Washington: The Moon contains clues to the ancient mysteries of the Sun, which are crucial to understanding the development of life, according to NASA scientists, including one of Indian origin. Around four billion years ago, the Sun went through violent outbursts of intense radiation, spewing scorching, high-energy clouds and particles across the solar system.
These growing pains helped seed life on early Earth by igniting chemical reactions that kept Earth warm and wet, said researchers at NASA's Goddard Space Flight Center in the US. These solar tantrums also may have prevented life from emerging on other worlds by stripping them of atmospheres and zapping nourishing chemicals, they said.
Just how destructive these primordial outbursts were to other worlds would have depended on how quickly the early Sun rotated on its axis. The faster the Sun turned, the quicker it would have destroyed conditions for habitability.
This critical piece of the Sun's history has bedeviled scientists, said Prabal Saxena, an astrophysicist at NASA's Goddard Space Flight Center. "We didn't know what the Sun looked like in its first billion years, and it's super important because it likely changed how Venus' atmosphere evolved and how quickly it lost water," said Saxena.
"It also probably changed how quickly Mars lost its atmosphere, and it changed the atmospheric chemistry of Earth," he said. Saxena wondered why there is significantly less sodium and potassium in lunar regolith, or Moon soil, than in Earth soil, when the Moon and Earth are made of largely the same stuff.
This question, revealed through analyses of Apollo-era Moon samples and lunar meteorites found on Earth, has puzzled scientists for decades -- and it has challenged the leading theory of how the Moon formed. Our natural satellite took shape, the theory goes, when a Mars-sized object smashed into Earth about 4.5 billion years ago. The force of this crash sent materials spewing into orbit, where they coalesced into the Moon.
"The Earth and Moon would have formed with similar materials, so the question is, why was the Moon depleted in these elements?" said Rosemary Killen, a planetary scientist at NASA. The two scientists suspected that one big question informed the other -- that the history of the Sun is buried in the Moon's crust.