But current estimates of the number of icy fragments in the outer reaches of our solar system suggest that the night sky should be bright.
Current theories propose that the abundance of the objects grows exponentially as the size falls.
But if very small objects are as common as this suggests, these Kuiper belt objects would violate Olbers' principle - that is, they would make the night sky bright. They analysed existing counts of larger KBOs and measurements of optical and infrared radiation from smaller objects to establish more accurately their size distribution. This in turn provides clues about evolution in the early solar system. But for objects less than a kilometre across, the distribution is much shallower - resulting in fewer very small fragments. This discovery is consistent with classical theories of how particles collided and merged in the disk of gas and dust orbiting the Sun before the planets coalesced.