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The Moon (Earth's Moon)

... One of the most remarkable lunar anomalies is it's strange field of gravity.It has feature known as mascons - mass concentrations - where gravity is stronger.This does not necessarily mean that there are huge voids under the surface ( left by migration of the mass that should have been there to the mascons?)
but it's fair to say there is something very strange indeed about the Moon's structure. ...
 
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There are some up-to-date, quite detailed models of the lunar interior, Ive seen on the 'net. The mascons seem to be broken-away pieces of the crust which are suspended in the magma, at depths at which voids would be impossible.
However the papers with these models don't seem to be available on the net at the moment. If I find one I'll link to it.
 
The Moon just keeps getting weirder. It's has a sufficiently violent geological past for chunks of the crust to break off and get submerged in the magma, yet not hot enough to melt them down.

http://www.cmf.nrl.navy.mil/cgi-bin/cle ... ter=415_nm.[/url]

This is a link to the Clementine Lunar Image Browser. The coordinates are: minus 35 lat., 208 long. Resolution 1 pixel per km, 768x768. Not directly relevant but interesting nonetheless !
 
eburacum said:
There are some up-to-date, quite detailed models of the lunar interior, Ive seen on the 'net. The mascons seem to be broken-away pieces of the crust which are suspended in the magma, at depths at which voids would be impossible.
However the papers with these models don't seem to be available on the net at the moment. If I find one I'll link to it.

Damn, I was hoping it was due to the black monolith buried in Tycho Crater...
 
Bigfoot73 said:
The Moon just keeps getting weirder. It's has a sufficiently violent geological past for chunks of the crust to break off and get submerged in the magma, yet not hot enough to melt them down.
The prevailing hypothesis today is that the Earth–Moon system formed as a result of a giant impact. A Mars-sized body (labelled "Theia") is hypothesized to have hit the proto-Earth, blasting sufficient material into orbit around the proto-Earth to form the Moon through accretion.[4]

http://en.wikipedia.org/wiki/The_moon#Formation
Hardly surprising it's a bit lumpy, then. 8)
 
Indeed not. Might also go some way toward explaining the suspected lack of a molten core.
Could also indicate a geology weird enough to produce underground cavities.
 
rynner2 said:
Bigfoot73 said:
The Moon just keeps getting weirder. It's has a sufficiently violent geological past for chunks of the crust to break off and get submerged in the magma, yet not hot enough to melt them down.
The prevailing hypothesis today is that the Earth–Moon system formed as a result of a giant impact. A Mars-sized body (labelled "Theia") is hypothesized to have hit the proto-Earth, blasting sufficient material into orbit around the proto-Earth to form the Moon through accretion.[4]

http://en.wikipedia.org/wiki/The_moon#Formation
Hardly surprising it's a bit lumpy, then. 8)

That hypothesis is now in doubt because the circularity of the moons orbit suggests that the collision would have to have been almost impossibly glancing which isn't consistant with the state of the solar system at that time.If the collision had been more head on as is more likely then the resulting orbit of the moon would be more elliptical.
 
rynner2 said:
The prevailing hypothesis today is that the Earth–Moon system formed as a result of a giant impact. A Mars-sized body (labelled "Theia") is hypothesized to have hit the proto-Earth, blasting sufficient material into orbit around the proto-Earth to form the Moon through accretion.[4]

http://en.wikipedia.org/wiki/The_moon#Formation
Hardly surprising it's a bit lumpy, then. 8)

KarlD said:
That hypothesis is now in doubt because the circularity of the moons orbit suggests that the collision would have to have been almost impossibly glancing which isn't consistant with the state of the solar system at that time.If the collision had been more head on as is more likely then the resulting orbit of the moon would be more elliptical.

The 'impossibly glancing' blow is probably explained by a collision with a Mars-sized impactor which had formed in the Earth/Sun Lagrange L4 point. Such an object would have approached Earth in practically the same orbit as the Earth itself. A glancing blow at relatively low speed would then result in the formation of the Moon in a circular orbit.

A similar formation hypothesis has been put forward for the formation of Pluto and Charon, which are in reasonably circular orbits around each other.
 
