Because KBOs are so far away, fewer than 400 have been discovered out of hundreds of thousands thought to be the size of Massachusetts and perhaps billions as large as a city. Next to nothing is known about those that have been spotted. Other researchers who analyzed the new study said it implies that KBOs larger and more distant than Pluto will be found, and they'll be easier to spot because they will be brighter than expected. Break out the shades Varuna was discovered last November by astronomers using the Spacewatch telescope in Arizona. The new study of the object estimates how much sunlight Varuna reflects, a figure astronomers call albedo.
Dark objects reflect less light and have a lower albedo than light-colored objects.
Until now, researchers have assumed an albedo of 4 percent for all KBOs, a number based on the reflectivity of comet nuclei. Comets, thought to populate the Kuiper Belt and even more distant regions of space, only become bright when they cruise through the inner solar system, where the Sun burns off ice from the nucleus and creates a highly reflective halo. Otherwise, they are dark as charcoal. But Varuna turns out to be a real bright spot for KBO researchers. Jewitt and his colleagues used a technique often employed with asteroids, which are closer.