Fact Check: Water in space quickly evaporates into water vapor, it quickly freezes. Now it depends on how close you are to the Sun or whether you are hidden from it when it comes to what happens next. Close to the Sun, in full sunlight water would eventually vaporize. That's why on Mercury and the Moon, ice only exists in permanently shadowed craters. But because the outer solar system is far from the Sun, ice can exist on the surface without any problems.

Fact-Check Article: Water in Space and Its Behavior on the Moon and Mercury

What We Know

The claim states that water in space quickly evaporates into vapor and can freeze depending on proximity to the Sun. Specifically, it mentions that on Mercury and the Moon, ice exists only in permanently shadowed craters due to the extreme conditions in these areas.

1. Evaporation and Freezing of Water in Space: Water does indeed evaporate quickly in the vacuum of space, particularly in areas exposed to sunlight. This is due to the lack of atmospheric pressure, which allows water molecules to escape into vapor more readily than they would on Earth. In contrast, when water is shielded from sunlight, such as in permanently shadowed craters, it can remain frozen for extended periods. This phenomenon has been confirmed through various studies and missions (NASA's Moon Water and Ices).

2. Presence of Ice on the Moon and Mercury: Research has shown that both the Moon and Mercury contain water ice, particularly in permanently shadowed regions. For instance, studies have indicated that the Moon has ice deposits in craters that never receive sunlight, which can preserve ice for billions of years (NASA's analysis of ice deposits). Similarly, Mercury has been found to have significant ice deposits in its polar regions, which are also shielded from the Sun (NASA's MESSENGER mission).

3. Water on the Sunlit Surface of the Moon: Contrary to the claim that water only exists in shadowed areas, recent findings have confirmed the presence of water on the sunlit surface of the Moon. Data from NASA's SOFIA mission revealed that water exists in sunlit areas, albeit in lower concentrations compared to permanently shadowed regions (NASA's 2020 findings).

Analysis

The claim presents a mixture of accurate and misleading information.

• Accuracy of Evaporation and Freezing: The assertion that water evaporates quickly in sunlight and can freeze in shadowed areas is supported by scientific evidence. The behavior of water in space is well-documented, particularly regarding its phase changes in response to temperature and pressure conditions (NASA's Moon Water and Ices).

• Ice Existence on the Moon and Mercury: The claim accurately notes that ice exists in permanently shadowed craters on both the Moon and Mercury. This is corroborated by multiple studies, including data from NASA's Lunar Reconnaissance Orbiter and MESSENGER missions, which have identified ice deposits in these regions (NASA's analysis of ice deposits, NASA's MESSENGER mission).

• Misleading Implication About Sunlit Areas: However, the claim's implication that water cannot exist outside of shadowed regions is misleading. Recent discoveries have shown that water does exist on the sunlit surface of the Moon, which contradicts the assertion that ice is exclusively found in shadowed craters (NASA's 2020 findings). This indicates a more complex understanding of water distribution on the Moon than the claim suggests.

• Source Reliability: The sources cited in this analysis are credible, coming from NASA and peer-reviewed studies. NASA's missions and findings are widely recognized in the scientific community, lending significant weight to the information presented.

Conclusion

The claim is Partially True. While it accurately describes the conditions under which water behaves in space and acknowledges the existence of ice in permanently shadowed regions on the Moon and Mercury, it fails to account for the recent evidence of water on the sunlit surface of the Moon. This oversight leads to an incomplete understanding of the distribution of water in these celestial bodies.

Sources

1. Moon Water and Ices
2. The Moon and Mercury May Have Thick Ice Deposits
3. NASA Spacecraft Finds New Mercury Water Ice Evidence
4. Lunar water
5. Development of icy regolith simulant for lunar permanently shadowed regions
6. Shallow Craters on Moon and Mercury May Hide Thick Slabs of Ice
7. Mercury's Polar Ice Defies the Odds
8. Ice at the Lunar Poles