Study turns back clock on origins of life on Earth
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
Not Again: More US AID, Missiles Shipped to al Qaeda, al Nusra and ISIS in Syria, Iraq
Two weeks ago, 21WIRE reported on how ISIS and other terrorists militants operating in Syria and Iraq are receiving regular weapons and ‘supply drops’ – forming a ‘rat line’ which seems to be playing a crucial role in keeping this highly profitable conflict going on both sides.
This week, it’s been reported that Jabhat Al-Nusra fighters have been brandishing US-supplied ...
Swedish parliament removes Baroque artist's bare breasted painting for offending feminists and Muslims
A nude painting named Juno, which was painted by baroque artist G E Schröder and has hung in the dining room of the Swedish Parliament for 30 years has been taken down for fear of offending the sensitivities of feminists and Muslim visitors, Swedish newspaper, The Local reported on Thursday.
Explaining the ban on the baroque breasts, a source from the ...
White US children will be minorities by 2020 after immigrant 'baby boom', Census reveals
This is the result of an ongoing trend of declining birth among white Americans and a baby boom among immigrant groups, as well as a surge in immigration.
By the year 2020, 50.2percent of all children in the US are expected to be non-white, according to the Census. By 2044, whites will be outnumbered by minorities.
The Census study, released ...
New Jersey Shopkeeper Hangs 'White History Month' Sign In Window
A deli owner in Flemington, New Jersey, has angered many of his neighbors by posting a sign on his window that reads, "Celebrate Your White Heritage in March White History Month."
Jim Boggess, who is the owner of Jimbo's Deli, says he put up the sign to remind everyone that they should be proud of their race and culture.
"No matter what ...
The Viking ”Maine Penny” Mystery
In 1957, during his second year of digging at the Goddard site; a large prehistoric Indian trade village in Penobscot Bay on the central Maine coast, local resident and amateur archaeologist Guy Mellgren found a small silver coin. The coin is later identified by experts as a Norse silver penny dating to the reign of Olaf Kyrre, king of Norway ...
|More News » |