Earth Analog Planet

An Earth Analog Planet is an extrasolar goldi-locks planet with environmental conditions similar to those found on the planet Earth.

• AKA: Earth Twin.
  • …
• Counter-Example(s):
  • an Extrasolar Hot Earth-like Planet.
  • an Extrasolar Cold Earth-like Planet.
• See: The Earth.

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References

2013

• http://en.wikipedia.org/wiki/Earth_analog
  • An Earth analog (also referred to as a Twin Earth, Earth Twin, Second Earth, Alien Earth, Earth 2 or Earth-like planet) is another planet (or world) with environmental conditions similar to those found on the planet Earth.

    The possibility is of particular interest to humans as it is easily inferred that the more similar a planet is to Earth, the more likely it is of sustaining Earth-like complex extraterrestrial life and civilization. As such it has long been speculated and the subject expressed in science, philosophy, science fiction and popular culture. Advocates of space colonization have long sought an Earth analog as a "second home" while advocates for space and survival would regard such a planet as a potential "new home" for mankind.

    Before the scientific search for and study of extrasolar planets, the possibility was argued through philosophy and science fiction. The Mediocrity principle suggests that planets like the Earth should be common in an infinite universe, while the Rare Earth hypothesis suggests that they are extremely rare. Philosophers have pointed out that the size of the universe is such that a near identical planet must exist somewhere, such theories include the philosophy of Multiverse and the Twin Earth thought experiment.

    Some scientific theories speculate that Earth analogs may have existed in our Solar System in the past. In the future, technology may be used by humans to artificially produce an Earth analog. In theory, terraforming could potentially create such a world. Multiverse theory suggests that an Earth analog could exist in another universe or even be another version of the Earth itself in a parallel universe.

    On November 4, 2013, astronomers reported, based on Kepler space mission data, that there are an estimated "40 billion" habitable Earth-like planets orbiting sun-like stars within the Milky Way Galaxy. The nearest such planet may be 12 light-years away according to the scientists.

    Recent scientific findings have greatly influenced the scope of the fields of astrobiology, models of planetary habitability and the Search for Extraterrestrial Intelligence. NASA and the SETI Institute have proposed categorising the increasing number of Earth-like planets found using a measure called the Earth Similarity Index (ESI) based on mass, radius and temperature. According to this measure, the planet currently thought to be most similar to Earth is Gliese 667C c (0.85).

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