How the Solar System Got Its ‘Great Divide’ and Why It Matters

Scientists, including those from CU Boulder, have finally scaled the solar system’s equivalent of the Rocky Mountain range.   (Image: via   pixabay  /  CC0 1.0)
Scientists, including those from CU Boulder, have finally scaled the solar system’s equivalent of the Rocky Mountain range. (Image: via pixabay / CC0 1.0)

Scientists, including those from CU Boulder, have finally scaled the solar system’s equivalent of the Rocky Mountain range. In a study recently published in Nature Astronomy, researchers from the United States and Japan unveil the possible origins of our cosmic neighborhood’s “Great Divide.” This well-known schism may have separated the solar system just after the Sun first formed.

The phenomenon is a bit like how the Rocky Mountains divide North America into east and west. On the one side are “terrestrial” planets like Earth and Mars. They are made up of fundamentally different types of materials than the more distant “Jovians,” such as Jupiter and Saturn. lead author Ramon Brasser, a researcher at the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology in Japan, said:

Brasser and coauthor Stephen Mojzsis, a professor in CU Boulder’s Department of Geological Sciences, think they have the answer, and it may just shed new light on how life originated on Earth.

A Sun disk holds vital clues

The duo suggests that the early solar system was partitioned into at least two regions by a ring-like structure that formed a disk around the young Sun. This disk might have held major implications for the evolution of planets and asteroids, and even the history of life on Earth. Mojzsis said:

Mojzsis noted that the Great Divide, a term that he and Brasser coined, does not look like much today. It is a relatively empty stretch of space that sits near Jupiter, just beyond what astronomers call the asteroid belt.

But you can still detect its presence throughout the solar system. Move sunward from that line, and most planets and asteroids tend to carry relatively low abundances of organic molecules.

Go the other direction toward Jupiter and beyond, however, and a different picture emerges: Almost everything in this distant part of the solar system is made up of materials that are rich in carbon. Mojzsis said this dichotomy:

Go the other direction toward Jupiter and beyond, however, and a different picture emerges: Almost everything in this distant part of the solar system is made up of materials that are rich in carbon. (Image: via pixabay / CC0 1.0)

Go the other direction toward Jupiter and beyond, however, and a different picture emerges: Almost everything in this distant part of the solar system is made up of materials that are rich in carbon. (Image: via pixabay / CC0 1.0)

Many scientists assumed that Jupiter was the agent responsible for that surprise. The thinking went that the planet is so massive that it may have acted as a gravitational barrier, preventing pebbles and dust from the outer solar system from spiraling toward the Sun. But Mojzsis and Brasser were not convinced. The scientists used a series of computer simulations to explore Jupiter’s role in the evolving solar system.

They found that while Jupiter is big, it was probably never big enough early in its formation to entirely block the flow of rocky material from moving sunward. Brasser said:

A solution in plain sight

For years, scientists operating an observatory in Chile called the Atacama Large Millimeter/submillimeter Array (ALMA) had noticed something unusual around distant stars: Young stellar systems were often surrounded by disks of gas and dust that, in infrared light, look a bit like a tiger’s eye. If a similar ring existed in our own solar system billions of years ago, Brasser and Mojzsis reasoned, it could theoretically be responsible for the Great Divide.

imagespr2016cbnrao16cb25nrao16cb25a_nrao

Two so-called "ALMA disks" as seen in infrared light around distant stars. ((Image: ALMA, ESO/NAOJ/NRAO)

Two so-called ‘ALMA disks’ as seen in infrared light around distant stars. ((Image: ALMA, ESO/NAOJ/NRAO)

 

That’s because such a ring would create alternating bands of high- and low-pressure gas and dust. Those bands, in turn, might pull the solar system’s earliest building blocks into several distinct sinks — one that would have given rise to Jupiter and Saturn, and another Earth and Mars. Mojzsis said:

But, he added, there’s a caveat:

Provided by: Daniel Strain,  [Note: Materials may be edited for content and length.]

Follow us on Twitter or subscribe to our weekly email

NASA Finds Potential Earth-Like Planet 100 Lights Years Away
Chinese Idiom: ‘Where Water Flows, a Channel Will Form’