| Business Standard | - |
A
new synthesis by researchers offers a coherent picture of how
metabolism, and thus all life, emerged on Earth. Describing how living
organisms emerged from Earth's abiotic chemistry has remained a
conundrum for scientists.
'Microbe led to mass extinction 251m years ago'
LONDON: A humble microbe, instead of a devastating meteorite or a
catastrophic volcanic eruption, wiped off over 90% of the species on
Earth 251-million-years ago, scientists believe. According to prevailing
theory, the mass extinction at the end of the Permian period was
triggered by volcanic eruptions over a vast area of what is now Siberia, which led to a dramatic rise in greenhouse gas emissions.
However, according to Daniel Rothman of MIT, the scenario just doesn't fit the facts.
From his analysis of an end-Permian sediment sample from China, Rothman says carbon levels surged much too quickly for geological processes to be at work. Microbes can generate carbon compounds that fast.
As his group analysed the genome of Methanosarcina - a methanogen responsible for most of biogenic methane - they found that it gained this ability 231m years ago. Methanosarcina needs large amounts of nickel to produce methane quickly. The team discovered that nickel levels spiked 251m years ago in the sediment samples. This suggests Methanosarcina did trigger the extinction
However, according to Daniel Rothman of MIT, the scenario just doesn't fit the facts.
From his analysis of an end-Permian sediment sample from China, Rothman says carbon levels surged much too quickly for geological processes to be at work. Microbes can generate carbon compounds that fast.
As his group analysed the genome of Methanosarcina - a methanogen responsible for most of biogenic methane - they found that it gained this ability 231m years ago. Methanosarcina needs large amounts of nickel to produce methane quickly. The team discovered that nickel levels spiked 251m years ago in the sediment samples. This suggests Methanosarcina did trigger the extinction
Close call signals Earth needs an asteroid shield
LONDON: Extensive monitoring systems and an Armageddon-style protocol
is needed to save the Earth from a potentially hazardous asteroid,
expected to fly by our planet in 2029, experts say. Actor Bruce Willis
and his co-stars are given just 18 days to destroy a vast asteroid
which threatens to wipe out life on Earth in the Hollywood movie
"Armageddon" .
Scientists say the world must come up with a similar emergency plan after an asteroid whistled within a whisker of the Earth on Tuesday, only two days after it was first detected by astronomers , 'The Telegraph' reported. The Apophis asteroid , first detected in 2004, will come within 36,000 kilometres of Earth when it passes by and it can be seen with the naked eye as a burning point in the sky.
Scientists said although there is no chance of the asteroid colliding with Earth, there is an extremely small chance it could fall into a gravitational loop and come back to hit the planet in 2038.
The asteroid which passed by this week, known as 2012 XE54 measured just 36 metre across, but the last known asteroid of such a size to hit Earth wiped out an area of Russian forest the size of London in 1908.
Scientists are becoming increasingly concerned about the possible impact of asteroids measuring less than 1km across, which are not typically picked up by surveying programmes and could only be detected at very short notice.
Delegates from across the world will gather at the UN in February to come up with a framework for earlier detection of asteroids, and a plan of action if a collision is deemed possible.
Scientists say the world must come up with a similar emergency plan after an asteroid whistled within a whisker of the Earth on Tuesday, only two days after it was first detected by astronomers , 'The Telegraph' reported. The Apophis asteroid , first detected in 2004, will come within 36,000 kilometres of Earth when it passes by and it can be seen with the naked eye as a burning point in the sky.
Scientists said although there is no chance of the asteroid colliding with Earth, there is an extremely small chance it could fall into a gravitational loop and come back to hit the planet in 2038.
The asteroid which passed by this week, known as 2012 XE54 measured just 36 metre across, but the last known asteroid of such a size to hit Earth wiped out an area of Russian forest the size of London in 1908.
Scientists are becoming increasingly concerned about the possible impact of asteroids measuring less than 1km across, which are not typically picked up by surveying programmes and could only be detected at very short notice.
Delegates from across the world will gather at the UN in February to come up with a framework for earlier detection of asteroids, and a plan of action if a collision is deemed possible.
Subscribe to:
Comments (Atom)