What was the size of the Smallest Object in Outer Solar System Spotted (SPACE.com)?
In a cosmic version of the old needle-in-a-haystack finding, astronomers have spotted an object less than a mile wide that is 4.2 billion miles away, in the outer solar system. The object is part of the Kuiper Belt, an ring of icy rocks beyond Neptune. The object, spotted in visible light by the Hubble Space Telescope, is about 3,200 feet (975 meters) across. Previously, the smallest object seen via reflected visible light in the Kuiper Belt was 30 miles wide. The discovery, though small, is the first observational evidence for a population of comet-sized bodies in the Kuiper Belt that are being ground down through collisions, astronomers said. The Kuiper Belt is therefore collisionally evolving, meaning that the region’s icy content has been modified over the past 4.5 billion years, since the solar system was born. Interestingly, the object is actually 100 times dimmer than Hubble can see directly. So the discovery was made by using a trick of light. Hubble has three optical instrumen
