This dish antenna rises seven stories above an ancient seabed in the Karoo, a remote semidesert in South Africa. Later this year it will start scanning the universe for radio waves emanating from charged particles billions of light-years away, probing some of science's deepest questions: Was Einstein right about gravity? What are the origins of magnetism? Are we humans alone? The 50-foot-wide dish, though, will have friends. It's among the first of up to 3,000 dishes that will eventually spread from South Africa into eight additional African countries. That spiraling array of mid-frequency dishes will join up to 1 million much smaller low-frequency antennas planned for Australia. Combined, they'll form a single observatory called the Square Kilometre Array, the largest scientific structure on the planet, to gather 10.8 million square feet of radio waves.
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