'Great Divide': Ring-like structure split our solar system in two, sowed seeds for life on Earth, study shows

The 'Great Divide' is a ring-like structure—made of dust and gas—that existed billions of years ago, when the Sun had just been created, according to the new study


                            'Great Divide': Ring-like structure split our solar system in two, sowed seeds for life on Earth, study shows
(K. Ebert/Innovative Ideas & Method)

We may finally understand why the inner system occupied by rocky planets such as Earth and Mars is so different from the outer solar system inhabited by gas giants such as Jupiter and Saturn.

These differences can be explained by a ring-like structure—made of dust and gas—called the "Great Divide" that existed billions of years ago, when the Sun had just been created, suggests a new study. This partition may also explain how life evolved on the Earth, say the authors of the study.

"The work arose, thanks to the realization that the inner and outer solar system have a different composition," co-author Stephen Mojzsis, a professor in CU Boulder's Department of Geological Science tells MEA WorldWide (MEAWW).

But these differences in composition goes against a theory that traces the birth of planets. According to the theory, billions of years ago, materials in the outer solar system must have moved inwards, towards the Sun. These materials, in turn, must have come together to give rise to planets. If the theory is true, planets all over the solar system should be carved out of the same materials.

This, however, was not the case. Materials such as carbon, volatiles, or ices and gases dominate gas giants -- but exist in small numbers along with the inner solar system, puzzling scientists. So Mojzsis and his team began a hunt to figure out what kept the outer solar system materials from populating the inner solar system.

The team started out by eliminating the suspicion on Jupiter: Scientists believed that Jupiter's massive size hindered materials and dust in the outer solar system from moving towards the sun. However, Mojzsis's analysis revealed that the planet was not big enough in its early days to entirely block this flow.

The ALMA ring around distant stars. (Credits: ALMA, ESO/NAOJ/NRAO)

So the team looked for an alternative explanation. Staring at distant worlds offered clues, thanks to the observatory -- Atacama Large Millimeter/ submillimeter Array (ALMA). The team realized that young stars from distant worlds are often surrounded by disks of gas and dust. Mojzsis wondered if a similar ring existed in our own solar system, billions of years ago.

These rings may have acted as a gatekeeper, say the authors. The rings create alternating bands of high- and low-pressure gas and dust. This led the team to suspect that one of those bands may have had a hand in blocking the passage of materials into the inner solar system.

Still, carbon managed to find its way into the Earth. This, according to the team, indicates that the ring was far from perfect: it let materials to pass through the divide, sowing the seeds for life on Earth. "Those materials that might go to the Earth would be those volatile, carbon-rich materials," Mojzsis says. "And that gives you water. It gives you organics."

The study has been published in Nature Astronomy.

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