A few days ago, the European Southern Observatory discovered the first possible Earth-like planet orbiting another star, Gliese 581 (also known as “HO Librae”). Gliese 581 is a red dwarf star — about 1/3 the size of our own sun, and about 100 times dimmer. HO Librae shines red in the sky above the the newly-discovered planet, “Gliese 581 c.” The planet has a year of only 13 days. Because it is so close, its sun would appear to be more than 4 times bigger than our sun, even though it is a smaller star. There is also known to be a neptune-like planet in the Gliese 581 system, “Gliese 581 b,” and scientists suspect there is at least one more planet as well (“Gliese 581 d”).
Gliese 581 c is five times as massive as the Earth and lies in it’s sun’s habitable zone, meaning that it is just the right distance for there to be liquid water on the surface. Further details on the planet are educated guesses, but the staff at the European Southern Observatory have put forth a few.
Gliese 581 c is probably a rocky world, and not a gas-giant. It’s diameter is probably 1.5x the Earth’s, which means that you would weigh roughly 2.2 times more on the surface than you do on Earth. The atmospheric temperature on the surface of Gliese 581 c could very well be between 0 and 40 degrees Celsius, quite conductive to life.
There are still many unknowns, however. For example, Gliese 581 c might have a harsh, Venus-like atmosphere of greenhouse gasses which might cook the planet’s surface to hundreds of degrees. Possibly, it even has no atmosphere at all. Because we don’t have any clear pictures of the planet, no one knows exactly what the planet is made out of, although you can bet that many observatories will be focusing on the Gliese 581 system in order to try and catch a glimpse of the planet.
Also, while we are currently struggling to launch missions to the moon, and Mars, most of those issues are political rather than technical. Look at China, Japan, and India. While the US private sector is making some progress, much more needs to be done, and with a serious budget commitment. Gliese 581 is only 20 light-years away. By galactic standards, it’s a close neighbor. In fact, we have the technology today to send a probe which would arrive in only a few hundred years. Before long, we’ll be able to get there much quicker.
One of the reasons the space race faltered after reaching the Moon in the 60’s was because we found out there was no place interesting to go. Now that we’ve found a planet that may support Human life, we will be more motivated to check it out.