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.

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。

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From June to October 1975, Russian space probe Venera 9 became the first craft to orbit, land on, and photograph Venus.

1975年6月- 10月，俄罗斯金星9号探测器第一个绕金星轨道运行，着陆，拍摄的航天器。

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The Venus Express probe discovered hydroxyl in the clouds that shroud the planet.

金星快车探测器在金星高空发现了羟基，并且覆盖着星球。

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It includes, for example, the case of Mariner 1, an unmanned Venus probe launched in July 1962.

ECONOMIST: Mishaps in space: Foolish, not ghoulish | The

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.

ECONOMIST: An argument over whether to send messages to aliens

In 1962, the Mariner II space probe began sending back to Earth man's first information from another planet, Venus.

CNN: Monday,