accretion of water-bearing disk objects from beyond ~1-1.5 au. The achievement of Earth's estimated bulk water content required the disk to contain sufficient water mass distributed within those objects initially. This requirement implies that Mercury, Venus, and Mars acquired water similar to the amount on Earth during their formation. Several of our planet analogs also matched additional constraints, such as the timing of Moon formation by a giant impact, Earth's late accretion mass and composition, and Mars's formation timescale.

 

[Harry Costas]

The search for the Origin of Earth and the moon is ongoing.

[Submitted on 23 Apr 2024]

Meteorites and Planet Formation​

Rhian H. Jones

Meteorites are a remarkable resource. They capture the imagination of people worldwide with their spectacular entry through Earth's atmosphere as fireballs, and their exotic character of being pieces of other worlds. Scientifically, they are critical to interpreting the early stages of formation of the Solar System, as well as the geological evolution of asteroids, the Moon, and Mars, and they are vital to understanding planetary formation processes. With the burgeoning exploration of extrasolar planetary systems, knowledge of the fundamental process of planetary growth from protoplanetary disks has taken on a new significance. Meteorites provide essential and detailed insight into the formation of planetary systems, although we must bear in mind that they only represent one reference point (our own Solar System) in what is clearly a wide spectrum of possible chemical and physical parameters governing the diverse realm of extrasolar planets. This chapter summarises the nature of our meteorite collections, and the ways in which meteorites contribute to our understanding of the formation and evolution of our own Solar System, with broader implications for planetary systems in general.

 

[Atlan0001]

I read somewhere a long time ago that at one time very early in Earth's physical history, Earth's spin, its day-night cycle, took just 14 hours.

 

[Classical Motion]

After this moon mating event, at what distance did the moon first settle? Was there water on the surface at this time? When oceans did appear....was the moon locked like it is today? What was the frequency and height of the first tides? Is there only a certain distance range......where an orbit can be locked? Will our moon eventually unlock?

Did the first surface life have 6 very high tides a day? Has the earth's rotation rate and the moon's period change with time? And life right along with it?

Could the rate of the light and dark frequency, effect growth rate more than just absolute time?

Life seems to accept AND advantage change....if the change is slow.

 

[Harry Costas]

Questions and questions.
All these questions require research upon research.
Yes, the Earth was much smaller.
Yes, the spin may have been faster because of the smaller size.
Water did not rest on Earth until about 4.2 billion years ago.
Evidence of that is found in Sedimentary Rocks.
Yes, the moon was formed before 4.2 billion yrs. This can be deduced by the layers of sedimentary rocks, fossil evidence and the volcanic layers.

In my opinion the Earth and the Moon were formed at the same time, locked in motions a dance played over and over.

As for the Moon formed from the collision with Earth, that is a possibility during the chaotic period within our Solar System.

 

[Harry Costas]

So! the plot thickens.
I always advice people to do more research before coming to conclusions. Never shut the door, allow for future discussions and discoveries.

[Submitted on 23 Apr 2024]

The Solar System: structural overview, origins and evolution​

Sean N. Raymond

Understanding the origin and long-term evolution of the Solar System is a fundamental goal of planetary science and astrophysics. This chapter describes our current understanding of the key processes that shaped our planetary system, informed by empirical data such as meteorite measurements, observations of planet-forming disks around other stars, and exoplanets, and nourished by theoretical modeling and laboratory experiments. The processes at play range in size from microns to gas giants, and mostly took place within the gaseous planet-forming disk through the growth of mountain-sized planetesimals and Moon- to Mars-sized planetary embryos. A fundamental shift in our understanding came when it was realized (thanks to advances in exoplanet science) that the giant planets' orbits likely underwent large radial shifts during their early evolution, through gas- or planetesimal-driven migration and dynamical instability. The characteristics of the rocky planets (including Earth) were forged during this early dynamic phase. Our Solar System is currently middle-aged, and we can use astrophysical tools to forecast its demise in the distant future.

 

[ChrisA]

In my opinion the Earth and the Moon were formed at the same time, locked in motions a dance played over and over.

As for the Moon formed from the collision with Earth, that is a possibility during the chaotic period within our Solar System.

The last two sentences can be reconciled only by a collision that was violent enough to mostly destroy the very early Earth. Then we can say that the modern Earth and Moon were created at the same time from the debris of the collision. But we can also talk about an "Earth" that was very different and must have existed before the collision and hence before the Moon. Maybe we should talk about a "proto-Earth". But we can't know much about it because all evidence of it was turned into liquid or vaporized rock by the collision.

So we can say the "modern Earth" and Moon were created at the same time and we can say that the Early Earth existed for a while before the Moon was created. There is no conflict if said that way. The Early and moden Earths were very different places.

The Early solar system was very unstable and over time became more and more stable as the mass that was in unstable orbits was either ejected to interstellar space, crashed into the Sun, or combined into bodies. What is left is perhaps the 10% or so that happened to be stable.

In a way, it was like biological evolution. Why are there no short giraffes? It is not because some of them grew longer necks. It is because the shortest ones disappeared (for lack of food.) The solar system is stable because the unstable stuff disappears (by crashing or being ejected.). We see only the surviving mass.

 

[billslugg]

If the Earth and Moon were formed from the same disc they would share the same constituents. The Moon lacks the large amount of iron we have here on Earth.

 

[Harry Costas]

What type of Iron?

The Moon has a Core and layers above.
When out Sun shed its solar envelope forming out Solar Systen. The hot Droplets giving birth to our planets and moons will have the same properties.
The information that we require to tells us the origin is yet to be discovered.

