Mercury’s Ice Likely Deposited by Single Massive Impact
SkimNews Take
A single, large impact event may have been sufficient to deliver and sequester a significant portion of Mercury's water, suggesting that the presence of polar ice on airless bodies could be less dependent on continuous cometary bombardment than previously thought.
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- Mercury has permanently shadowed craters at its poles containing ice several metres deep, as measured by NASA’s Messenger spacecraft.
- Parvathy Prem and colleagues simulated that a large, slower impactor creating the Hokusai crater could have vaporized and produced a thin water‑rich atmosphere on Mercury.
- Impact could have deposited over one‑fifth of its water vapor into Mercury’s poles within a single Mercurian day (176 Earth days), matching Messenger’s ice measurements.
- Emily Costello noted that this event would have been the most eventful day in Mercury’s last billion years.
- Hokusai crater is the visible result of the impact that delivered water to Mercury’s poles.
Why it matters: Planetary scientists gain a concrete mechanism for Mercury’s polar ice, refining models of inner‑planet water delivery and resolving a decades‑long puzzle that will shape future mission planning for Mercury and other air bodies.
