According to research, only 1% of worlds that may be habitable are 'pale blue dots' like Earth. It is estimated that only 1% of the worlds around stars have planets like Earth, with at least 30 percent of their surface covered with land and located within the so-called habitable zones.
The search for a planet that has similar conditions as our planet is a top priority for astronomers. Not only would this increase the likelihood of us not being alone in the galaxy (universe), but it would also give hope for humankind to one day reach that planet and so make sure that the human species endures the test of time. Our planet will not be here forever. This is a fact. Scientists believe that the current phase of the Sun’s life cycle could end within 5 billion years, even though the full death of the Sun is trillions of years away. By that time, our Solar System’s massive star will have consumed most of its hydrogen core. As a result, the Sun as we know it will no longer exist.
This will result in the Sun becoming a red giant. Nuclear fusion will cease to produce heat. Around this time, NASA predicts the core will become unstable and contract. As the core of the Sun becomes unstable, its outer layers expand. Venus and Mercury will eventually be swallowed by that expansion. The Earth’s magnetic field will also be stripped away by rough solar winds from the Sun. Life as we know it is no longer possible. Of course, this is still a very long, long time away, and chances are other external factors will pose a danger to our existence.
In search of another pale blue dot
“Look again at that dot. That’s here. That’s home. That’s us. On it, everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.” This was a quote by Carl Sagan making reference to the photograph of our planet taken by the Voyager 1 spacecraft on 14 February 1990, about 6.4 billion kilometers (4 billion miles) away.
But how common are such “pale blue dots” where life flourishes and is home to millions of species? According to research, only 1% of worlds that may be habitable are ‘pale blue dots’ like Earth. It is estimated that only 1% of the worlds around stars have planets like Earth, with at least 30 percent of their surface covered with land and located within the so-called habitable zones. A habitable zone is a region surrounding the sun where liquid water can exist. It found only about 20% of potentially habitable worlds have purely oceanic environments, and 80% have land-dominated ecosystems. By modeling the interactions between water in the mantle of a planet and the continents‘ recycling via plate tectonics, the researchers came to this conclusion.
Researchers found that the land-to-sea ratio on Earth (1:3) is finely balanced, but this ratio tends to tip over on most planets and become mostly land or mostly sea. In the Archean, our planet reached these conditions about 2.5 billion years ago, and it is in this delicate balance that we live today. Earth’s fine balance, however, is unstable over billions of years, even though the changes are small. This tipping point could have been reached by other planets much sooner.