在地球上，慢跑者只要几个小时就能完成马拉松。但在火星上，花了 11 年之久。美国航空航天局的机会号探测器在 2015 年越过了终点线。 访问 http://science.nasa.gov/ 了解更多信息。 点击这里查看更多视频：https://alugha.com/NASA 这段视频是 2015 年
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Visit http://science.nasa.gov/ for more. Earth is surrounded by electrons that can be disruptive to our technology. NASA is using high-altitude balloons and spacecraft to monitor and understand these particles in the radiation belts surrounding our planet. Click here to see more videos: https://al
Explore how astronomers and scientists use astronomical units to measure distances in the solar system in this video adapted from NASA. The astronomical unit (au) -- equal to the average distance from Earth to the Sun -- is a convenient unit of measure when talking about distances in the solar syste