Talking about underground cavities on the Moon ... here's a possible hole into one

http://www.newscientist.com/article/dn1 ... -moon.html

A deep hole on the moon that could open into a vast underground tunnel has been found for the first time. The discovery strengthens evidence for subsurface, lava-carved channels that could shield future human colonists from space radiation and other hazards.

The moon seems to possess long, winding tunnels called lava tubes that are similar to structures seen on Earth. They are created when the top of a stream of molten rock solidifies and the lava inside drains away, leaving a hollow tube of rock.

Their existence on the moon is hinted at based on observations of sinuous rilles – long, winding depressions carved into the lunar surface by the flow of lava. Some sections of the rilles have collapsed, suggesting that hollow lava tubes hide beneath at least some of the rilles.

But until now, no one has found an opening into what appears to be an intact tube. "There's sort of a chicken-and-egg problem," says Carolyn van der Bogert of the University of Münster in Germany. "If it's intact, you can't see it."

Finding a hole in a rille could suggest that an intact tube lies beneath. So a group led by Junichi Haruyama of the Japanese Aerospace Exploration Agency searched for these "skylights" in images taken by Japan's Kaguya spacecraft, which orbited the moon for almost two years before ending its mission in June.

Deep cave
The team found the first candidate skylight in a volcanic area on the moon's near side called Marius Hills. "This is the first time that anybody's actually identified a skylight in a possible lava tube" on the moon, van der Bogert, who helped analyse the feature, told New Scientist.

The hole measures 65 metres across, and based on images taken at a variety of sun angles, the the hole is thought to extend down at least 80 metres. It sits in the middle of a rille, suggesting the hole leads into a lava tube as wide as 370 metres across.

It is not clear exactly how the hole formed. A meteorite impact, moonquakes, or pressure created by gravitational tugs from the Earth could be to blame. Alternatively, part of the lava tube's ceiling could have been pulled off as lava in the tube drained away billions of years ago.

Radiation shield
Finding such an opening could be a boon for possible human exploration of the moon (see What NASA's return to the moon may look like).

Since the tubes may be hundreds of metres wide, they could provide plenty of space for an underground lunar outpost. The tubes' ceilings could protect astronauts from space radiation, meteoroid impacts and wild temperature fluctuations (see Can high-tech cavemen live on the moon?).

"I think it's really exciting," says Penny Boston of the New Mexico Institute of Mining and Technology in Socorro. "Basalt is an extremely good material for radiation protection. It's free real estate ready to be exploited and modified for human use."

Blocked passage?
But even if astronauts were to rappel into the hole, they might not be able to travel far into the tube it appears to lead into. "I would bet a lot of money that there's a tube there, but I would not bet nearly so much that we could gain access to the tube," says Ray Hawke of the University of Hawaii at Manoa, who has also hunted for lunar lava tubes.

Rubble or solidified lava might block up the tube. "It could be closed up and inaccessible," Hawke told New Scientist.

NASA's Lunar Reconnaissance Orbiter (LRO), which should be able to snap images of the area that are at least 10 times as sharp, could help reveal more about the hole. And more lava tube openings may be found.

The Kaguya team is still combing over images of other areas in search of additional skylights. And Hawke says a proposal is in the works to use LRO's main camera to snap oblique shots of the lunar surface. This could help reveal cave entrances that are not visible in a bird's-eye view.

Journal reference: Geophysical Research Letters (in press)
Similar things have been seen on Mars. The low gravity seems to allow unusually large lava tubes on both worlds- in theory, I suppose the lava tubes on the Moon could be proportionally larger due to the lower gravity.
 
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Images & comments at link.

Interview: NASA Scientist's Plan to Extract Moon Water Affordably Using Microwaves
http://www.popsci.com/technology/articl ... -appliance
By Sandeep Ravindran Posted 10.29.2009 at 1:30 pm 9 Comments


Ed Ethridge courtesy NASA

Last month, scientists confirmed the widespread presence of small amounts of water on the moon. This landmark finding was followed by NASA's crashing its LCROSS probe into a crater in the lunar south pole, generating data which is currently being analyzed to determine the extent of water present around the impact site. Water extracted from the lunar soil could be used to sustain life and to generate rocket propellant. PopSci.com spoke to Ed Ethridge of NASA's Marshall Space Flight Center, who has been studying how microwaves could be used to extract water from lunar soil.

