Exploring Planetary Habitability

Habitability hinges on liquid water, appropriate temperature ranges, and a stable environment. Planets must orbit within the habitable zone where water can exist as a liquid.

An atmosphere with the right chemical composition is crucial. Gases like oxygen, ozone, and methane can hint at biological activity. The presence of a thick atmosphere also protects life from radiation.

A planetary magnetic field shields surface life from stellar winds and cosmic radiation. It also prevents atmosphere stripping, which Mars experienced due to its weak magnetosphere.

Biosignatures are indicators of life, such as specific atmospheric gases or pigments. For instance, Earth's red edge phenomenon is a unique biosignature caused by plant chlorophyll absorption.

Scientists use stellar flux, planet density, and escape velocity as proxies to evaluate exoplanet habitability. These factors can suggest a planet's ability to retain an atmosphere and liquid water.

Tardigrades can survive in space! These microscopic creatures endure extreme conditions, including intense radiation and the vacuum of space, challenging our understanding of habitability.