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
Kanye West says in his VMA 2015 speech that he's running for president in 2020
'And yes, as you probably could have guessed by this moment, I have decided in 2020 to run for president.'
Kanye West received the Michael Jackson Video Vanguard Award at tonight's MTV Video Music Awards, and he closed his acceptance speech by announcing he's running for president in 2020. Yes, really!
The segment started with a bang when West was handed his ...
White students in Australia rejecting "multicultural" agenda, this is a problem apparently
According to Dr Christina Ho from Sydney’s University of Technology, White Students have not obeyed the command to become “multicultural”.
White Students have very rarely mixed with non-White groups, and Dr Ho thinks that this is a problem which must be solved.
“Schools are becoming more segregated in terms of both class and ethnicity,” she told the Sydney Morning Herald. “More and more ...
Sweden: The De-balling of the Vikings
For some reason, the deliberately-injected moral and mental cancer known as 'liberalism', aka 'progressivism' has always seemed to metastasize faster in the Nordic countries, particularly Scandinavian ones. This phenomenon is also observable among the American descendants of Scandinavian immigrants in places like Minnesota and Wisconsin.
The hypothesis of this reporter is that the innate, perhaps even genetic, altruism and human ...
New Monsanto Spray Kills Bugs by Messing With Their Genes
In a fascinating long piece in MIT Technology Review, Antonio Regalado examines the genetically modified seed industry's latest blockbuster app in development—one that has nothing to do with seeds. Instead, it involves the industry's other bread-and-butter product: pesticide sprays. But we're not talking about the poisonous chemicals you convinced your dad to stop dousing the lawn with. The novel sprays ...
Obama to speak with Jewish groups on Iran deal
President Barack Obama is using a Friday webcast to try to allay concerns from Jewish communities about the nuclear agreement with Iran.
Obama will deliver remarks about the agreement and take questions from participants. The webcast is being organized by two major Jewish organizations that have held similar events with Israeli Prime Minister Benjamin Netanyahu and Energy Secretary Ernest Moniz.
The Israeli ...
|More News » |