2 April 2026
An ExTrA Sphere
While these two sunlit spheres share similarities in their shape and in being illuminated by the same star, they are vastly different. The one farthest away from the camera, hiding behind the clouds, is our own Moon, the Earth's only natural satellite. The other object is the dome of a telescope at ESO's La Silla Observatory, located on the outskirts of the Atacama Desert, in northern Chile.
The telescope is one of the three in the French project Exoplanets in Transits and their Atmospheres (ExTrA). ExTrA is focused on detecting Earth-sized worlds in the Milky Way. It relies on the transit method, in which planets block a fraction of the light from the star they orbit as they pass between the star and Earth, much like a partial eclipse. ExTrA centers on worlds orbiting red dwarfs – stars much smaller, colder, and dimmer than the Sun. Because red dwarfs are small, planets crossing in front of them block more light, making them easier to find than planets orbiting regular stars.
Who knows, perhaps some of these planets may look as otherworldly as the landscape of this picture. “These places compel me every time to think about our position in the Universe, putting my life ‘in context’ so to say,” says the photographer, ESO astronomer Luca Sbordone. “It always brings me peace.”
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