You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "what's the closest habitable planet to earth?" whose answer is Proxima Centauri.
Each document should contain about 30 words, and these documents should contain useful information.

Query: closest habitable planet to Earth
Useful Output:

Doc 1: Proxima b is the closest known, potentially habitable planet. Nonetheless, the discovery of a planet potentially favourable to life in our
Doc 2: Astronomers have confirmed the existence of Proxima b, an Earth-sized exoplanet orbiting the closest star to our Sun — Proxima Centauri,
Doc 3: It is the closest exoplanet to us in the universe. Given the fact that Proxima b is within the habitable zone of its star, meaning liquid water
Doc 4: The average distance from Earth to Proxima Centauri is about 4.24 light-years (40 trillion kilometers). The ion drive propels the spacecraft at
Doc 5: Proxima Centauri b is located within the classical habitable zone of its star and receives about 65% of Earth's irradiation.