Scientists have long been on a hunt to unravel the mysteries of how life began on Earth. Now, a new study suggests life on the planet may have been seeded by a young sun that bombarded superflares.
In a new study published in the journal Nature Geoscience on May 23, researchers used models of the chemistry of the early Earth's atmosphere and data from observations made by NASA's Kepler space telescope of other stars that resemble the Solar System's sun in the first few hundred million years of life.
Their findings suggest that very powerful and frequent coronal ejections from a violent young sun could have warmed infant Earth, which helped make the conditions suitable to support life about 4 billion years ago.
Scientists have long been puzzled as to how the first organisms evolved on Earth 4 billion years ago when the planet should have been much colder than it is today since the sun at the time was only about 70 percent as bright as it currently is. Experts call this the Faint Young Sun Paradox.
Study author Vladimir Airapetian, from NASA's Goddard Space Flight Center in Greenbelt, Maryland, said that given the sun's brightness during this period, the Earth should have been an icy ball. Geological evidence, however, shows that the planet was warm with liquid water.
It turned out based on the study's findings that while the young sun was fainter, it was likely more tempestuous frequently blasting out superflares that would have smashed molecular nitrogen in the atmosphere.
"Nitrogen fixation in the early terrestrial atmosphere can be explained by frequent and powerful coronal mass ejection events from the young Sun-so-called superflares," the researchers wrote in their study.
The process produced nitrous oxide, the laughing gas, whose greenhouse effect is 300 times more powerful than carbon dioxide, and hydrogen cyanide that produce amino acids known to be the building blocks of protein needed for life.
"As the particles from the space weather traveled down the magnetic field lines, they would have slammed into abundant nitrogen molecules in the atmosphere," said Airapetian.
"Changing the atmosphere's chemistry turns out to have made all the difference for life on Earth."