Until today, the most widely accepted explanation for the origins of our planet and its satellite was that h4.5 billion years ago a gigantic object collided with Earthand, from the detached fragments, the Moon was born. And that the impact caused such heat that all the hydrogen evaporated and was lost in space, leaving both the Earth and its satellite dry. Later, the water returned to Earth in meteorites and to the Moon in comets.
Now, new research reveals thatthe origin of the water found from the rocks brought by the Apollo missions is the same as that of the terrestrial water. And given this evidence, the simplest explanation is that “hydrogen was already on Earth at the time of the great impactand that there was no significant loss during the formation of the Moon, “Alberto Saal, a scientist at Brown University (USA) and author of an article published today by the magazine, told SINC.Science.
To reach this conclusion, the researchersanalyzed the proportion of deuterium – an isotope of hydrogen – in the sample. Water molecules formed near the Sun generally have less deuterium than those formed at the outer edges of the solar system. According to the researchers, the proportion of this isotope in lunar water is the same as in 98% of the terrestrial one. In addition, both coincide with that of the carbonaceous chondrites, primitive meteorites formed near Jupiter “that were the common origin of the volatile components of the Earth and the Moon, and probably of the entire inner solar system,” according to Saal.
The analyzed hydrogen is trapped in volcanic crystals and, thanks to this, it was not lost in lunar eruptions and researchers have been able to get an idea of what the interior of the Moon looks like.
It was in 2011 when another investigation by the same team observed that these samples had as much enclosed water as lavas from the bottom of the Earth’s ocean. “So, the implications were that the interior of both celestial bodies harbored reserves with equivalent amounts of hydrogen,” explains the scientist.
“The main point of our new article is thatthe Moon’s hydrogen did not originate from comets as previously thought, but from primitive meteorites like the ones that brought it to Earth”Says Saal. These results are not necessarily incompatible with the idea that the Moon was formed from the large impact of an asteroid early in Earth’s life, but they raise the question of how it is possible that water survived such a collision. “We need to go back to the beginning and discover more about what causes the big impacts” concludes the researcher.
