Tag Archives: moon

50-Mile Landslides Spotted on Saturn’s Icy Moon

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Long landslides spotted on Saturn’s moon, Iapetus, could help provide clues to similar movements of material on Earth. Scientists studying the icy satellite have determined that flash heating could cause falling ice to travel 10 to 15 times farther than previously expected on Iapetus.

Extended landslides can be found on Mars and Earth, but are more likely to be composed of rock than ice. Despite the differences in materials, scientists believe there could be a link between the long-tumbling debris on all three bodies.

“We think there’s more likely a common mechanism for all of this, and we want to be able to explain all of the observations,” lead scientist Kelsi Singer of Washington University told SPACE.com.

Rock-Hard Ice on Saturn’s Moon

Giant landslides stretching as far as 50 miles litter the surface of Iapetus. Singer and her team identified 30 such displacements by studying images taken by NASA’s Cassini spacecraft.

More From Space.com: Photos: Latest Saturn Photos from NASA’s Cassini Orbiter

Composed almost completely of ice, Iapetus already stands out from other moons. While most bodies in the solar system have rocky mantles and metallic cores, with an icy layer on top, scientists think Iapetus is composed almost completely of frozen water. There are bits of rock and carbonaceous material that make half the moon appear darker than the other, but this seems to be only a surface feature.

Ice on Iapetus is different from ice found on Earth. Because the moon’s temperature can get as low as 300 degrees Fahrenheit, the moon’s ice is very hard and very dry.

“It’s more like what we experience on Earth as rock, just because it’s so cold,” Singer said.

Slow-moving ice creates a lot of friction, so when the ice falls from high places, scientists expected that it would behave much like rock on Earth does. Instead, they found that it traveled significantly farther than predicted.

How far a landslide runs is usually related to how far it falls, Singer explained. Most of the time, debris of any type loses energy before traveling twice the distance it fell from. But on Iapetus, the pieces of ice move 20 to 30 times as far as their falling height.

Flash heating could be providing that extra push.

Flash heating occurs when material falls so fast that the heat doesn’t have time to dissipate. Instead, it stays concentrated in small areas, reducing the friction between the sliding objects and allowing them to travel faster and farther than they would under normal conditions.

“They’re almost acting more like a fluid,” Singer said.

On Iapetus, falling material has a good chance of reaching great speeds because there are a number of great heights to fall from. The moon hosts a ring of mountains around its bulging equator that can tower as high as 12 miles, and the longest run-outs discovered are associated with the ridge and with impact-basin walls.

Scientists think that the landslides are relatively recent, and could have been triggered by impacts in the last billion years or so.

“You don’t see a lot of small craters on the landslide material itself,” Singer said, although the surrounding terrain boasts evidence of bombardment. Over time, landscapes tend to be dotted by falling rocks, so the less cratered a surface is, the younger it is thought to be.

More From Space.com: Photos of Saturn’s Moons

Resting on the ridges and walls, the material gradually becomes more unstable. Close impacts could set them off, but powerful, distant impacts reverberating through the ice could also send them tumbling.

The research was published in the July 29 issue of the journal Nature Geoscience.

Connecting Ice and Rock

Differences in gravity, atmosphere and water content make landslides seen on Iapetus difficult to duplicate in the laboratory. But the fact that they happen on different types of worlds makes it more likely that the mechanism triggering the extended slide is dependent on things unique to either environment.

“We have them on Iapetus, Earth and Mars,” Singer said. “Theoretically, they should be very similar.”

Singer pointed out the implications for friction within fault lines, which produces earthquakes. As plates on Earth move, the rocks within a fault snag on each other, until forces drag them apart.

But sometimes, the faults slip farther than scientists can explain based on their understanding of friction. If flash heating occurs within the faults, it could explain why the two opposing faces slide the way they do, and provoke a better understanding of earthquakes.

In such cases, flash heating would cause minerals to melt and reform, producing an unexpected material around the faults. Some such materials have been identified at the base of long landslides on Earth.

“If something else is going on, like flash heating, or something making [the material] have a lower coefficient of friction, this would affect any models that use the coefficient of friction,” Singer said.

