After no small amount of mystery, we're starting to understand more about 'Oumuamua, the first known interstellar object to visit the Solar System. A newly published study indicates that the object can't be that large, for one thing. As the Spitzer Space Telescope's infrared detection couldn't catch the cigar-shaped entity, that makes it relatively small. It's likely less than half a mile (2,600 feet) at its longest. It also can't have a diameter larger than 1,440 feet, and that figure could be as small as 320 feet.