According to a team of investigators, one of the reasons why our planet is suffering from a shortage of water is that Earth formed in a different area of the solar system than first thought, a region that was significantly drier than current planetary formation models hold.
Though one could easily point out that more than three quarters of the planet is covered in water, experts say that the chemical actually makes up less than 1 percent of our world's total mass.
Additionally, most of this water was probably brought here aboard asteroids and comets, during the Late Heavy Bombardment (LHB), between 4.3 and 3.8 billion years ago. The issue therefore remains - why was not the planet formed with more water?
The most important element here, experts say, is the solar system's snow line, an area beyond which icy compounds can condense. It could be that this line was not at its current location more than 4.5 billion years ago, when Earth began forming.
What the new study suggests is that this line was actually a lot farther away from the Sun back then than current models would suggest. This is very important, since the world is believed to have been formed from water-rich substances beyond the snow line.
“Unlike the standard accretion-disk model, the snow line in our analysis never migrates inside Earth's orbit. Instead, it remains farther from the sun than the orbit of Earth, which explains why our Earth is a dry planet,” Mario Livio explains, Space
“In fact, our model predicts that the other innermost planets – Mercury, Venus and Mars – are also relatively dry,” adds the expert, a coauthor of the new study, and a research scientist at the Baltimore, Maryland-based Space Telescope Science Institute (STScI).
According to measurements, the solar system's snow line currently lies in the Inner Asteroid Belt, between the orbits of Mars and Jupiter. STScI experts believe that the line was never closer to the Sun, as current wisdom suggests.
“If the snow line was inside Earth's orbit when our planet formed, then it should have been an icy body. Planets such as Uranus and Neptune that formed beyond the snow line are composed of tens of percents of water. But Earth doesn't have much water, and that has always been a puzzle,” adds Rebecca Martin.
The expert is also based at the STScI. She is a coauthor of the new paper detailing the findings, which was recently accepted for publication in an upcoming issue of the esteemed scientific journal Monthly Notices of the Royal Astronomical Society.