Physics Cosmic Scale

If Mars was orbiting our neighbor star, its entire atmosphere would be gone in just 10 million years—poof.

arXiv · March 13, 2026 · 2603.11561

David A. Brain, Ofer Cohen, Thomas E. Cravens, Kevin France, Alex Glocer, Parker Hinton, Francois Leblanc, Yingjuan Ma, Akifumi Nakayama, Shotaro Sakai, Ryoya Sakata, Kanako Seki, Julián D. Alvarado-Gómez, Zachory Berta-Thompson, Eryn M. Cangi, Michael Chaffin, Jean-Yves Chaufray, Renata Frelikh, Yoshifumi Futaana, Katherine Garcia-Sage, Lukas Hanson, Mats Holmström, Bruce Jakosky, Riku Jarvinen, Ravi Kopparapu, Daniel R. Marsh, Aimee Merkel, Thomas Earle Moore, Yuta Notsu, Rachel A. Osten, William K. Peterson, Laura Peticolas, Robin Ramstad, Kevin B. Stevenson, Robert Strangeway, Wenyi Sun, Naoki Terada, Aline A. Vidotto

Why it matters

Red dwarfs are the most common stars in the galaxy, but they are surprisingly hostile. By simulating a 'Mars-like' planet around a nearby old star, scientists proved that the stellar wind is so aggressive it would strip away a breathable atmosphere thousands of times faster than happens in our solar system.

From the abstract

Atmospheric escape is an important process that influences the evolution of planetary atmospheres. A variety of physical mechanisms can contribute to escape from an atmosphere, including thermal escape, ion escape, photochemical escape, and sputtering. Here we estimate escape rates via each of these processes for a hypothetical Mars-like exoplanet orbiting Barnard's star (an old, inactive M dwarf star). We place the planet at an orbital distance that receives the same total stellar flux as it do