Astronomers struggle to find life beyond (and within of course) our solar system. The problem is though, that - should they want to fins life beyond our solar system, first they have to find a solar system, and to find a solar system, planets must be found first. The first exoplanet around a Sun-like star was found by the same team back in 1995 and since then there have been more than 800 confirmed discoveries.
Searching for alien planets is not as easy as sticking the eye onto the eyepiece of a telescope. THe problem is that a planet emits no light at all, and this planet usually orbits a bright star, completely outshining the planet. One method to find alien planets has been developed the last years and seems to work pretty well for large sized planets - usually the size of our own gas giants. Cutting long story short, if relatively large plane orbits a relatively small star, then center of gravity of the orbit is quite displaced from the star's center causing it to wobble as the large planet rotates. Scientists can see this wobble and calculate the planet's size and orbit.
Recently, European astronomers managed to locate for the first time, an alien planet which probably has similar mass to Earth. This planet orbits the closes star to our solar system, the star system Alpha Centauri, about 4 light years away. Alpha Centauri consists actually of 3 stars, namely the binary stars Alpha Centauri A and Alpha Centauri B and a more distant star known as Proxima Centauri. The newly discovered planet orbits Alpha Centauri B, a star slightly smaller than our sun in density and a little bit less bright.
The newly discovered planet, with a mass of a little more than that of the Earth. It orbits about six million kilometres away from the star, much closer than Mercury is to our Sun. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet's skies.
Due to its proximity, scientists since the 19th century believed that a solar system similar to ours might exist in Alpha Centauri. As a matter of fact, James Cameron was inspired as well and placed Jakesuli, Neytiri and the other Navi people to live in Pandora, one of the moons of the gas giant Polyfemos which orbits Alpha Centauri A. Far from true, such a planet could never orbit one of these starts because the gravitational force of the binary system would scatter any orbiting planet away in space. Only exception is the plane just found, which orbits extremely close to its sun, so the bond is very strong to break. This plane could never be Pandora though, since its surface roasts with a scorching 12,000 degrees Celsius.