The cosmic neighbor that is far too dangerous to visit

Space · Published 25 October 2026 Swipe more like this →

In short: Proxima Centauri is our closest stellar neighbor, sitting just 4.24 light-years away. In astronomical terms, it is practically next door. Yet, despite its proximity, the planet Proxima b may be a desolate wasteland, stripped of its atmosphere by the violent radiation of its host star.

Earth is situated about 24.9 trillion miles (40 trillion kilometers) away from Proxima Centauri. While this distance is vast, it is considered a 'stone's throw' in the context of the universe. The system features Proxima b, an Earth-sized exoplanet that completes an orbit around its host star every 11 days. Because Proxima Centauri is a dim red dwarf, this tight orbit places the planet within the habitable zone, where liquid water could theoretically exist on the surface.

However, the planet's proximity to a red dwarf presents a lethal challenge. Red dwarfs are notoriously active, particularly during their youth, emitting intense stellar radiation and charged particles. High-energy UV light can strike atmospheric molecules, knocking electrons off to create ions. If these electrons possess enough energy, they escape the planet's gravity, pulling oppositely charged particles with them and effectively stripping the atmosphere away into space. Research suggests that for Proxima b, these atmospheric loss rates are so high that habitability is considered implausible.

This phenomenon has significant implications for our understanding of the galaxy. Around three-quarters of the Milky Way's stars are red dwarfs. If most planets orbiting these stars lose their atmospheres to radiation, the majority of the galaxy's rocky planets may be uninhabitable. While some planets might survive using thick atmospheres to absorb radiation or magnetic fields to funnel charged particles away, the intense activity of red dwarfs remains a primary hurdle for finding life beyond our solar system.

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