Superman hails from a planet called Krypton, an Earth-like planet of (superpowered) Earth-like people. As the story goes, his father, a Kryptonian scientist named Jor-El, predicted that the planet of Krypton would explode, wiping out everything. Seeing disaster looming, Jor-El explored the universe for another habitable planet, finding Earth in his investigation. He built a prototype space shuttle and passionately argued that the planet mobilize around a wide-scale evacuation plan, as seen here, from the 1950s television show The Adventures of Superman. The argument fell on deaf ears, but Jor-El was able to put his son, Kal-El (who we call Clark Kent/Superman) in the prototype shuttle just moments before Krypton self-destructed.
Superman, sorry to say, is a work of fiction. But habitable planets outside our solar system? They are likely real.
The picture above is not of the Sun and the Earth — or, for that matter, of Krypton. It is an artist’s rendition of the star Gliese 581 and a planet, Gliese 581 g. Gliese 581 is a red dwarf star — a small, relatively common star type — located approximately 20 light years away from Earth. Planet “g” is the fourth planet (located so far) in orbital distance from the star, between planets “c” and “d.” It was given the label “g” because it is believed to be in the center of Gliese 581′s “Goldilocks zone” — a swath of space which is not too hot, not too cold, and in which planets can maintain life. Gliese 581 g is the first such habitable planet thus discovered, but the relative ease in identifying it suggests that as many as 10% of stars have habitable planets.
Does that mean Earthling colonization — even in a last-ditch, Kryptonian-like effort — is in Gliese 581 g’s future? Hardly. Even if humanity came up with a space craft which could travel at one percent of the speed of light — 6.7 million miles per hour, or about 9,000 times faster than the speed of sound — it would take us over 2,000 years to get there. That is, if Jesus left for Gliese 581 g (at that speed) the day he died, he would arrive there in about 20 to 25 years from now.
Bonus fact: There are 180 episodes of Seinfeld. Of those, no fewer than 120 have at least one reference to Superman.
From the Archives: The Swedish Solar System: The country of Sweden is — is, not has — a scaled-down model of the Solar System.