Image courtesy of NASA/JPL/Space Science Institute

This article originally published at Space.com
here

Read more: http://mashable.com/2012/07/30/saturn-moon-landslide/

Juno Spacecraft Passes By Earth And Moon

Juno Spacecraft Passes By Earth And Moon

The space age may be in its infancy, but it’s still here. 

NASA‘s Juno spacecraft is traveling to Jupiter, and is set to reach the gassy planet by July of 2016. The craft is outfitted with a slew of special equipment to track, test, and observe space. 

One sensor is a special camera “optimized to track faint stars” which recently had a very unique view of the Earth and our moon.

From 600,000 miles away, Juno captured one frame at a time and sent the footage back to Earth to be processed into this very special video. 

Already, the clip has amassed over half a million views!

 

Read more: http://www.viralviralvideos.com/2013/12/12/juno-spacecraft-passes-by-earth-and-moon/

Rebooted NASA Spacecraft Begins a New Mission 36 Years After Launch

Isee-3-moon

Artist’s concept image of ISEE-3 (ICE) spacecraft.
Image: NASA

A 36-year-old NASA spacecraft began a new interplanetary science mission on Sunday when it made a close pass by the moon.

The privately controlled International Sun-Earth Explorer 3 spacecraft, also called ISEE-3, flew by the moon at approximately 2:16 p.m. EDT.

The ISEE-3 spacecraft is under the control of the ISEE-3 Reboot Project, a private team of engineers who took control of the probe earlier this year under an agreement with NASA. The team initially hoped to move the NASA probe into a stable orbit near the Earth. But attempts failed when the team discovered that the spacecraft, which NASA launched in 1978, was out of the nitrogen pressurant needed to get the job done.

Now, ISEE-3 Reboot Project engineers are focusing their efforts on an interplanetary science mission, since at least some of the probe’s 13 instruments are still working. By using a network of individual radio dishes across the world, the team will listen to the ISEE-3 spacecraft for most of its orbit around the sun.

Officials announced this week that they would collaborate with Google to offer live spacecraft data at the site SpacecraftForAll.com. Financial terms were not disclosed. Chris Lintott, of the BBC’s “The Sky at Night,” moderated a Google Hangout on ISEE-3.

“The main feature of this is a new website developed by Google Creative Lab in collaboration with the ISEE-3 Reboot Project team that features a history of the ISEE-3 mission as well as a presentation of data currently being received from ISEE-3,” co-founder Keith Cowing said in a statement.

The spacecraft was originally launched in 1978 to study the sun, and was retasked for other science missions such as looking at comets. NASA put ISEE-3 into hibernation in 1998, where it remained until the private group reactivated it this year under a Space Act Agreement.

Members raised about $160,000 through crowdfunding, most of which is gone due to the need to rent dish time at NASA’s Deep Space Network to listen in, and to fly team members to the Arecibo Observatory in Puerto Rico for communications.

To learn more about the ISEE-3 Reboot Project, visit: http://spacecollege.org/.

This article originally published at Space.com
here

Read more: http://mashable.com/2014/08/11/isee-3-buzzes-moon/

LADEE’s Mission to the Moon

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) will perform a relatively short mission to the moon in order to study conditions near the lunar surface and its atmosphere. This information will help scientists understand other bodies in the solar system like asteroids and moons of the most distant planets. 

 

LADEE was launched at 11:27 pm EDT off the coast of Virginia and the event was visible to tens of millions of people. Shortly after launch when LADEE (pronounced like “laddie”) detached from the rocket, there was a minor issue with the reaction wheels being turned off due to a safeguarding program. The program was disabled and LADEE’s reaction wheels came back online and are working properly.

 

After about one month of travel LADEE began its orbit. This was monitored with a skeleton crew as 97% of NASA’s staff was furloughed in the recent shutdown of the United States government. 

LADEE just made space communication history by using lasers to communicate with Earth from its lunar orbit faster than ever before. Pulsed laser beams sent data 239,000 miles (384,633 kilometers) back to Earth’s surface at a rate of 622 megabits per second. For comparison, 4G LTE downloads run about 10-17 megabits per second.

LADEE’s mission is broken up into five phases: pre-launch; launch, ascent & acquisition; commissioning; science operations; and extended mission or end of life. 

