planetesimals tagged posts

Earth and Mars: Built from different cosmic recipes

Image of Mars
“You might have expected that two planets formed side by side in the same solar system would share a more similar formation history,” says Professor Anders Johansen, who co-led a new study about the origin of Earth and Mars. Photo: Canva

Four and a half billion years ago, Earth and Mars were born in the rotating cloud of gas and dust that would eventually become our solar system. Yet exactly how the planets formed remains one of the most disputed questions in planetary science.

Now, researchers at the University of Copenhagen are adding new evidence to the debate. Using a novel approach, they have reconstructed the earliest stages of the planets’ formation by analyzing their chemical composition.

And the results surprised them.

“The most surprising result was that Earth and Ma...

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Supernova immersion model suggests Earth-like planets are more common in the universe

New supernova theory suggests Earth-like planets are more common in the Universe
Schematic picture of the system assumed in this study. Credit: Science Advances (2025). DOI: 10.1126/sciadv.adx7892

Rocky planets like our Earth may be far more common than previously thought, according to new research published in the journal Science Advances. It suggests that when our solar system formed, a nearby supernova (the massive explosion of a star near the end of its life) bathed it in cosmic rays containing the radioactive ingredients to make rocky, dry worlds. This mechanism could be ubiquitous across the galaxy.

Earth-like planets are thought to form from planetesimals (objects made of rock and ice) that were dried out early in the solar system’s history...

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Super-Earths and mini-Neptunes: More Earth-like planets may exist

illustration of planets

A new study presents a compelling new model for the formation of super-Earths and mini-Neptunes – planets that are 1 to 4 times the size of Earth and among the most common in our galaxy. Using advanced simulations, the researchers propose that these planets emerge from distinct rings of planetesimals, providing fresh insight into planetary evolution beyond our solar system.

A new study by Rice University researchers Sho Shibata and Andre Izidoro presents a compelling new model for the formation of super-Earths and mini-Neptunes — planets that are 1 to 4 times the size of Earth and among the most common in our galaxy...

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To Stick or to Bounce: Size determines the Stickiness of Cosmic Dust Aggregates

Micrometer-scale dust particles from protoplanetary disks, or sites around stars with particles and hydrogen and/or other gasses, aggregate to form planetesimals, or kilometer-scale building blocks of planets. Planetesimals, in turn, merge due to mutual gravity. ©JAMSTEC

Microparticle dust aggregates, which are thought to play a role in the formation of new planets, are less likely to stick together after a collision when the aggregates are larger.

Current evidence suggests that microparticles of cosmic dust collide and stick together to form larger dust aggregates that may eventually combine and develop into planets...

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