A mother ship resembling a giant football, a whirling coin-shaped disk that flashes across the sky, a diamond-shaped craft with a brilliant, mirror-like surface…

These are among the most common UFO shapes, according to veteran UFO researcher Brad Steiger, author of Mysteries of Time and Space.

Here are detailed descriptions based on Steiger’s analysis of several thousand sightings over the past 40 years:

8. BLINDING LIGHT. Typically spotted at night, this UFO doesn’t have a definite shape – it’s simply a dazzling orange light. “But it moves methodically, as if guided by some form of alien intelligence.”

7. DIAMOND-SHAPED. This craft resembles the top half of a diamond mounted on a flat surface. Its exterior is polished and as dazzling as a mirror in bright sunlight. The UFO usually is about 18 feet across and 8 to 10 feet high. It has no portholes or windows.

6. EGG-SHAPED. This massive vehicle, thought to be a “mother ship” – has been reported to be up to 200 feet in length. It has an oval shape like an egg, with no visible portholes or windows, and glows slightly in the dark.