New Planet May Harbor Life
The First Earth-Like Habitable Exoplanet Has Been Discovered
Apr 25, 2007
The discovery was made by a team of European scientists, including one astronomer, Michel Mayor, who was also on the team that discovered the first planet outside our solar system. This new planet, named Gliese 581 c, circles a star named Gliese 581 which is 20.5 light-years away in the direction of the constellation Libra.
New Planet May Be Like Earth
The planet is a smaller and possibly rocky or watery world that lies just the right distance from its star to create a temperature of 0 to 40 degrees Celsius. This temperature, which translates to 32 to 104 degrees Fahrenheit, is right within the range of temperatures found on Earth and is needed for liquid water to form. Liquid water is seen as key for the creation and sustaining of lifeforms.
A Red Dwarf Planetary System
Not much else about the planet would seem Earth-like to a casual observer. Gliese 581 c does not orbit a star like the sun but instead orbits a red dwarf. A red dwarf is a small, cool, and dim star. Because it has less solar output, the habitable zone for a planet would be closer to a red dwarf, and that is where Gliese 581 c was found, so close that it orbits its star in only 13 days. Red dwarfs, although hard to see because of their size and temperature, are actually the most common type of star in the galaxy. Of the 100 stars closest to Earth, 80 of them are red dwarfs ... and Gliese and its new-found planet are one of those 80.
The newly discovered exoplanet is also about 50% larger than Earth yet it is the smallest one to be discovered to date. Gliese 581 c is part of a stellar (solar) system. There are at least three planets in total around Gliese 581. The first was found two years ago and it is a Neptune-mass planet. The mass of planet "c" is about five times more than that of Earth; therefore if you were to visit this planet you would weigh a lot more there because of its stronger gravity.
Because of the bright companion stars and smallness of the planets that orbit them, it has been very difficult to detect planets around other stars. But the dimness of red dwarfs makes this task a bit easier, and their abundance allows for many potential Earth-like targets. With future discoveries we may find that both sun-like stars and their smaller cousin, the red dwarf, are brimming with planets that may possibly be habitable.
One Step Closer to Answers
At its core, the questions of astronomy could always be boiled down to "Why are we here? How did we get here? and Are we alone?" These questions are one step closer to being answered after the discovery of the first Earth-like planet outside our solar system.
