Home / Topics / Particle Physics & Cosmology
Habitable zone
Beginner
Orbit range allowing liquid water.
The orbital region where liquid water could exist on a planet's surface; depends on the star's luminosity. Not a guarantee of life.
For the Sun about 0.95–1.4 AU.
Atmosphere and magnetic field also matter.
In more detail
The habitable zone is the range of distances from a star where liquid water could exist on a planet's surface. It depends on the star's luminosity and the planet's properties.
Real-world uses
- Astronomers prioritise habitable zone planets for follow-up observations.
- It guides searches for life beyond Earth.
- Astrobiologists look for exoplanets in the habitable zone, where the temperature may allow liquid water on the surface.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Does a planet in the habitable zone have life?
Not necessarily. Many other factors affect habitability.
Does the zone change with star type?
Yes. Hotter, brighter stars have wider and more distant habitable zones.
Does the habitable zone guarantee life?
No. It is only a necessary condition: a planet also needs the right atmosphere, chemistry and stability to support life.
Related topics in Particle Physics & Cosmology
Critical density · Fate of the universe · Exoplanets · Astronomical distances · Parallax and standard candles · Multiverse ideas