Fact-Check: "On the moon, exposed liquid water wouldn't freeze during the day but evaporate into vapor"
What We Know
The claim that "on the moon, exposed liquid water wouldn't freeze during the day but evaporate into vapor" is based on the understanding of the Moon's environment. The Moon has a very thin atmosphere, which means that any liquid water exposed to the lunar surface would not behave as it does on Earth. According to NASA, the lack of atmospheric pressure on the Moon causes water to evaporate almost instantly when exposed to sunlight. This phenomenon occurs because the boiling point of water decreases in lower pressure environments, leading to rapid vaporization even at relatively low temperatures.
Additionally, research has shown that there are areas on the Moon, specifically in permanently shadowed regions (PSRs), where water ice can exist without evaporating. A study led by the University of Hawaiʻi found direct evidence of surface-exposed water ice in these PSRs, indicating that while water can exist in solid form, it is not stable as liquid water on the lunar surface during the day (UH News).
In 2020, NASA confirmed the presence of water in sunlit areas of the Moon, but this water is not in a liquid state; rather, it exists as water molecules embedded in the lunar soil (NASA's SOFIA mission).
Analysis
The claim hinges on the behavior of water in the Moon's unique environment. The assertion that exposed liquid water would evaporate rather than freeze is consistent with scientific understanding of the Moon's conditions. The Moon's lack of atmosphere means that any liquid water would quickly transition to vapor due to the low pressure, as noted by Wikipedia.
However, the claim lacks nuance regarding the temperature variations on the Moon. While it is true that water would evaporate quickly in sunlight, the Moon experiences extreme temperature fluctuations, with nighttime temperatures dropping significantly. This means that if liquid water were to exist during the day, it would indeed evaporate, but it could potentially freeze at night in shaded areas.
The reliability of the sources used to evaluate this claim is high. NASA's findings are based on extensive research and data collection, while the study from the University of Hawaiʻi provides direct evidence of water ice, reinforcing the understanding that water can exist in solid form in certain lunar conditions (UH News). However, the claim itself oversimplifies the complexities of lunar water behavior, particularly by not addressing the conditions under which water might freeze or remain stable.
Conclusion
The claim that "on the moon, exposed liquid water wouldn't freeze during the day but evaporate into vapor" is False. While it is true that liquid water would evaporate rapidly due to the Moon's low atmospheric pressure, the assertion ignores the potential for freezing under different conditions, such as during the lunar night or in permanently shadowed regions. Moreover, the existence of water in solid form (ice) has been confirmed, indicating that the lunar environment allows for various states of water, but not in the form of stable liquid under direct sunlight.
Sources
- Moon Water and Ices
- Direct evidence of ice on Moon surface discovered
- Lunar water
- Yes, There's Ice on the Moon—But How Much, and ... - Science
- Exploring the lunar water cycle - PNAS
- Unlocking the Mystery: Why will Water Boil on the Moon?
- How Can There Be Ice On The Moon?
- Water vs. the Moon: What Happens When Liquid Meets Lunar ...
