14 DAY TRIAL // The thing that immediately stands out about Earth when seeing it from orbit is that fact that three quarters of its surface is covered in water. Experts have been trying to determine how such vast accumulations of water developed on a rocky planet, and a new study proposes an interesting explanation.
The mystery is made even more, well, mysterious by the fact that other Earth-like planets in the solar system, such as Venus and Mars, appear to have had oceans on their surfaces in the past as well.
But this doesn't really make sense when looking at how planets of this type form. As they coalesce from the protoplanetary disk of a young star, they become balls of molten lava, which then solidify to form a harsh, rocky body, with a heavy metal core.
Planetary scientists have always been puzzled at how water fits into this picture. There are theories that state water was brought as ice aboard comets traveling from the Oort Cloud to the inner solar system.
But is this really the case? Experts at the Massachusetts Institute of Technology (MIT) don't seem to think so. In a new study, they show that this couldn't possibly be true for Earth, Mars, Venus, and a host of exoplanets orbiting inside their parent stars' habitable zones.
The research group says that rocky clumps called planetesimals – planets in their first stage of development – contained trace amounts of water themselves, enough to plant the seeds of their future oceans.
According to planetary scientist Lindy Elkins-Tanton, planetesimals contained volumes of water equal to at least .01 to .001 percent of their total mass.
The expert, who is the Mitsui Career Development assistant professor of geology at the MIT Department of Earth, Atmospheric and Planetary Sciences, says that the bodies which formed Earth and similar rocky planets were hundreds and thousands of kilometers in diameter.
The expert concedes however that the sizes of planetesimals is still a matter of debate. Details of the new investigation were published in the November issue of the esteemed journal Astrophysics and Space Science.
What Elkins-Tanton is basically proposing is that the tiny amounts of water contained with these structures were sufficiently large to produce Steam in the atmosphere.
Later on, as the newly-formed planet cooler, the steam condensed into liquid oceans. “These little bits of water get processed into planets in ways we can predict,” the expert explains.
“The study gives us a very important starting point for understanding the evolution and history of planets,” explains NASA Jet Propulsion Laboratory (JPL) planetary atmosphere expert Pin Chen.
He believes the new work is “well-grounded in fundamental principles of physics, chemistry and thermal dynamics.” As such, it could conceivably be used to look for liquid oceans on the surface of Earth-like exoplanets.