Are There Any Earth-like Planets in the Universe?
It is given that humans have been in the long search for answers whether there are other earth-like planets in the universe. This question has been asked for centuries and many people who have been asking are always looking for more information for a very long time. People should know that for life to exist outside the Earth, it is necessary that the right conditions should apply first and choosing the right planet is the start of this.
For people who are still into this question, scientists found out that there are 4 exoplanets that has the potential to be habitable. This means that aside from earth, there are also other earth-like planets where humans can survive. Exoplanets are those planets orbiting another particular star other than the sun. For a planet to be habitable, the right atmospheric gases and temperature should be present in the planet.
An estimated 4 exoplanets have been discovered.
1. Gliese 581 d, which is a warm superterran type of planet having a surface temperature of -40°F or 233°K. It can orbit for 67 days.
2. Kepler-22 b is another warm superterran planet with a surface temperature of 315°K or -107°F and has an orbit period of 290 days.
3. HD 88521 b is also a warm superterran having 351°K or 172°F as its surface temperature and 88 days of orbit period.
4. Gliese 667C c has the same planet type as of the 3 exoplanets and has 84°F or 302°K in its surface temperature and orbits its star for 28 days.
The Terrain and Characteristics of Exoplanets
All of these planets have a dense atmosphere along with liquid water. These planets are warm superterran or rocky planets that are larger than the size of the earth.
When ESI or Earth Similarity Index is done, planets that are almost earth-like are identified as its size, composition, atmosphere and temperature are checked. With a rate of 0.0 as no similarity with that of the earth to 1.0 being identical to earth, those that are included in the rate of 0.8 are considered as almost identical to earth. For the 4 exoplanets that have been discovered, only Gliese 667C c has gone beyond the 0.8 rate and is considered as the planet nearer to the composition of the earth.
For the distance from earth, Kepler-22 b has the farthest distance from Earth that would take 619 light years to reach. While Gliese 581 d has the nearest distance among the 4 exoplanets having 20.2 light years away from Earth. Though these planets are considered to let life survive, it would take humans about thousands of millennia for covering a single light year.
If any spacecraft would send humans faster than the speed of Voyager 1 of 39,000 mph, travelling from Earth to Gliese 581 d, Gliese 667C c and HD 85512 b would take less than 1,000,000 years while travelling to Kepler-22 b would take 10, 651,133 years.
Other than the 4 exoplanets discovered, there are still billions of galaxies that can be found in the universe. Within the galaxy of earth, it is estimated that about 160 billion unnamed or undiscovered exoplanets are hosted by over 100 billion stars. Among these unknown exoplanets lies another question whether there are among these are earth-like planets and if there are other existing life forms in each of it.