Why use microwaves?

The thermal conductivity of the moon's soil is very low, which was something that the Apollo astronauts found. So we can't heat the soil just by shining the sun's rays on it, they would just get reflected. The advantage of microwaves is that they penetrate and heat the soil from the inside.

How do you then extract the water?

The microwaves don't actually heat the ice, they heat the soil. But the water molecules get hot, and at around -60 Fahrenheit the water turns directly from ice to vapor. We could use a cold trap above the soil to turn the vapor back into liquid water and collect it.

And you tested this experimentally?

Yes, along with Bill Kauckler of the University of Alabama-Huntsville. We were trying to get funding for a vacuum chamber, which is really expensive, when Bill pointed out that we didn't really need something that large. So we just put cryogenically cooled lunar soil simulant in a vacuum vessel, and put it in a regular microwave that we modified. And just as we expected the soil heated up, the water turned to vapor, and we were able to collect the water using a cold trap.

How have you followed up that research?

Well, to use more powerful microwaves in the megahertz or gigahertz range would require tens of thousands of dollars. The hardware is available, but it is very expensive. NASA's In-Situ Research Utilization (ISRU) project has a minuscule budget, so it's hard to build prototype hardware like that. So instead we've been using the Comsol multiphysics modeling tool, to model the many variables. Comsol can give us pretty reasonable calculations about how deep microwaves can penetrate at different wavelengths, and the rate at which the water will come out when we heat it up. Once we have more theoretical data, we can build a prototype to target a specific purpose. We're also hoping to get actual lunar soil to test it on; right now we create lunar soil simulants that mimic the soil from different parts of the moon.

How do NASA's recent findings impact your research?

Apart from the fact that there's water on the moon, the data will help us find out where the water is. NASA's lunar prospector showed us some subtle data aspects, like indicating that the top surface of the poles, anywhere from 4 to 40 inches of the soil, is water depleted. So we may need the microwaves to penetrate 40 inches into the soil. More data could help us find out exactly how deep the water is. Also, what's its concentration? Some estimates indicate that water may form 1-2 percent of the soil. But others say it's as high as 40 percent, in which case the water would fill up all the interstices of the soil. This would make mining it very tough, since the soil would be as hard as granite at the temperatures found on the moon. Microwaves would have many advantages: they're simple, and we can heat the water in situ to extract it.

Microwaving Moon Dust: courtesy NASA

http://www.popsci.com/technology/articl ... -appliance
 
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Was the moon created by a nuclear explosion on Earth?
By Daily Mail Reporter
Last updated at 8:33 AM on 29th January 2010

How the Moon was created and came to orbit the Earth has long puzzled scientists.
The most commonly held theory is that when the solar system was first formed, an object collided with Earth, knocking off a chunk of rock that fell into orbit around it.
But now two scientists have come up with a new explanation. They believe the Moon did not break away from the Earth because of an impact or an explosion in space, but because of a nuclear explosion on Earth itself.

Their idea is based on the fission theory which was first outlined in the 19th century.

The fission theory suggested that the Earth and Moon were both created out of the same blob of spinning molten rock - with a part becoming separated which later became the moon.
However, aside from an impact, scientists couldn't explain how the blob which became the moon spun off.

Rob de Meijer at University of the Western Cape and Wim van Westrenen at VU University in Amsterdam believe the moon was blasted out of the Earth by a nuclear explosion on our planet.

In their research paper, 'An alternative hypothesis for the origin of the Moon', they explain that if the moon had been separated from the Earth by an impacting external force, the moon would be composed of whatever knocked into it and the Earth.
'Models of solar system evolution show that it is highly unlikely for the chemical composition of the Earth and impactor to be identical,' they state.

Yet recent lunar samples show that the moon is almost identical in chemical composition to the Earth - suggesting there was no impactor involved.
'A more likely possibility for the large degree of compositional similarity... is that the moon derives directly from terrestrial material,' the research paper states.

