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How many Kuiper belt objects may be larger than 1 kilometer across?

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Kuiper belt binary object — Kuiper belt An artist's rendition of a binary object in the Kuiper belt. The two objects depicted orbit each other at the edge of the solar system.

The number of Kuiper belt objects (KBOs) larger than 1 kilometer in diameter is highly uncertain, as current estimates rely on extrapolations from a limited sample of detected sources.1

If the relationship between the number of objects and their size in the Kuiper belt is similar to that of asteroids—which include an estimated 1 million objects larger than 1 kilometer—it implies a total population of more than 100 billion KBOs larger than 1 kilometer in diameter. However, because this figure is derived from only a few hundred observed sources, it remains subject to considerable uncertainty.1