他认为，人类运用雷达天文学探测小行星和金星等天体，早已经发射出可以被外星智慧生物接收到的信号。

He argues that radar astronomy, which is used to probe things like asteroids and the surface of Venus, already gives off signals that could be picked up by aliens.

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NASA的雷达天文学家周五发现了它的轨迹，并立即将它的位置精确至一公里以内的区域，比此前最好的估计精确了50倍。

NASA radar astronomers picked up its track on Friday and were immediately able to narrow its position to within one kilometer — 50 times better than their previous best estimate.

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该技术在射电天文学、卫星雷达和机载雷达上均获得了巨大成功。

The technique has been highly successful in radio astronomy, and in both satellite and aircraft borne radar.

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