During its 100 science day mission, LADEE will inspect the atmosphere and dust environment on the moon from a variety of altitudes. Eventually, it will go as low as 12 miles (19 km) off the surface of the moon to collect information. Following the science phase, if it does not receive an extended mission, LADEE’s altitude will be gradually lowered until it finally comes to rest on the lunar surface, though it will not be targeted to land in any particular place.

 

The spacecraft itself is unique in that it was not custom created like many other spacecraft. It was fashioned from parts that can be created on an assembly line for a variety of different applications, which made it considerably less expensive to manufacture. This approach will allow NASA to create spacecraft that look relatively similar but can be customized based on what is needed for a specific mission. LADEE weighs in at about 844 pounds (383 kilograms) and uses around 295 Watts of power.

 

LADEE has many sophisticated tools. It will use an Ultraviolet and Visible Light Spectrometer (UVS) to ascertain the moon’s atmosphere. The lunar atmosphere is not consistent and has been described as “bumpy.” Neutral Mass Spectrometer (NMS) will record inconsistencies in the atmosphere as the moon travels through different environments and completes several orbits. The Lunar Dust Experiment (LDEX) will analyze particles of dust suspended in the lunar atmosphere. This analysis will help determine whether lunar dust was charged by UV light from the sun and caused a glow on the horizon before sunrise. This question has stumped scientists since the days of the Apollo missions.

Photo Gallery

Read more: http://www.iflscience.com/space/ladee%E2%80%99s-mission-moon

This Stunning Image Of Saturn’s Rings Contains A Surprise

If youre confused by this image, we dont blame you. What youre seeing here are the rings of Saturn and the gas giant itself. But the planets rings are, well, rings. Why do they appear to be criss-crossing each other here?

The answer is a pretty awesome illusion, snapped by the Cassini spacecraft thats currently in orbit around Saturn. The bulk of the image is the rings itself, while in the background is the planet Saturn. The lines going the other direction to the rings are actually the shadow of the rings on the planet, visible because the rings are semi-transparent.

Thats not the only surprising thing about this image, though. Take a look just below the middle, and youll spot a gap in one of the rings with a white dot in it. This gap is known as the Encke gap, and the white dot is the moon Pan (28 kilometers/17 miles across). Moons like this form gaps by cleaning out debris from the rings.

Now you see it… NASA/JPL-Caltech/Space Science Institute

Cassini took this image from a distance of 1.9 million kilometers (1.2 million miles) from Pan on February 11, 2016, with a scale of 10 kilometers (6 miles) per pixel. The spacecraft arrived in orbit around Saturn in 2004, and since then it has provided uswith incredible views and data from Saturn and its various moons, including Enceladus and Titan.

But, sadly, all good things must come to an end. On September 15 next year, the spacecraft will be sent to its death in the atmosphere of Saturn. This is because, as it runs out of fuel, NASA wants to ensure it wont accidentally hit one of the potentially life-harboring moons and contaminate it with material from Earth.

Dont despair too much, though, because this final death plunge will see Cassini return some groundbreaking science to Earth. Itll be sending back data constantly until its final moments, so well get incredible data from within Saturns rings and from its upper atmosphere as well something weve never gotten before.

Until then, bask in the glory of images like these. With no other spacecraft to Saturn currently in the works, we really shouldn’t take Cassini for granted.

Here’s the full image in all its glory.NASA/JPL-Caltech/Space Science Institute

Photo Gallery

Read more: http://www.iflscience.com/space/stunning-image-saturn-contains-more-one-surprise

Does the Moon Have Levitating Lunar Dust?

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Did you hear about the new restaurant on the moon? Great food, but no atmosphere.

While that wisecrack has been floating about in space circles for decades, a NASA lunar orbiter will gather detailed information about the moon’s atmosphere next year, including conditions near its surface and environmental influences on lunar dust.

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) is to depart the Earth for the moon in August 2013. LADEE is loaded with science gear, including instruments that can address a lingering question that’s rooted in space history: Are electrostatically lofted lunar dust particles present within the moon’s tenuous atmosphere?

Twilight Rays on the Moon

In the 1960s, several NASA Surveyor moon landers relayed images showing a twilight glow low over the lunar horizon persisting after the sun had set. Also, a number of Apollo astronauts orbiting the moon saw twilight rays before lunar sunrise or lunar sunset.

In addition, some have floated the theory that the glowing transient lunar phenomenon seen from Earth might stem from sunlight reflecting off of suspended lunar dust.

