WASHINGTON, May 8 : Astronomers have gotten their clearest look yet at the surface of an exoplanet - a planet beyond our solar system - thanks to NASA's James Webb Space Telescope. Webb gathered data on a rocky exoplanet with a diameter about 30 per cent larger than Earth that indicates it is a desolate and airless world whose surface may resemble that of Mercury, our solar system's innermost planet. Its lack of a discernible atmosphere and its extreme temperatures - fiercely hot on one side