美国宇航局研究太空旅行将如何对人体免疫系统产生影响。 访问http://science.nasa.gov/，了解更多。 功能性免疫故事：https://www.nasa.gov/mission_pages/station/research/news/functional_immune 点击这里看更多视频：https://alugha.com/NASA
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
