NASA: Superflares From Young Sun Served as Catalyst for the Development of Life on Earth
It has been widely accepted that the earliest signs of life may have surfaced on Earth four billion years ago, but during this time the sun is only about 70 percent as bright as its today. If that was the case, it would mean that the Earth should have been an iceball, instead of a warm globe with water. This dilemma is called the Faint Young Sun Paradox.
A new study was conducted by NASA to shed some light in the paradox. According to their study published in the journal Nature Geosciences, the young sun might have been more violent 4 billion years ago, producing solar eruptions 10 rimes a day at most.
These superflares repeatedly bombarded the Earth's atmosphere, which is 90 percent molecular nitrogen during that time. The bombardment of penetrated the atmosphere creating chain reactions separating the double-nitrogen molecules to into single nitrogen atom. These single nitrogen atoms in turn split atmospheric carbon dioxide molecule into carbon monoxide and atomic oxygen.
According to the report from Space.com, the free-floating nitrogen and oxygen molecules produced during the chemical reaction started by the sun's superflares may have come together to form nitrous oxide, a greenhouse gas that is 300 times more potent than carbon dioxide. This process could also create hydrogen cyanide, an essential compound necessary for life.
For the study, researchers at NASA put together several stars in the galaxy that is similar with the sun. They arranged it by age creating a functional timeline to show the evolution of the sun. NASA's Kepler Mission captured stars that are similar to the sun about a million years after birth. Closer observation of data from Kepler reveals that these stars produced superflares, a rare super explosion that can be experience today once every century, as many as ten per day.
"We want to gather all this information together, how close a planet is to the star, how energetic the star is, how strong the planet's magnetosphere is in order to help search for habitable planets around stars near our own and throughout the galaxy," said William Danchi, principal investigator of the project at Goddard and a co-author on the paper, in a statement.