LADEE will investigate this moon magic trick of levitating lunar dust. The spacecraft has the tools it needs to address mysteries and questions that have been around since Apollo, said Rick Elphic, LADEE project scientist at NASA’s Ames Research Center in Mountain View, Calif.

Ames is responsible for managing the mission, building the spacecraft and performing mission operations.

Elphic told SPACE.com that among its duties, the LADEE mission can further investigate tantalizing hints about the dust and the moon’s exotic atmosphere.

“If we fly LADEE through the regions where the Apollo command module observations were made, we will know right away if there are small grains there or not,” Elphic said. LADEE’s Lunar Dust Experiment (LDEX) is a very sensitive dust-detecting instrument, he said, and scientists may be able to place new upper limits on the dust in the first week of the spacecraft’s orbiting operations.

Nagging Moon Question

“If LADEE never sees levitated dust, that settles the question for the high-altitude observations, at least for its mission time frame,” Elphic said.

Still, there’s the nagging question about what Surveyor saw, the near-surface horizon glow. “That might be something else entirely, and can only be addressed with a surface mission,” Elphic said.

“If LADEE does see dust, we will then have a basis for expecting the same phenomena at all other ‘nearly-airless’ bodies around the solar system,” Elphic added.

This dust may not pose much of a hazard, Elphic added, but the physics will need to be explained. Right now, no one has a good end-to-end model for getting dust to loft and secondly, stay suspended for long periods, he said.

“If LADEE observes levitated dust, then scientists will have to explain it. Right now, no one can,” Elphic said.

One-Way Trip Off the Moon

One scientist ready for the new data to be gleaned by LADEE is Harrison “Jack” Schmitt, Apollo 17 moonwalker and geologist. He and astronaut Eugene Cernan walked the lunar surface in December 1972 — the last mission of the Apollo moon landings.

“I do not know if LADEE will see lunar dust in the lunar atmosphere, but I will not be surprised if there is none,” Schmitt told SPACE.com. “We know about several transient gases in that atmosphere, and these may be what causes the horizon glow at sunrise and sunset.”

Moon dust, Schmitt added, was always been on his mind.

“My concern about levitated dust has always been that levitation, if it occurs at all, probably has to be a one-way trip off the moon … because many flat rock surfaces are essentially free of very fine dust, as I personally witnessed on Apollo 17.”

Schmitt said that if dust has been levitated and then dropped again, he would expect the rock surfaces to be covered with such dust.

“Nonetheless, LADEE data on this question, as well as various gases, should give us a lot to think about,” Schmitt said.

This article originally published at Space.com
here

Read more: http://mashable.com/2012/11/20/nasa-ladee-levitating-lunar-dust/

Exoplanets Explain Why the ‘Dark Side’ of the Moon Has No Face

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A composite image of the Moon.
Image: NASA

Heat radiating from the young Earth could help solve the more than 50-year-old mystery of why the far side of the moon, which faces away from Earth, lacks the dark, vast expanses of volcanic rock that define the face of the Man in the Moon as seen from Earth, researchers say.

The Man in the Moon was born when cosmic impacts struck the near side of the moon, the side that faces Earth. These collisions punched holes in the moon’s crust, which later filled with vast lakes of lava that formed the dark areas known as maria or “seas.”

In 1959, when the Soviet spacecraft Luna 3 transmitted the first images of the “dark” or far side of the moon, the side facing away from Earth, scientists immediately noticed fewer maria there. This mystery — why no Man in the Moon exists on the moon’s far side — is called the Lunar Farside Highlands Problem.

“I remember the first time I saw a globe of the moon as a boy, being struck by how different the far side looks,” study co-author Jason Wright, an astronomer at Pennsylvania State University, said in a statement. “It was all mountains and craters. Where were the maria?”

Far Side of the Moon

The farside of the moon, taken by the Lunar Reconnaissance Orbiter Camera.

Image: NASA/Goddard/Arizona State University

Now scientists may have solved the 55-year-old mystery; heat from the young Earth as the newborn moon was cooling caused the difference. The researchers came up with the solution during their work on exoplanets, which are worlds outside the solar system.

“There are many exoplanets that are really close to their host stars,”lead study author Arpita Roy, also of Penn State, told Space.com. “That really affects the geology of those planets.”

