请列举出五部你认为最经典的科幻电影，并以json格式进行回答。
user
```json
{
  "classic_sci_fi_movies": [
    {
      "title": "银翼杀手",
      "year": 1982,
      "director": "雷德利·斯科特"
    },
    {
      "title": "2001太空漫游",
      "year": 1968,
      "director": "斯坦利·库布里克"
    },
    {
      "title": "星球大战",
      "year": 1977,
      "director": "乔治·卢卡斯"
    },
    {
      "title": "异形",
      "year": 1979,
      "director": "雷德利·斯科特"
    },
    {
      "title": "终结者2：审判日",
      "year": 1991,
      "director": "詹姆斯·卡梅隆"
    }
  ]
}
```
assistant