| Answer | Crossword Clue |
|---|---|
| EARTH | "The Blue Marble" subject |
| EARTH | The so-called "blue marble" |
| EARTHDAY | Its flag depicts the Blue Marble |
| EARTH | "Blue marble" |
| RANCE | Marble with blue-and-white markings. |
| DANUBE | Strauss's blue subject |
| SAPPHIREDMAN | Blue Frost subject? |
| SUNDAY | Blue law subject |
| SUNDAY | Blue-law subject |
| UFO | Project Blue Book subject |
| UFOS | Project Blue Book subject |
| UFOS | Project Blue Book subject (4) |
| UFOS | Subject of Project Blue Book |
