Subscribe free to our newsletters via your
. Moon News .




MOON DAILY
Dating the moon-forming impact event with meteorites
by Staff Writers
Tucson AZ (SPX) Apr 22, 2015


One possible realization of the Moon-forming impact event is animated. Here it is assumed that a Mars-sized protoplanet, defined as having 13 percent of an Earth-mass, struck the proto-Earth at a 45-degree angle near the mutual escape velocity of both worlds. The "red" particles, comprising 0.3 percent of an Earth-mass, were found to escape the Earth-Moon system. Some of this debris may eventually go on to strike other solar system bodies like large main belt asteroids. "Yellow-green" particles go into the disk that makes the Moon. "Blue" particles were accreted by the proto-Earth. The details of this simulation can be found in Canup, R. (2004, Simulations of a late lunar-forming impact, Icarus 168, 433-456). Image courtesy Robin Canup, Southwest Research Institute. Watch an animation on the research here.

Through a combination of data analysis and numerical modeling work, researchers have found a record of the ancient Moon-forming giant impact observable in stony meteorites. Their work will appear in the April 2015 issue of the Journal Science.

The work was done by NASA Solar System Exploration Research Virtual Institute (SSERVI) researchers led by Principal Investigator Bill Bottke of the Institute for the Science of Exploration Targets (ISET) team at the Southwest Research Institute and included Tim Swindle, director of the University of Arizona's Lunar and Planetary Laboratory.

The inner Solar System's biggest known collision was the Moon-forming giant impact between a large protoplanet and the proto-Earth. The timing of this giant impact, however, is uncertain, with the ages of the most ancient lunar samples returned by the Apollo astronauts still being debated.

Numerical simulations of the giant impact indicate this event not only created a disk of debris near Earth that formed the Moon, but it also ejected huge amounts of debris completely out of the Earth-Moon system.

The fate of this material, comprising as much as several percent of an Earth mass, has not been closely examined until recently. However, it is likely some of it blasted main belt asteroids, with a record plausibly left behind in their near-surface rocks. Collisions on these asteroids in more recent times delivered these shocked remnants to Earth, which scientists have now used to date the age of the Moon.

The research indicates numerous kilometer-sized fragments from the giant impact struck main belt asteroids at much higher velocities than typical main belt collisions, heating the surface and leaving behind a permanent record of the impact event.

Evidence that the giant impact produced a large number of kilometer-sized fragments can be inferred from laboratory and numerical impact experiments, the ancient lunar impact record itself, and the numbers and sizes of fragments produced by major main belt asteroid collisions.

Once the team concluded that pieces of the Moon-forming impact hit main belt asteroids and left a record of shock heating events in some meteorites, they set out to deduce both the timing and the relative magnitude of the bombardment.

By modeling the evolution of giant impact debris over time and fitting the results to ancient impact heat signatures in stony meteorites, the team was able to infer the Moon formed about 4.47 billion years ago, in agreement with many previous estimates. The most ancient Solar System materials found in meteorites are about one hundred million years older than this age.

Insights into the last stages of planet formation in the inner solar system can be gleaned from these impact signatures. For example, the team is exploring how they can be used to place new constraints on how many asteroid-like bodies still existed in the inner Solar System in the aftermath of planet formation.

They can also help researchers deduce the earliest bombardment history of ancient bodies like Vesta, one of the targets of NASA's Dawn mission and a main belt asteroid whose fragments were delivered to Earth in the form of meteorites.

It is even possible that tiny remnants of the Moon-forming impactor or proto-Earth might still be found within meteorites that show signs of shock heating by giant impact debris. This would allow scientists to explore for the first time the unknown primordial nature of our homeworld.

Co-author Swindle, who specializes in finding the times when meteorites or lunar samples were involved in large collisions, said: "Bill Bottke had the idea of looking at the asteroid belt to see what effect a Moon-forming giant impact would have, and realized that you would expect a lot of collisions in the period shortly after that.

"Here at LPL, we had been determining ages of impact events that affected meteorites, and when we got together, we found that our data matched his predictions," he added. "It's a great example of taking advantage of groups that work in two different specialties - orbital dynamics and chronology - and combining their expertise."

Intriguingly, some debris may have also returned to hit the Earth and Moon after remaining in solar orbit over timescales ranging from tens of thousands of years to 400 million years.

"The importance of giant impact ejecta returning to strike the Moon could also play an intriguing role in the earliest phase of lunar bombardment," said Bottke, who is an alumnus of the University of Arizona's Lunar and Planetary Laboratory. "This research is helping to refine our time scales for 'what happened when' on other worlds in the Solar System."

Yvonne Pendleton, Director of the NASA SSERVI Institute, notes: "This is an excellent example of the power of multidisciplinary science. By linking studies of the Moon, of main belt asteroids, and of meteorites that fall to Earth, we gain a better understanding of the earliest history of our Solar System."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
University of Arizona
Mars News and Information at MarsDaily.com
Lunar Dreams and more






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





MOON DAILY
Japan planning moon mission: space agency
Tokyo (AFP) April 20, 2015
Japan plans to launch an unmanned mission to the moon as a stepping stone to a future visit to Mars, officials and local media said Monday. The Japan Aerospace Exploration Agency (JAXA) unveiled the plan for a moon lander to a council of the cabinet office and the ministry of education, culture, sports science and technology, a JAXA official said. If successful, Japan will be the fourth ... read more


MOON DAILY
Robotic Arm Gets Busy on Rock Outcrop

Mars might have liquid water

NASA's Curiosity Rover Making Tracks and Observations

NASA Mars Rover's Weather Data Bolster Case for Brine

MOON DAILY
Violent methane storms on Titan may solve dune direction mystery

NASA-funded Study Explains Saturn's Epic Tantrums

Explaining Saturn's Great White Spots

Saturn Spacecraft Returns to the Realm of Icy Moons

MOON DAILY
Capstone: 2015

NASA's New Horizons Nears Historic Encounter with Pluto

Pluto, now blurry, will become clear with NASA flyby

NASA Extends Campaign for Public to Name Features on Pluto

MOON DAILY
Yutu finds Moon still active in old age

Japan planning moon mission: space agency

Manned Moon Flight Planned For 2030

A new view of the moon's formation

MOON DAILY
Chemists create tiny gold nanoparticles that reflect nature's patterns

Optics, nanotechnology combined to create low-cost sensor for gases

Water makes wires even more nano

Light-powered gyroscope is world's smallest

MOON DAILY
First Super-Heavy Angara launch to take place in 2021

Brazil Abandons Joint Satellite Launch System Project With Ukraine

US Space Company Unveils New Rocket

Boeing-Lockheed team for Vulcan rocket with reusable engine

MOON DAILY
Chinese scientists mull power station in space

China completes second test on new carrier rocket's power system

China's Yutu rover reveals Moon's "complex" geological history

China's Space Laboratory Still Cloaked

MOON DAILY
Sixth SpaceX Delivery of Station Research With a Side of Caffeine

Research for One-Year Space Station Mission Launched On Falcon 9

Astronaut Hadfield to release first space album

Special 3-D delivery from space to Marshall Space Flight Center




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.