The question of whether habitable planets like Earth are rare or abundant in the universe is still a topic of scientific debate and ongoing research. However, I can provide some insights based on our current understanding.
The universe is vast, containing billions of galaxies, each with billions of stars. With such an enormous number of stars, it is plausible to assume that there are a significant number of planets in the universe. Furthermore, recent astronomical observations and discoveries suggest that planets are common around stars. Many exoplanets, which are planets outside our solar system, have been detected, including rocky planets within the habitable zone of their respective stars.
The habitable zone, also known as the "Goldilocks zone," refers to the region around a star where conditions could potentially support liquid water on the surface of a planet. Water is a crucial ingredient for life as we know it, so the presence of liquid water is often considered a key factor in determining the potential habitability of a planet.
While we have found numerous exoplanets and identified potentially habitable candidates, it is challenging to determine their true habitability and the presence of life. Many factors contribute to a planet's habitability, such as its distance from its star, atmospheric composition, presence of a protective magnetic field, and the existence of other necessary conditions.
Given the vast number of stars and the increasing discovery of exoplanets within habitable zones, it is plausible to believe that habitable planets like Earth could be relatively common in the universe. However, further research and observations are needed to provide a more definitive answer.