 

[Harry Costas]

It's going to take years to discover the origin of the moon

[Submitted on 9 May 2023]

Discovery of a new lunar mineral rich in water and ammonium in lunar soils returned by Chang'e-5 mission​

Shifeng Jin, Munan Hao, Zhongnan Guo, Bohao Yin, Yuxin Ma, Lijun Deng, Xu Chen, Yanpeng Song, Cheng Cao, Congcong Chai, Yunqi Ma, Jiangang Guo, Xiaolong Chen

The origin and distribution of lunar water are among the most important issues in understanding the earth-moon system. After more than half a century of laboratory research and remote detection, only hydroxyl contained minerals and lunar ice (H2O) are identified. Here we report the discovery of a hydrous mineral (NH4)MgCl3(H2O)6 in the lunar soil returned by Chang'e-5 mission, which contains 417,000 parts per million H2O. The determined structure and composition are similar to novograblenovite-a terrestrial fumarole mineral formed by reaction of hot basalt in water-rich volcanic gases, whereas the measured isotope composition delta37Cl reached 20.4 parts per thousand, a high value that only found in lunar minerals. We rule out the possibility that this hydrate originated from terrestrial contaminants or rocket exhaust through analysis of its chemical, isotopic compositions as well as the formation conditions. Our finding indicates that water can exist on some parts of the sunlit Moon in the form of hydrate compounds. Moreover, this hydrate is rich in ammonium, providing new information in understanding the origin of the Moon.

 

[Harry Costas]

Origin of the moon.
Not as simple as it may imply.


[Submitted on 2 May 2023 (v1), last revised 31 Aug 2023 (this version, v2)]

Lunar Mantle Structure and Composition Inferred From Apollo 12 -- Explorer 35 Electromagnetic Sounding​

Robert E. Grimm

Constraints on the interior of the Moon have been derived from its inductive response, principally as measured by the magnetic transfer function (TF) between the distantly orbiting Explorer 35 satellite and the Apollo 12 surface station. The most successful prior studies used a dataset spanning 0.01-1 mHz, so the lunar response could be modeled as a simple dipole. However, earlier efforts also produced transfer functions up to 40 mHz. The smaller electromagnetic skin depth at higher frequency would better resolve the uppermost mantle-where key information about primitive lunar evolution may still be preserved-but requires a multipole treatment. I compute new profiles of electrical conductivity vs depth using both low- and high-frequency ranges of published Apollo-Explorer TFs. Using the low-frequency data, I derive temperature profiles at depths >400 km (<1 mHz) consistent with conductive heat loss and expectations of the iron (and possibly water) content of the mantle. The near-constant iron fraction (Mg# 81 +/- 10) could imply efficient mixing due to now-defunct convection. Alternatively, incomplete overturn of gravitationally unstable magma-ocean cumulates could have left a heterogeneous distribution of minerals at hundred-km scales that are not resolved by electromagnetic sounding. A third explanation is that the electromagnetically probed region may be the initial equilibrium crystallization in a mantle that did not buoyantly overturn. In contrast, the high-frequency data produced higher conductivities than expected, requiring unrealistically low Mg# or high water content. Either the published transfer functions >> 1 mHz are incorrect, or the TF multipole method at the Moon is unreliable. Future electromagnetic sounding using the magnetotelluric method can operate up to 100s Hz and is largely insensitive to multipole effects, resolving structure to 100 km or less.

 

[Harry Costas]

OK we need more information.
[Submitted on 10 Jan 2023]

Constraints on the lunar core viscosity from tidal deformation​

Arthur Briaud, Agnès Fienga, Daniele Melini, Nicolas Rambaux, Anthony Mémin, Giorgio Spada, Christelle Saliby, Hauke Hussmann, Alexander Stark, Vishnu Viswanathan, Daniel Baguet

We use the tidal deformations of the Moon induced by the Earth and the Sun as a tool for studying the inner structure of our satellite. Based on measurements of the degree-two tidal Love numbers k2 and h2 and dissipation coefficients from the GRAIL mission, Lunar Laser Ranging and Laser Altimetry on board of the LRO spacecraft, we perform Monte Carlo samplings for 120,000 possible combinations of thicknesses and viscosities for two classes of the lunar models. The first one includes a uniform core, a low viscosity zone (LVZ) at the core-mantle boundary, a mantle and a crust. The second one has an additional inner core. All models are consistent with the lunar total mass as well as its moment of inertia. By comparing predicted and observed parameters for the tidal deformations we find that the existence of an inner core cannot be ruled out. Furthermore, by deducing temperature profiles for the LVZ and an Earth-like mantle, we obtain stringent constraints on the radius (500 +- 1) km, viscosity,21 (4.5 +- 0.8) x 10^16 Pa.s and the density (3400 +- 10) kg/m^3 of the LVZ. We also infer the first estimation for the outer core viscosity, (2.07 +- 1.03) x 10^17 Pa.s, for two different possible structures: a Moon with a 70 km thick outer core and a large inner core (290 km radius with a density of 6000 kg/m3), and a Moon with a thicker outer core (169 km thick) but a denser and smaller inner core (219 km radius for 8000 kg/m^3).

 

[billslugg]

"The most obvious compositional characteristic of the Moon is a deficiency of iron relative to Earth and primitive meteorites. Estimates for the bulk iron content of the Moon range from 8 to 12%, compared to 31% for Earth." - Science ,14 May 2004, p. 977, Herbert Palme

This is one of the reasons an impact hypothesis is favored. Another reason is the high amount of angular momentum in the Earth Moon system, too much to have originated by a coalescing disc.

 

[Harry Costas]

The Impact Hypothesis is in my opinion wrong.
Impact would have taken the moon in an unstable orbit, resulting coming back to earth in time.

All the evidence that we need is yet to be founded.
Wait until the cows come home for milking.

Until than we keep on researching.