Old planets grow too hot or cold for life

• Autores: Alice Klein
• Localización: New scientist, ISSN 0262-4079, Nº. 3084, 2016, pág. 12
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The search for life on other worlds has focused on planets in what's known as the habitable zone--the ring around stars where it's the right temperature for liquid water. That has led some to target planets orbiting red dwarf stars, as their smaller size and cooler temperatures mean planets in the habitable zone are closer in, and so easier to spot. But scientists should also look for planets whose stars are the right age, regardless of their size, say Shintaro Kadoya and Eiichi Tajika at the University of Tokyo, Japan. Because stars grow brighter with age, planets at the inner edge of the habitable zone enter a "runaway greenhouse mode", in which their oceans boil away. Meanwhile, planets at the outer edge lose heat-trapping gases from their atmospheres as volcanic activity decreases, so they enter an ice-covered "snowball state".