Decoding the 4.5 billion year old mystery: The time Jupiter was born is revealed

DNVN - Scientists have just announced a groundbreaking discovery, solving a decades-long mystery about the birth of Jupiter - the giant planet in the Solar System.

New research reveals that Jupiter's birth triggered high-speed collisions that created molten droplets preserved in meteorites, tiny time capsules from the earliest days of the solar system. Source: Shutterstock

About 4.5 billion years ago, Jupiter rapidly expanded into the giant planet we see today. Its immense gravity disturbed the orbits of countless rocky and icy bodies—primitive asteroids and comets. These disturbances led to collisions so violent that the rock and dust inside the asteroids melted, creating droplets of molten rock called chondrules. Remarkably, many ancient chondrules have been preserved inside meteorites that have fallen to Earth.

In a new step, scientists from Nagoya University (Japan) and the Italian National Institute for Astrophysics (INAF) have decoded how these chondrules form and used them to pinpoint the exact time Jupiter appeared.

Research published in Scientific Reports shows that chondrule characteristics – including their size and the rate at which they cool in space – are determined by the amount of water contained in the colliding planetesimals. This finding not only matches observations from meteorite samples, but also demonstrates that the birth of giant planets directly drives chondrule formation.

Rounded chondrules are visible on a thin section of the Allende meteorite under a microscope. Credit: Akira Miyake, Kyoto University.

“Time capsule” from 4.6 billion years ago

Chondrules—tiny spheres measuring just 0.1-2 mm across—were once fused together in asteroids as the Solar System formed. Billions of years later, fragments from asteroids have fallen to Earth, bringing with them evidence of the universe’s history. But why chondrules are perfectly round has puzzled scientists for decades.

“When asteroids collide, water immediately evaporates into expanding steam. This phenomenon is similar to the micro-explosions that break molten silicate rock into tiny droplets that we see in meteorites today,” explained study co-author Professor Sin-iti Sirono of Nagoya University’s Department of Earth and Environmental Sciences.

“Previous theories could not explain the properties of chondrules without assuming extremely special conditions, while this model is based on natural conditions that existed in the early Solar System when Jupiter was born,” he added.

Jupiter's gravity causes collisions between small planets that melt rock into water droplets that disperse as water vapor expands. Credit: Diego Turrini and Sin-iti Sirono.

Based on computer simulations, the team shows that Jupiter's enormous gravity triggered high-speed collisions between rocky and water-rich planetesimals, thereby producing massive chondrules.

“We compared the characteristics and numbers of the simulated chondrules with the actual meteorite data and found a striking match,” said Dr. Diego Turrini, co-lead author and senior researcher at INAF. “The model also shows that chondrule production occurred in parallel with the period when Jupiter accumulated nebula gas to reach its enormous size. As the meteorite data show, chondrule formation peaked around 1.8 million years after the birth of the Solar System, which is exactly when Jupiter was born.”

Rounded chondrules are visible on a thin section of the Allende meteorite under a microscope. Credit: Akira Miyake, Kyoto University.

Suggestions for determining the age of planets

According to scientists, this research provides a clearer picture of the formation of the Solar System. However, the production of chondrules by Jupiter is short-lived, unable to explain the diversity of ages of chondrules found in different meteorites.

The most plausible hypothesis is that other giant planets—particularly Saturn—also had similar effects, contributing to the production of more chondrules.

By studying chondrules of different ages, scientists hope to determine the order in which planets in our solar system were formed. The results will not only help understand the history of Earth and its cosmic neighbors, but also open up opportunities to learn how other planetary systems around distant stars formed and evolved.

La Khe (According to SciTech Daily)

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