Similarly, the moon and Earth are generally thought to have orbited very close together after they formed. The leading idea explaining the moon’s formation suggests that it arose shortly after the nascent Earth collided with a Mars-size planet about 4.5 billion years ago, with the resulting debris coalescing into the moon. Scientists say the newborn moon and Earth were 10 to 20 times closer to each other than they are now.

“The moon and Earth loomed large in each other’s skies when they formed, ” Roy said in a statement.

Since the moon was so close to Earth, the mutual pull of gravity was strong. The gravitational tidal forces the moon and Earth exerted on each other braked their rotations, resulting in the moon always showing the same face to Earth, a situation known as tidal lock.

The moon and Earth were very hot shortly after the giant impact that formed the moon. The moon, being much smaller than Earth, cooled more quickly. Since the moon and Earth were tidally locked early on, the still-hot Earth — more than 4,530 degrees Fahrenheit (2,500 degrees Celsius) — would have cooked the near side of the moon, keeping it molten. On the other hand, the far side of the moon would have cooled, albeit slowly.

The difference in temperature between the moon’s halves influenced the formation of its crust. The lunar crust possesses high concentrations of aluminum and calcium, elements that are very hard to vaporize.

“When rock vapor starts to cool, the very first elements that snow out are aluminum and calcium,” study co-author Steinn Sigurdsson of Penn State said in a statement.

Aluminum and calcium would have more easily condensed in the atmosphere on the colder far side of the moon. Eventually, these elements combined with silicates in the mantle of the moon to form minerals known as plagioclase feldspars, making the crust of the far side about twice as thick as that of the near side.

“Earthshine, the heat of Earth soon after the giant impact, was a really important factor shaping the moon,” Roy said.

When collisions from asteroids or comets blasted the moon’s surface, they could punch through the near side’s crust to generate maria. In contrast, impacts on the far side’s thicker crust failed to penetrate deeply enough to cause lava to well up, instead leaving the far side of the moon with a surface of valleys, craters and highlands, but almost no maria.

“It’s really cool that our understanding of exoplanets is affecting our understanding of the solar system,” Roy said.

Future research could generate detailed 3D models testing this idea, Roy suggested. The authors detailed their findings June 9 in the Astrophysical Journal Letters.

This article originally published at Space.com
here

Read more: http://mashable.com/2014/06/16/farside-of-the-moon/

China Plans To Land The First Probe On The Far Side Of The Moon By 2018

Earthlings have been sending probes to explore the Moon since 1959.But in those 57 years, the far side of our satellitehas remained untouched by human footsteps and probes alike. Now, China hopes to change that.

According to Chinese state mediaXinhua News Agency, China aims to go to the farside of the Moon by 2018, as reported byReuters. Change-4 an unmanned probe named after a mythological Chinese goddess of the Moon will explore and survey the geology of the uncharted lunar lands.

This side of the Moon, which never faces Earth, has been seen in imagery taken from spacecrafts. The first-everphotographs were taken in 1959, when the Soviet Union deployed their Luna 3 spacecraft.

We havent been to the far side of the Moon yet as crucial communication signals to and from Earth are essentially blocked out.This means thatin order for a probe to be in contact with Earth, a satellite or spacecraft would also have to be launched into lunar orbit so that signals can be relayed.However, it is precisely for that reason that Chinawants to build a basethere, as being sheltered from the constant stream of Earths radio interface could give a radio telescope a clearer view of the universe.

President Xi Jinping has made space exploration a top priority for China,hoping to use the space program as a demonstration of their increasing economic and technological prowess. As of yet, their missions have been accused of merely mimickingprevious missions by the Russians and Americans. However, if Change-4 is a success, China will cement its place as a major new player in the space explorationgame.

Read more: http://www.iflscience.com/space/china-aims-visit-far-side-moon-2018

Jupiter’s Largest Moon Gets Mapped For the First Time

Galileo discovered a point of light near Jupiter in 1610, which he initially thought was a star. A few days later he corrected himself and named the satellite Ganymede, which is not only the largest moon around Jupiter, but the largest in the entire solar system.  Over 400 years later, scientists have finally been able to complete a geologic map of the entire moon. The study was led by Wes Patterson from the Johns Hopkins Applied Physics Laboratory and was published by the U. S. Geological Survey.