They believe that the energy that caused the moon to break into orbit around Earth was 'supplied by a supercritical georeactor in Earth’s core-mantle boundary producing sufficient heat to vaporize and eject part of the bulk silicate earth'.

Clay Dillow from Popular Science supports the theory. He states: 'According to their explanation, the centrifugal forces on Earth concentrated heavier elements like uranium and thorium near the surface around the equatorial plane.

'Enough of these elements in high enough concentrations could set off a runaway nuclear chain reaction, similar to the kind that cause nuke plant meltdowns.

'In this way, a natural-born nuclear georeactor was pushed to supercritical levels and: BOOM! The moon was cleaved from the Earth and rocketed into orbit by a massive nuclear explosion.
'It’s a tough theory to test, but we do know that nuclear georeactors existed, their legacy left behind in the uranium we mine from the Earth today. '

De Meijer and van Westrenan conclude that proving their theories will depend on future moon missions returning lunar samples from greater depths

Read more: http://www.dailymail.co.uk/sciencetech/ ... z0dzvJlJqi
 
Moon has liquid core just like Earth... reveal sensors left on lunar surface by astronauts 40 YEARS ago
By Graham Smith
Last updated at 1:16 PM on 7th January 2011

It's an unlikely marriage between state-of-the-art and 40-year-old technology that has yielded extraordinary results.

Signals from seismic sensors left on the lunar surface by Apollo astronauts in 1971 have revealed that the Moon has a liquid core similar to Earth's.
Scientists at Nasa applied contemporary seismological techniques to the data being emitted from sensors placed by their colleagues during the U.S. space program's heyday.

The new research suggests the Moon possesses a solid, iron-rich inner core with a radius of nearly 150 miles and a fluid, primarily liquid-iron outer core with a radius of roughly 205 miles.

Where it differs from Earth is a partially molten boundary layer around the core estimated to have a radius of nearly 300 miles.
The data sheds light on the evolution of a lunar dynamo - a natural process by which our Moon may have generated and maintained its own strong magnetic field.

Uncovering details about the lunar core is critical for developing accurate models of the Moon’s formation.

The core contains a small percentage of light elements such as sulphur, echoing new seismology research on Earth that suggests the presence of light elements - such as sulphur and oxygen - in a layer around our own core.
The research, published in the online edition of journal Science, used extensive data gathered during the Apollo-era Moon missions.

The Apollo Passive Seismic Experiment consisted of four seismometers deployed between 1969 and 1972, which recorded continuous lunar seismic activity until late 1977.
Dr Renee Weber, lead researcher a Nasa’s Marshall Space Flight Center in Huntsville, Alabama, said: 'We applied tried and true methodologies from terrestrial seismology to this legacy data set to present the first-ever direct detection of the Moon’s core.'

The team also analysed Apollo lunar seismograms using array processing, techniques that identify and distinguish signal sources of moonquakes and other seismic activity.

The researchers identified how and where seismic waves passed through or were reflected by elements of the Moon’s interior, signifying the composition and state of layer interfaces at varying depths.
Although sophisticated satellite imaging missions to the Moon made significant contributions to the study of its history and topography, the deep interior of Earth’s sole natural satellite remained a subject of speculation and conjecture since the Apollo era.

Scientists had previously inferred the existence of a core, based on indirect estimates of the Moon’s interior properties, but many disagreed about its radius, state and composition.

A primary limitation to past lunar seismic studies was the wash of 'noise' caused by overlapping signals bouncing repeatedly off structures in the Moon’s fractionated crust.
To mitigate this challenge, Dr Weber and her team employed an approach called seismogram stacking, or the digital partitioning of signals.
Stacking improved the signal-to-noise ratio and enabled the researchers to more clearly track the path and behaviour of each unique signal as it passed through the lunar interior.

Dr Weber said: 'We hope to continue working with the Apollo seismic data to further refine our estimates of core properties and characterise lunar signals as clearly as possible to aid in the interpretation of data returned from future missions.'
Future Nasa missions will help gather more detailed data. The Gravity Recovery and Interior Laboratory - or GRAIL - is a Nasa Discovery-class mission set to launch this year.

