“Because the dust grains are so small, they end up staying very cold so they can actually accumulate water,” Ishii said.
“Quantifying how much water is going to be a challenge, but it’s clear that because the influx of interplanetary dust particles is a continuing process that this can eventually become a significant amount of water just from cumulative buildup,” she said.
“It doesn’t just take a thunderstorm to fill up a lake. A continual light rainfall is also contributing to the water accumulation,” she added.
Potentially more important than how much water could have been produced and delivered by interplanetary dust grains is the organic carbon packaged along with it. Add heat from the dust grains entering Earth's atmosphere and the chemistry for life could begin to brew.
“We have this combination of water and organics being delivered simultaneously and continuously in a small volume where they are able to intermix and act like a little chemical reactor. It can generate compounds that are relevant to life being able to initiate,” Ishii said.
The same process could be happening on any solar system where hydrogen ions are spewing out in stellar winds.
"Water in the rims (of interplanetary dust grains) has implications for the origin of water on airless bodies like the moon and asteroids and delivery of water in other astrophysical environments," notes physicist John Bradley, with the Lawrence Livermore National Laboratory in California, and colleagues in a paper published in this week's Proceedings of the National Academy of Sciences.