Mars lake was discovered using the MARSIS radar on board the "Mars Express" orbiter, and the profiles were collected between May 2012 and December 2015. The lake is centered at 193°E, 81°S, a flat area that does not exhibit any peculiar topographic characteristics. It is mostly surrounded by higher ground except on its eastern side, where there is a depression. Mars has two relatively small (compared to Earth's) natural moons, Phobos (about in diameter) and Deimos (about in diameter), which orbit close to the planet. Asteroid capture is a long-favored theory, but their origin remains uncertain. Both satellites were discovered in
Shepherd Moons and elements of Celtic and New age music, though Enya believes her music does not belong in the latter genre. "Shepherd Moons" received generally positive reviews from critics and became a greater commercial success than "Watermark". It went to number one on the UK Albums Chart and peaked at number seventeen on the "Billboard" 200 in the United States. The album was certified multi-platinum by the British Phonographic Industry and Recording Industry Association of America for shipments of 1.2 million and five million copies, respectively. Between 1991 and 1994, Enya released four singles from "Shepherd Moons": "Caribbean Blue", "How Can