Posted on Monday, April 13th, 2009By Erik Van Datiken 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." 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. 5. TOP-SHAPED. Reminiscent of a child's toy top, this craft is fat in the middle and tapered above and below. It's covered in multicolored lights. Powerful jets around its midsection move the UFO in any direction. "Round portholes often ring the vehicle. The body is often said to be grayish, like a shark's skin." 4. COIN-LIKE DISK. Shaped like a giant 50-cent piece, this UFO is the type most often reported by military and airline pilots flying at 20,000 to 40,000 feet. Eyewitnesses say the flat edger of the disk often is ringed with red or green lights. The spaceship is incredibly fast, zipping along at speeds of more than 2,500 MPH. "The craft has been estimated at 15 to 20 feet in diameter and 2 to 3 feet high." 3. FOOTBALL-SHAPED. This craft has a thick black body that tapers off at either end. Smaller UFOs have reportedly been seen entering and leaving a bay on its lower surface - so it's also often called a "mother ship." Reports have placed the craft's size at up to 80 feet long and 20 feet high. 2. CONICAL DISK. This UFO resembles a Chinese peasant's large straw hat. It has a flat bottom. The craft is generally reported as being about 20 feet in diameter and 10 to 12 feet high at the peak, with no exterior lights.