Other Worlds

One of the most exhilarating results in modern astronomy is the knowledge that the Universe is full of worlds beyond our Solar System, known as exoplanets. Increasing evidence suggests that the majority of stars in the Universe have planets whizzing around them; one such system can be seen in this majestic Picture of the Week. 

The antennas here are among the 66 that make up the Atacama Large Millimeter/submillimeter Array (ALMA), located on the Chajnantor plateau in Chile. Two bright stars sit directly above the centre antenna; the brightest of these two stars is a triple star system known as Alpha Centauri. An exoplanet named Proxima b was recently discovered orbiting within the habitable zone of one these three stars (Proxima Centauri) by ESO telescopes and other facilities. As Alpha Centauri is the closest star system to Earth, Proxima b is the closest exoplanet to Earth ever discovered.

Another world can be seen in this stunning sky — this time, one a little closer to home. At the top of the image, two bright, reddish objects sit just outside the main river of the Milky Way. The one on the left is Antares — a red giant star in Scorpius — and the one on the right is Saturn, the spectacular ringed gas giant planet.