There has been much excitement generated in the past week around the discovery of a planet circling a red dwarf star just 20 light years from Earth that appears to be located within a habitable zone, what scientists refer to as the “Goldilocks Zone.” According to the New York Times, new planet, Gliese 581g, is the sixth planet discovered in the red dwarf’s planetary system and is far closer to its star than Earth is to the Sun, but scientists believe that it just might be in the “just right” category of planets that could potentially sustain life.
“This is the first exoplanet that has the right conditions for water to exist on its surface,” noted Steven S. Vogt of the University of Caifornia-Santa Cruz. Vogt, along with R. Paul Butler of the Carnegie Institution of Washington, led the team that discoverd Gliese 581g.
Gliese 581g orbits its star, which is situated in the Libra constellation, about 14 million miles out (as opposed to Earth orbiting the Sun at 93 million). It is believed that it might sustain life because the red dwarf star it orbits emits light at about one-third the strength of Sol. According to Vogt and Butler, Gliese 581g orbits nearly in the center of the “Goldilocks Zone,” the area in a star’s orbital field that is most conducive to sustaining life. The newly discovered planet revolves around its star every 37 days, rotating so slowly that one side nearly always faces its sun.
The discovery of Gliese 581g was announced at a press conference in Washington, D. C., Wednesday. The results of the research have been posted on the National Science Foundation’s website and will be published in The Astrophysical Journal.
Although reluctant to commit to certainty about the possibility of the existence of extraterrestrial life on the new planet, Steven S. Vogt told reporters that, personally, he believed “the chances of life on this planet are almost 100 percent.”
R. Paul Butler was far more circumspect. “I like data,” he said, paused, then continued, “and what the data say is that the planet is the right distance from the star to have water and the right mass to hold an atmosphere. What is needed simply to find lots and lots of these things is lots and lots of telescope time.”
Gliese 581g isn’t the only planet circling Gliese 581 that swings around its star in the “Goldilocks Zone.” Two others, one on the inner edge and the other on the outer, also are positioned within the habitability area. However, both of those worlds are believed to be at the extreme limits for sustaining extraterrestrial life.
The discovery has caused intense excitement within the scientific community for more reasons than its position relative to its star. Its proximity to Earth, just over 20 light years distant, leads many to believe that there could be an enormous number of extrasolar planets that could be Earth-like — or at least life-sustaining in some manner — not only in Earth’s relative galactic neighborhood but through the galaxy and the rest of the universe.
If Gliese 581g is not an exception, its relative proximity to our solar system could go far in lending credence to Drake’s Equation — the mathematical formula proposed by Dr. Frank Drake, the University of California, Santa Cruz astrophysicist who suggested that there could be at least 10,000 Earth-like planets that might contain life and which could potentially have the capability of communicating with the Earth.
“Either we have just been incredibly lucky in this early detection, or we are truly on the threshold of a second Age of Discovery,” the team wrote in their discovery submission to The Astrophysical Journal.
The first extrasolar planet ever discovered was 51 Pegasi b, its existence announced in October 1995. Although at first thought to have terrestrial characteristics, the planet is now believed to be a gas giant.
According to the Interactive Extra-Solar Planets Catalog, nearly 500 confirmed extrasolar planets have been discovered to date.
Of them all, only Gliese 581g seems to have many of the conditions necessary to sustain habitability. Whether or not that equates to actual living organisms and even intelligent extraterrestrial life remains to be seen.