请告诉我关于太阳系八大行星的简要信息，请以json格式输出，包含每个行星的名称、与太阳的距离（单位：百万千米）、直径（单位：千米），且字段名必须用英文。
user
{
  "planets": [
    {
      "name": "Mercury",
      "distance_from_sun": 57.91,
      "diameter": 4880
    },
    {
      "name": "Venus",
      "distance_from_sun": 108.21,
      "diameter": 12104
    },
    {
      "name": "Earth",
      "distance_from_sun": 149.6,
      "diameter": 12742
    },
    {
      "name": "Mars",
      "distance_from_sun": 227.92,
      "diameter": 6779
    },
    {
      "name": "Jupiter",
      "distance_from_sun": 778.57,
      "diameter": 139820
    },
    {
      "name": "Saturn",
      "distance_from_sun": 1433.5,
      "diameter": 116460
    },
    {
      "name": "Uranus",
      "distance_from_sun": 2872.5,
      "diameter": 50724
    },
    {
      "name": "Neptune",
      "distance_from_sun": 4495.1,
      "diameter": 49244
    }
  ]
}
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