It's not uniformly distributed ... it's not like it's hiding in the dirt and we just didn't see it. |
The common expectation was that water would be all over the surface. But what we found was that it was in small, discrete areas. |
These results show that there is ice on the surface, but not very much and definitely not enough to account for the water we see in the out-gassed material that is in the coma [the cloud of gas and dust that surrounds the comet]. |
Understanding a comet's water cycle and supply is critical to understanding these bodies as a system and as a possible source that delivered water to Earth. |
We have known for a long time that water ice exists in comets, but this is the first evidence of water ice on comets. |