Ancient droplets found in meteorites reveal the history of planet formation.

About 4.5 billion years ago, Jupiter expanded quickly into the giant planet we see today. Its immense gravity disturbed the paths of countless rocky and icy objects, known as planetesimals, which resembled present-day asteroids and comets.

These disturbances led to violent collisions so energetic that the rock and dust inside the planetesimals melted, producing droplets of molten rock called chondrules. Many of these ancient droplets are still preserved within meteorites that fall to Earth.

In a new breakthrough, scientists from Nagoya University in Japan and the Italian National Institute for Astrophysics (INAF) have uncovered how these chondrules were created and used them to precisely date Jupiter’s formation.

Their research, published in Scientific Reports, reveals that the traits of chondrules, including their size and cooling rates in space, were shaped by the amount of water present in the colliding planetesimals. This discovery not only matches what scientists observe in meteorite samples but also confirms that the birth of planets directly drove the creation of chondrules.