The mission consists of twin spacecraft that will enter tandem orbits around the Moon for several months to measure the gravity field in unprecedented detail.

It will also answer long-standing questions about Earth’s moon and provide scientists a better understanding of the satellite from crust to core, revealing subsurface structures and, indirectly, its thermal history.

Read more: http://www.dailymail.co.uk/sciencetech/ ... z1ARN4RdPm
 
interesting!
I wonder what the red dots are in this image?
article-1344980-0CAD3E15000005DC-796_468x467.jpg

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Water in the Sea of Tranquillity? Oh yes there is...
Scientists believe the interior of the Moon is very similar to that of Earth, with an abundance of water below its surface
By Steve Connor, Science Editor
Friday, 27 May 2011

The good news for any future lunar mission is that the Moon has about 100 times as much water as previously estimated. The bad news is that each of these water molecules is locked inside tiny volcanic crystals and so is unlikely to be of any use to visiting astronauts in need of a drink.

Scientists analysing tiny grains of lunar rock brought back by the Apollo 17 mission in 1972 have found a remarkable similarity in terms of water content between the Earth's upper mantle and the Moon. Instead of the Moon being largely water-free beneath its barren surface, it appears to be just as watery as the underground rocks found on Earth, they said.

The discovery of similar quantities of water caged inside the volcanic crystals of lunar rock lends further support to the idea that the Moon was created when a massive chunk of the early Earth became separated from is mother planet in a cataclysmic event about 4.5 billion years ago.

But paradoxically the presence of the lunar water casts doubt on the idea that this event was a massive collision between the early Earth and another Mars-sized planet. If such an event had indeed created the Moon, as scientists had previously supposed, all of the lunar water should have been vapourised in the process.

Despite the perplexing problems created by the latest discovery, the researchers behind the find are hailing it as an important breakthrough in the understanding of the Earth's only natural satellite, a moon that is in fact much bigger in proportion to its orbiting planet than most of the other moons of the Solar System. "These samples provide the best window we have to the amount of water in the interior of the Moon," said Professor James Van Orman of Case Western Reserve University in Cleveland, Ohio. "The interior seems to be pretty similar to the interior of the Earth, from what we know about water abundance."

Nasa scientists had already shown that large amounts of frozen water exist at the bottom of craters at the lunar poles, which are kept in perpetual shadow and so well below freezing point. They suggested that this water was deposited by passing comets, but the latest study published in the journal Science hints that they could also have arisen from past volcanic eruptions of lunar magma oozing up to the lunar surface.

The relatively large size of the Moon compared to Earth is one of the factors suggesting that it resulted from an early impact with another passing planet. Other evidence of the Moon's creation during a massive impact comes from the fact that it lacks iron, like the iron-depleted mantle of the Earth from which it is supposed to have formed.

Another supporting piece of evidence comes from the oxygen isotopes found on the Earth and the Moon, which are similar in proportion to one another, and unlike those of Mars and meteorites. But if the Moon is indeed a massive chunk of the Earth, the problem of how it came to be created without a giant impact still remains a mystery of space.

http://www.independent.co.uk/news/scien ... 89702.html
 
Earth may once have had two moons
By Matt McGrath, Science reporter, BBC World Service

A new theory suggests the Earth once had a small second moon that perished in a slow motion collision with its "big sister".
Researchers suggest the collision may explain the mysterious mountains on the far side of our Moon.
The scientists say the relatively slow speed of the crash was crucial in adding material to the rarely-seen lunar hemisphere.
Details have been published in the journal Nature.

The researchers involved hope that data from two US space agency (Nasa) lunar missions will substantiate or challenge their theory within the next year.

For decades, scientists have been trying to understand why the near side of the Moon - the one visible from Earth - is flat and cratered while the rarely-seen far side is heavily cratered and has mountain ranges higher than 3,000m.
Various theories have been proposed to explain what's termed the lunar dichotomy. One suggests that tidal heating, caused by the pull of the Earth on the ocean of liquid rock that once flowed under the lunar crust, may have been the cause.

But this latest paper proposes a different solution: a long-term series of cosmic collisions.
The researchers argue that the Earth was struck about four billion years ago by another planet about the size of Mars. This is known as the global-impact hypothesis. The resulting debris eventually coalesced to form our Moon.

