🌍 What if wandering planets had caused mass extinctions on Earth?

What if Earth's great extinctions were not only due to asteroids or volcanoes, but also to the passage of wandering planets? A recent study suggests that flybys of Pluto-sized objects could have triggered giant tsunamis and volcanic eruptions, disrupting the climate and wiping out a significant portion of life on Earth.

The Chicxulub impact, 66 million years ago, is famous for hastening the end of the dinosaurs' reign. Yet other, far larger extinctions, such as the Permian-Triassic one 251 million years ago, remain unexplained. No crater or iridium anomaly is associated with them. Scientists have long sought a mechanism capable of explaining them.


According to Daniele Fargion, a researcher at the University of Rome and the Capodimonte Observatory, these catastrophes could have a common origin: the close passage of planetary-mass objects from the outer Solar System. These flybys would generate immense gravitational tides, deforming Earth's crust and triggering gigantic volcanic eruptions, planetary tsunamis, and long-lasting climate disruptions.

Evidence of such passages exists in the Earth-Moon system. Fossil corals show that the number of days in a year rapidly decreased at the end of the Devonian. This indicates that the Moon moved away from Earth faster than usual, a phenomenon that a collision could not explain. A massive flyby could have gravitationally pulled the Moon, altering its orbit.

The frequency of these events remains difficult to estimate. Fargion uses Jupiter as a laboratory: its slight tilt and unexplained internal heat could result from 16 collisions with objects half the mass of Earth.

For Earth, even without a collision, flybys would be sufficient to cause several major extinctions. This might explain the Fermi paradox: civilizations could be wiped out by this kind of cosmic cataclysm. The main threat is not the impact itself, but the giant waves that sweep across continents for years.

There exists a reservoir of large bodies, with multiple dwarf planets, at the edge of the Solar System. If one of them were to plunge toward the inner planets, following a perturbation of its orbit, this type of cataclysm could occur. Humanity would then have to take refuge on high ground, far from the oceans, to hope to survive.

Far from being mere speculation, this hypothesis opens a new avenue for understanding the great biodiversity crises. It reminds us that Earth is not isolated: the ballet of dwarf planets can, from time to time, decide the fate of life.

Gravitational tides

Tides are not merely an oceanic phenomenon exclusively linked to the Moon. Any massive object approaching a planet exerts a tidal force, i.e., a difference in attraction between the near side and the far side. The more massive and closer the object, the stronger the effect.

If a dwarf planet the size of Pluto were to graze Earth, the tide would be so powerful that it would raise waves several hundred meters high, deform Earth's crust, and generate internal heat, causing massive volcanic eruptions. These effects could last for years, durably disrupting the climate.

This mechanism helps explain how a single event can cause both tsunamis, eruptions, and climate changes, without leaving an impact crater.