| on the ground | 5 | location |
| to the naked eye | 4 | transitive-object |
| during night | 2 | temporal |
| ufo → be → invisible | 8 |
| ufo → become → invisible | 4 |
| negative | neutral | positive |
| 0.225 | 0.693 | 0.081 |
| Raw frequency | 12 |
| Normalized frequency | 0.296 |
| Modifier score | 0.700 |
| Perplexity | 56.590 |