But the scientists say that another, smaller lunar body may have formed from the same material and become stuck in a gravitational tug of war between the Earth and the Moon.

Dr Martin Jutzi from the University of Bern, Switzerland, is one of the authors of the paper. He explained: "When we look at the current theory there is no real reason why there was only one moon.
"And one outcome of our research is that the new theory goes very well with the global impact idea."

After spending millions of years "stuck", the smaller moon embarked on a collision course with its big sister, slowly crashing into it at a velocity of less than three kilometres per second - slower than the speed of sound in rocks.

Dr Jutzi says it was a low velocity crash: "It was a rather gentle collision at around 2.4km per second; lower than the speed of sound - that's important because it means no huge shocks or melting was produced.

At the time of the smash, the bigger moon would have had a "magma ocean" with a thin crust on top.
The scientists argue that the impact would have led to the build-up of material on the lunar crust and would also have redistributed the underlying magma to the near side of the moon, an idea backed up by observations from Nasa's Lunar Prospector spacecraft.

In a commentary, Dr Maria Zuber from the Massachusetts Institute of Technology (MIT) in Cambridge, US, suggests that while the new study "demonstrates plausibility rather than proof", the authors "raise the legitimate possibility that after the giant impact our Earth perhaps fleetingly possessed more than one moon".

The researchers believe one way of proving their theory is to compare their models with the detailed internal structure of the moon that will be obtained by Nasa's Lunar Reconnaissance Orbiter.
They will also be looking to high resolution gravity mapping set to be carried out next year by the Gravity Recovery and Interior Laboratory (GRAIL) mission.

But according to Dr Jutzi the scientists would prefer to get their hands on samples from the far side of the Moon to prove their theory.
"Hopefully in future, a sample return or a manned mission would certainly help to say more about which theory is more probable."

http://www.bbc.co.uk/news/science-environment-14391929
 
Moon formation: New spins put on old questions

Scientists have put a new turn on the theory of how the Moon was created.
It has long been thought that the lunar body resulted from an impact between the early Earth and another planet-sized object 4.5 billion years ago.
But this theory predicts Earth and its satellite should have a quite different chemical make-up - and the data shows in fact they are very similar.

Now, new modelling reveals that if the Earth had a much faster spin before the impact, the theory fits the chemistry.
It is one idea to fix the composition conundrum explored in two papers published this week by the journal Science.

The giant impact hypothesis was first posited in the 1970s. It holds that the Moon formed from the debris kicked into orbit by the collision of a smaller proto-planet with the infant Earth.
But the early models indicated that much of this debris would have originated from the impactor, whose composition would most probably have differed substantially from that of Earth.
This is not reflected in the analysis of Earth and Moon rocks – for example, their oxygen isotope, or atom type, compositions are identical.

Matija Cuk, from the Seti Institute, and colleagues ran new simulations in which the early Earth was rotating on its axis in just a few hours prior to the impact - compared to the present 24 hours.
In such a scenario, the team could get debris material thrown into a Moon-forming disc around the Earth that had the right chemical make-up. In other words, it was substantial Earth material from its mantle that was ejected in the collision.
After the impact, the gravitational interaction between the Sun and the Moon could then have slowed the fast rotation of the Earth to the speed we now experience.

Robin Canup from the Southwest Research Institute (SwRI) and colleagues took a different approach.
Their simulations involved larger impactors hitting an Earth of comparable size and at comparatively lower speeds. Again, the team was able to produce a Moon with the same chemical composition as the Earth.

http://www.bbc.co.uk/news/science-environment-19992233
 
Moon formed from merger of 20 little ‘moonlets’, new theory suggests
Sarah Knapton, Science Editor
9 January 2017 • 5:13pm

The Moon may have formed through the merging of 20 smaller ‘moonlets’ following asteroid strikes on the young Earth, a new theory suggests.

The formation of the Moon has always remained something of a puzzle for scientists.
The main theory, which has held sway since the 1970s, is known as the ‘Giant Impact’ theory and suggests that a Mars-sized object named Theia smashed into Earth around 4.31 billion years ago, knocking a huge cloud of debris into space which eventually coalesced to form the Moon.

