Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




IRON AND ICE
New NASA Research Shows Giant Asteroids Battered Early Earth
by Staff Writers
Moffet Field CA (NASA) Aug 01, 2014


Researchers estimate accretion during the late bombardment contributed less than one percent of Earth's present-day mass, but the giant asteroid impacts still had a profound effect on the geological evolution of early Earth. Prior to four billion years ago Earth was resurfaced over and over by voluminous impact-generated melt.

New research shows that more than four billion years ago the surface of Earth was heavily reprocessed - or melted, mixed, and buried - as a result of giant asteroid impacts. A new terrestrial bombardment model, calibrated using existing lunar and terrestrial data, sheds light on the role asteroid collisions played in the evolution of the uppermost layers of the early Earth during the geologic eon called the "Hadean" (approximately 4 to 4.5 billion years ago).

An international team of researchers from academic and government institutions, including NASA's Solar System Exploration Research Virtual Institute (SSERVI) at NASA's Ames Research Center in Moffett Field, California, published their findings in a paper, "Widespread Mixing and Burial of Earth's Hadean Crust by Asteroid Impacts" in the July 31, 2014 issue of Nature.

"A large asteroid impact could have buried a substantial amount of Earth's crust with impact-generated melt," said Yvonne Pendleton, SSERVI Director at Ames. "This new model helps explain how repeated asteroid impacts may have buried Earth's earliest and oldest rocks."

Terrestrial planet formation models indicate Earth went through a sequence of major growth phases: initially accretion of planetesimals - planetary embryos - over many tens of millions of years, then a giant impact by a large proto-planet that led to the formation of our moon, followed by the late bombardment when giant asteroids several tens to hundreds of miles in size periodically hit ancient Earth, dwarfing the one that killed the dinosaurs (estimated to be six miles in size) only 65 million years ago.

Researchers estimate accretion during the late bombardment contributed less than one percent of Earth's present-day mass, but the giant asteroid impacts still had a profound effect on the geological evolution of early Earth. Prior to four billion years ago Earth was resurfaced over and over by voluminous impact-generated melt.

Furthermore, large collisions as late as about four billion years ago may have repeatedly boiled away existing oceans into steamy atmospheres. Despite the heavy bombardment, the findings are compatible with the claim of liquid water on Earth's surface as early as about 4.3 billion years ago based on geochemical data.

The new research reveals that asteroidal collisions not only severely altered the geology of the Hadean eon Earth, but likely also played a major role in the subsequent evolution of life on Earth as well.

"Prior to approximately four billion years ago, no large region of Earth's surface could have survived untouched by impacts and their effects," said Simone Marchi, SSERVI senior researcher at the Southwest Research Institute in Boulder, Colorado, and the paper's lead author.

"The new picture of the Hadean Earth emerging from this work has important implications for its habitability."

Large impacts had particularly severe effects on existing ecosystems. Researchers found that on average, Hadean Earth more than four billion years ago could have been hit by one to four impactors that were more than 600 miles wide and capable of global sterilization, and by three to seven impactors more than 300 miles wide and capable of global ocean vaporization.

"During that time, the lag between major collisions was long enough to allow intervals of more clement conditions, at least on a local scale," said Marchi.

"Any life emerging during the Hadean eon likely needed to be resistant to high temperatures, and could have survived such a violent period in Earth's history by thriving in niches deep underground or in the ocean's crust."

The research was an international effort led by Marchi and William Bottke from the Southwest Research Institute in Boulder; Linda Elkins-Tanton from Carnegie Institution for Science in Washington; Michael Bierhaus and Kai Wunnemann from the Museum fur Naturkunde in Berlin, Germany; Alessandro Morbidelli from Observatoire de la Cote d'Azur in Nice, France, and David Kring from the Universities Space Research Association and Lunar and Planetary Institute in Houston.

The research was supported in part by SSERVI, a virtual institute that, with international partnerships, brings science and exploration researchers together in a collaborative virtual setting. SSERVI is funded by the Science Mission Directorate and Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington.

.


Related Links
SSERVI
Asteroid and Comet Mission News, Science and Technology






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





IRON AND ICE
Space Systems/Loral conducting technology studies for NASA
Palo Alto, Calif. (UPI) Jul 18, 2013
Space Systems/Loral reports it has been chosen by NASA to study system concepts and technologies for the NASA Asteroid Redirect Mission. The value of the contract, of which SSL is one of a number of companies receiving it, was not disclosed. The Asteroid Redirect Mission to bring small asteroids near Earth into a lunar orbit for analysis by manned and unmanned aircraft. The infor ... read more


IRON AND ICE
Tidal forces gave moon its shape

Riddle of bulging Moon solved at last

China's biggest moon challenge: returning to earth

Lunar Pits Could Shelter Astronauts, Reveal Details of How 'Man in the Moon' Formed

IRON AND ICE
Los Alamos Laser Selected for 2020 Mars Mission

NASA Announces Mars 2020 Rover Payload to Explore the Red Planet as Never Before

Mars 2020 rover will carry tools to make oxygen

NASA Long-Lived Mars Opportunity Rover Passes 25 Miles of Driving

IRON AND ICE
Perlan partners with Airbus to fly glider to edge of space

First synthetic biological leaf could allow humans to colonize space

NASA's IBEX and Voyager spacecraft drive advances in outer heliosphere research

Orion Tests Set Stage for Mission

IRON AND ICE
China's Circumlunar Spacecraft Unmasked

China to launch HD observation satellite this year

Lunar rock collisions behind Yutu damage

China's Fast Track To Circumlunar Mission

IRON AND ICE
Europe's Fifth and Final Resupply Ship Launches to Station

Science and Spacesuit Work While ATV-5 Preps for Launch

Russian Cargo Craft Launches for 6-Hour Trek to ISS

ISS Crew Opens Cargo Ship Hatch, Preps for CubeSat Deployment

IRON AND ICE
US Launches Two Surveillance Satellites From Cape Canaveral

United Launch Alliance Marks 85th Successful Launch

US aerospace firm outlines New Zealand-based space program

China to launch satellite for Venezuela

IRON AND ICE
Young binary star system may form planets with weird and wild orbits

Hubble Finds Three Surprisingly Dry Exoplanets

Astronomers come up dry in search for water on exoplanets

Hubble Finds Three Surprisingly Dry Exoplanets

IRON AND ICE
New characteristics of complex oxide surfaces revealed

Building the Foundation for Future Synthetic Biology Applications with BRICS

Collecting just the right data

New Approach to Form Non-Equilibrium Structures




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.