Study turns back clock on origins of life on Earth
2009 05 25
By Julie Steenhuysen | Reuters.com
The bombardment of Earth by asteroids 3.9 billion years ago may have enhanced early life, according to a new University of Colorado study. Credit: NASA/JPL
A heavy bombardment by asteroids the size of Ireland was not enough to wipe out life on Earth 3.9 billion years ago, researchers said on Wednesday in a finding that turns back the clock of life by 500 million years.
Many scientists had thought the violent pelting by massive asteroids during the period known as the Late Heavy Bombardment would have melted the Earth's crust and vaporized any life on the planet.
But new three-dimensional computer models developed by a team at the University of Colorado at Boulder shows much of Earth's crust, and the microbes living on it, could have survived and may even have thrived.
"These new results push back the possible beginnings of life on Earth to well before the bombardment period 3.9 billion years ago," said Oleg Abramov, a researcher at the university whose study appears in the journal Nature.
"It opens up the possibility that life emerged as far back as 4.4 billion years ago, about the time the first oceans are thought to have formed," Abramov said in a statement.
To study this period, Abramov and colleague Stephen Mojzsis used data from moon rocks, meteorite samples and the dented surfaces of neighboring planets to develop a three-dimensional model of this period of bombardment.
"What we did was recreate the Late Heavy Bombardment on a computer," Abramov said, adding that the simulation randomly "smacked the Earth" with giant asteroids.
The team then looked at the impact that would have had on the Earth's temperature in the so-called geophysical habitable zone -- a zone representing the top 2.5 miles of the Earth's crust.
Based on these models, Abramov said this sustained period of impacts would have killed any life on the Earth's surface, but not all life on Earth, as many had assumed.
"We find it is essentially impossible to sterilize the entire habitable zone of the Earth by this kind of bombardment," Abramov said in a telephone interview.
"Certainly, the surface of the Earth was sterilized repeatedly," he said.
But he said hydrothermal vents below the surface of the Earth may have offered sanctuaries for certain heat-loving microbes, and may have even provided a kind of incubator for life.
He said many scientists had thought that a cataclysmic bombardment event would have sterilized the planet and life would have had to start anew.
"The important thing about these results is they push back the possible beginnings of life as we know it," he said.
"Exactly when life originated on Earth is a hotly debated topic," said Michael New, an astrobiologist at the National Aeronautics and Space Administration, which sponsored the research.
"These findings are significant because they indicated life could have begun well before the Late Heavy Bombardment, during the so-called Hadean Eon of Earth's history 3.8 billion to 4.5 billion years ago," New said in a statement.
(Editing by Michael Conlon and Doina Chiacu)
Article from: www.Reuters.com
Dinosaur Killer May Have Been Volcanism, Not Asteroid
New Insight into Earth's Early Bombardment
Holes in the Earth: 170 and Counting
Greatest Mysteries: How Did Life Arise on Earth?
The Asteroid Paradox: Harm or Help? [Video]
Latest News from our Front Page
6,000-Year-Old Temple with Possible Sacrificial Altars Discovered
2014 10 21
A 6,000-year-old temple holding humanlike figurines and sacrificed animal remains has been discovered within a massive prehistoric settlement in Ukraine.
Built before writing was invented, the temple is about 60 by 20 meters (197 by 66 feet) in size. It was a "two-story building made of wood and clay surrounded by a galleried courtyard," the upper floor divided into five ...
What happened to Journalist Serena Shim? Assassinated? Find out what happened to Serena, Press TV director calls on Turkey
2014 10 21
Press TV news director Hamid Reza Emadi says the “suspicious death,” of the news channel’s correspondent in Turkey is a tragedy for “anyone who wants to get the truth.”
Emadi made the remarks in an interview with Press TV on Sunday following Serena Shim’s death across the border from Syria’s Kurdish city of Kobani, where the ISIL terrorists and Kurdish fighters ...
Ancient Roman Nanotechnology Inspires Next-Generation Holograms for Information Storage
2014 10 21
The Lycurgus Cup, as it is known due to its depiction of a scene involving King Lycurgus of Thrace, is a 1,600-year-old jade green Roman chalice that changes colour depending on the direction of the light upon it. It baffled scientists ever since the glass chalice was acquired by the British Museum in the 1950s, as they could not work ...
Rapid Geomagnetic Reversal Possibility: Confirmed
2014 10 21
From the video: "The scientists who conducted the study are still unsure why the magnetic field is weakening, but one likely reason is the Earth’s magnetic poles are getting ready to flip, said Rune Floberghagen, the ESA’s Swarm mission manager. In fact, the data suggest magnetic north is moving toward Siberia."
Tune into Red Ice Radio:
Ben Davidson - Suspicious0bservers: Space Weather ...
Georgia Guide Stone 2014 cube stone removal
2014 10 21
From: Youtube: Was it all just a gag? it seems the cube stone just happens to be made out of the same Elberton granite that the rest of this morbid monument is made from.
|More News » |