But there are problems with this scenario. Chemical analyses of Moon rock brought back by astronauts shows it is nearly identical to that of the Earth.
In other words, there is no trace of the large body that supposedly hit Earth.

Now researchers in Israel have offered a solution. They suggest that if the Earth had been bombarded by a number of smaller asteroid strikes it could have allowed smaller ‘moonlets’ to form from Earth’s debris which merged over time.
It means that the Moon we see every night is not Earth’s first moon, but rather the last in a series of moons that orbited the Earth in the past

“Our model suggests that the ancient Earth once hosted a series of moons, each one formed from a different collision with the proto-Earth,” said co-author Dr Hagai Perets of the Technion (Israel Institute of Technology)
“It’s likely that such moonlets were later ejected, or collided with the Earth or with each other to form bigger moons.
“We believe the Earth had many previous moons, a previously formed moon could therefore already exist when another moon-forming giant impact occurred.”

To check the conditions for the formation of such mini-moons or moonlets the researchers ran 800 simulations of impacts with the Earth.
[Diagrams]

The collisions – which could have been with different sized space rocks – would have sent clouds of rubble, melt and vapor into orbit around the early Earth.
These, according the simulations the scientists created, would have cooled and agglomerated into small moonlets that, in time, could have merged into one.

Small, high-velocity collisions could also mine more material from Earth than a single, large one, the scientists claim, accounting for why there is no evidence of the strike asteroids.

And if a number of different bodies collided with Earth over a period of millions of years, their different chemical signatures – for example, ratios of oxygen-16 to its heavier cousins, oxygen-17 and -18 – might even out, masking the traces of the various collisions.

The tidal forces from the Earth could have caused the moonlets to slowly migrate outwards in the same way that the current Moon is moving at a pace of about 1 cm a year.
A pre-existing moon would slowly move out by the time another moon forms. However, their mutual gravitational attraction would eventually cause the moons to affect each other, and change their orbits.

Dr Gareth Collins of the Department of Earth Science & Engineering at Imperial College said: “The paper shows they show how a Moon that is formed largely out of Earth-derived material may be a more natural consequence of building the Moon from a number of moonlets, formed by a series of large impacts, rather than in one go.
“Since it was proposed in the mid-1970s, the giant-impact hypothesis has become the favoured explanation for how the Moon was born.

“The team has revived the hitherto largely discarded scenario that a series of smaller and more common impacts, rather than a single giant punch, formed the Moon.
“For final adjudication, we must now look for firmer evidence on each side.

The research was published in the journal Nature Geoscience.

http://www.telegraph.co.uk/science/...erger-20-little-moonlets-new-theory-suggests/
 
New research indicates the moon is "a little" younger than previously believed. Given the cosmic timescale, "a little" means on the order of 85 million years.
The moon is 85 million years younger than previously thought

It turns out the moon is a little younger than scientists previously thought — about 85 million years younger, to be precise.

In a new study, researchers at the German Aerospace Center found out that, not only did the moon once have a massive, fiery magma ocean, but our rocky satellite also formed later than scientists previously expected.

Billions of years ago, a Mars-size protoplanet smashed into the young Earth and, amid the debris and cosmic rubble, a new rocky body formed — our moon. In this new work, the researchers reconstructed the timeline of the moon's formation. While scientists have previously thought that this moon-forming collision happened 4.51 billion years ago, the new work pegged the moon's birth at only 4.425 billion years ago. ...

FULL STORY: https://www.livescience.com/moon-85-million-years-younger-than-thought.html
 
Here are the bibliographic details and abstract for the newly published resaerch indicating the moon is younger than we thought ...