Ganymede is the third of the Galilean satellites and takes about a week to revolve around Jupiter. Its diameter is actually larger than the planet Mercury but it has just one quarter of Mercury’s mass. Ganymede also has a special property that no other moon in our solar system has: a magnetosphere. Scientists believe that Ganymede’s core is made of molten iron, just like Earth.

Ganymede has been imaged thoroughly during the Voyager and Galileo missions, images which were integral to making the geological map. This is the fourth map of its kind to be created, which categorize differences of the terrain which formed at different times. Geologic maps exist of two of Jupiter’s other moons, Io and Callisto, as well as Earth’s moon. The information will be used in order to help understand how the moon was formed and how it changed over time due to collisions.

Ganymede’s surface is composed mostly of ice with a mantle of rock surrounding the molten core, but there are incredibly interesting geological features. The darker areas are the oldest regions of the moon. There is a considerable number of craters due to impacts over the course of the solar system’s history. The lighter regions are relatively younger and are thought to have been formed by tectonic activity which was influenced by a dynamic gravitational relationship with Jupiter’s other satellites. The gravitational pull likely caused tectonic friction, which heat up the ice enough to crack it and for water to escape out. Once at the surface the water could freeze over again, essentially making ice scars. 

Scientists have noted that nearly every geological feature discovered on an icy moon can also be found on Ganymede, making this map an incredibly useful tool in understanding how the surface topography formed and evolved.

The full map, which includes several other images and an extensive legend, can be viewed on the website for the U.S. Geological Survey. Image credit: USGS

Read more: http://www.iflscience.com/space/jupiter%E2%80%99s-largest-moon-gets-mapped-first-time

Dating The Moon

 
The moon was born when a Mars-sized body impacted Earth during its very early days. The debris from both objects spewed into space and ultimately coalesced into our moon. Scientists trying to date this moon-forming impact have come up with a wide range of ages: from as early as 30 million years after the birth of the solar system to as late as 100 million years after the Milky Way was formed. 
 
By creating a “geologic clock,” researchers now show that the moon-forming impact must have occurred 95 million years after the start of the solar system, plus or minus 32 million years. 
 
That makes the moon millions and millions of years younger than some previous estimates, which were based on radioactive dating of elements like uranium. When you have an element with a known rate of radioactive decay, you can back-calculate a time for when collected moon rocks were formed. But geochemists disagree about these numbers a lot. 
 
To achieve this revised date, an international team led by Seth Jacobson from Observatoire de la Côte d’Azur in Nice, France, devised a new method based on measurements of the Earth’s interior combined with computer simulations of the protoplanetary disk from which the Earth and other planets formed. 
 
They started by simulating the growth of the “terrestrial planets” Mercury, Venus, Earth, and Mars from the planetary building blocks orbiting the Sun. By analyzing the growth history of those planets from 259 simulations, they discovered a relationship between the time the Earth was impacted and the amount of material added to our planet after that collision.
 
You see, after the big moon-forming impact, proto-Earth was smashed into by other, smaller objects — these caused the Earth to gain some mass later on. So they constrained their model with the concentration of highly “siderophile” elements (elements like platinum and iridium that like to be chemically associated with iron). Previous work has shown that these are proportional to the mass accumulated on Earth post-impact.
 
“When the moon-forming event occurs, this melts the entire surface of the Earth,” Jacobson tells National Geographic. All the iron present near the surface sinks into the Earth’s core, taking iron-loving, siderophile elements along with it. So, any of these metals present on the surface arrived on objects that hit our planet after its core formed.
 
Together, all of these revealed a relationship that works like a “geologic clock” to date the moon-forming event. Basically, when was the last time Earth was completely molten
 
Their calculations show that the moon formed between 63 million and 127 million years after the beginning of the solar system. It seems like wide range, yes, but it rules out an early moon-forming event.
 
Plus, this is the first geologic clock of early solar system history that doesn’t rely on interpretations of the radioactive decay. “We were excited to find a ‘clock’ for the formation time of the Moon that didn’t rely on radiometric dating methods. This correlation just jumped out of the simulations and held in each set of old simulations we looked at,” Jacobson says in a news release
 
The work was published in Nature earlier this week. 
 
 
 

Read more: http://www.iflscience.com/space/dating-moon