A long-lived magma ocean on a young Moon
M. Maurice, N. Tosi, S. Schwinger, D. Breuer and T. Kleine
Science Advances 10 Jul 2020:
Vol. 6, no. 28, eaba8949
DOI: 10.1126/sciadv.aba8949
Abstract
A giant impact onto Earth led to the formation of the Moon, resulted in a lunar magma ocean (LMO), and initiated the last event of core segregation on Earth. However, the timing and temporal link of these events remain uncertain. Here, we demonstrate that the low thermal conductivity of the lunar crust combined with heat extraction by partial melting of deep cumulates undergoing convection results in an LMO solidification time scale of 150 to 200 million years. Combining this result with a crystallization model of the LMO and with the ages and isotopic compositions of lunar samples indicates that the Moon formed 4.425 ± 0.025 billion years ago. This age is in remarkable agreement with the U-Pb age of Earth, demonstrating that the U-Pb age dates the final segregation of Earth’s core.

https://advances.sciencemag.org/content/6/28/eaba8949
 
NASA MOON NEWS: CLUES EMERGE ABOUT 'EXCITING' NEW ANNOUNCEMENT

Source: The Independent
6 hours ago

Nasa has provoked excitement across the world with the promise that it will reveal a “new discovery about the Moon” in a major announcement.

The space agency gave no details on what the announcement might be, apart from indicating that it “contributes to NASA’s efforts to learn about the Moon in support of deep space exploration” and had been made with Sofia, a converted Boeing 747 that works as a flying observatory.

But clues have begun to emerge about what the announcement could be about to reveal.

As part of the announcement of the press conference – which will take place next week – Nasa gave a full list of the participants. It will include four different people from across the space agency.

Three of them – Paul Hertz, Jacob Bleacher and Naseem Rangwala – are all senior members of staff at various parts of Nasa’s operations that appear to have been involved in the research. Together they represent Nasa’s astrophysics division and its Human Exploration and Operations Mission Directorate, both based at Nasa’s headquarters, and the Sofia mission that helped with the discovery.

But the other person on the list is perhaps the most telling. The briefing will also include Casey Honniball, a postdoctoral fellow at NASA’s Goddard Space Flight Center, Greenbelt, Maryland.

As the blog Nasa Watch points out, Dr Honniball has conducted extensive research into how we might go about finding water on the Moon.

Her PhD dissertation, which is available online and is titled ‘Infrared Remote Sensing Of Volatile Components On The Moon’, includes a report that she and her team had “developed a new approach to detect the actual water molecule on the Moon”, with the technique relying on infrared astronomy.

It goes on to make clear that the method had been put to the test using Sofia, or the Stratospheric Observatory For Infrared Astronomy, which would be needed because such observations are only possible from an “airborne infrared observatory”.

“Using data from SOFIA we report the first direct detection of the water molecule on the illuminated lunar surface," she writes at the end of the abstract.

In August, Dr Honniball was also the lead author on a paper titled ‘Telescopic Observations of Lunar Hydration: Variations and Abundance’ and published in the Journal of Geophysical Research: Planets. As the title suggests, that paper explored in the detail the possibilities of water on the Moon, and how it might behave.

As such, the list of names in the briefing would seem to suggest that the announcement has something to do with the detection of water on the Moon. While there has been evidence that there may be water there before, it is still not definitive, and researchers know relatively little about how that water might behave or where it could be found.

As Nasa’s announcement indicated, the discovery of water on the Moon would be of keen interest as the space agency prepares to head back there, and to use a potential lunar base as a way of travelling deeper into the solar system, such as to Mars.

[...]

https://www.independent.co.uk/life-...t-water-hydration-lunar-surface-b1221638.html
 
You man the moon isnt made out of green cheese but something proceesed?

(So meaning its not worth mining??)
 
You man the moon isnt made out of green cheese but something proceesed?

(So meaning its not worth mining??)
Helium Cheese apparently. It’ll run the CheeseDrives in future Starships. Piloted by Kirk. Cheese. It’s the future.
 
So it wasn't a monolith after all...
Water on the Moon could sustain a lunar base
By Victoria Gill
Science correspondent, BBC News

Published19 minutes ago

Having dropped tantalising hints days ago about an "exciting new discovery about the Moon", the US space agency has revealed conclusive evidence of water on our only natural satellite.
This "unambiguous detection of molecular water" will boost Nasa's hopes of establishing a lunar base.
The aim is to sustain that base by tapping into the Moon's natural resources.
The findings have been published as two papers in the journal Nature Astronomy.
etc

https://www.bbc.co.uk/news/science-environment-54666328
 
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