There is compelling evidence to suggest the presence of water on Mars. Over the years, various missions and observations have provided valuable data supporting this claim. Here are some key pieces of evidence:
Martian Polar Ice Caps: Mars has permanent ice caps at its polar regions, composed mainly of water ice. These ice caps consist of a combination of water ice and carbon dioxide ice (dry ice). The polar ice caps have been observed to grow and shrink with the seasons, indicating a dynamic process involving water. Liquid Water Flows: In 2015, NASA announced the discovery of recurring slope lineae (RSL) on the slopes of Martian craters and cliffs. These dark streaks appear to form and grow during warm seasons and fade during cooler seasons. The behavior of RSL strongly suggests the presence of liquid water, although the exact source and nature of the water are still under investigation. Water Vapor in the Atmosphere: The Mars Atmosphere and Volatile Evolution (MAVEN) mission, launched in 2013, has provided valuable data on the Martian atmosphere. MAVEN detected and measured significant amounts of water vapor in the atmosphere, particularly during specific seasons and locations on Mars. This suggests that there are localized sources of water on the planet.
- What are Mars’ “seasonal seeps”?
- Also known as recurring slope linea, these “enigmatic streaks” appear as narrow, dark markings on many of Mars’ steep slopes and crater walls.
- What do scientists think is the source of Mars’ seasonal seeps?Probably the Martian atmosphere. In a process called deliquescence, “salts on the surface can absorb atmospheric water vapor and trap it in their crystal structures. Then, when the crystals warm up, they dissolve. The whole liquidy mix surrenders to the tug of gravity, and off it goes, tumbling downhill.”
- Other, less exotic possibilities include an underground aquifer or a buried ice field that thaws with the season. (No, the Martian ice cap is not melting.)
- Why is the identification of liquid water so important?
- The possibility of extraterrestrial life. According to Nat Geo, “What we know so far, based on the single example of Earth, is that life tends to show up wherever there’s water. That’s why NASA’s search for life beyond Earth has been driven by the mantra, ‘Follow the water.’”
- Why water?
- Water is [one of] our only naturally occurring inorganic liquids, the only one not arising from organic growth.
- Water dissolves just about anything.
- Water is the only chemical compound that occurs naturally on Earth’s surface in all three physical states: solid, liquid, and gas. Good thing, otherwise the hydrological cycle that most living things rely on to ferry water from the oceans to the land and back again would not exist.
- Water also has an extremely large liquid range. Pure water freezes at 0°C (32°F) and boils at 100°C (212°F). Add salt and you can lower the freezing temperature. Add pressure and you can raise the boiling temperature. . . [This means that temperatures] can undergo extreme variations—between night and day, say, or between seasons—without water freezing or boiling away.
- Unlike most other liquids when they freeze, water expands and becomes less dense. [Frozen water floats, not sinks.] If it sank, ice, being unable to melt because of the insulating layer of water above it, would slowly fill up lakes and oceans in cold climates, making sea life in those parts of the world a challenging prospect.
- Water plays another key role in the biochemistry of life: bending enzymes. Enzymes are proteins that catalyze chemical reactions, making them occur much faster than they otherwise would. To do their handiwork, enzymes must take on a specific three-dimensional shape. Never mind how, but it is water molecules that facilitate this.
- Why liquid?
- The biochemical reactions that sustain life need a fluid in order to operate. In a liquid, molecules can dissolve and chemical reactions occur. [Liquid also] effectively conveys vital substances . . . from one place to another, whether it’s around a cell, an organism, an ecosystem, or a planet
- #WaterOnMars
- #MartianWater
- #MarsH2O
- #LiquidWaterOnMars
- #MarsPolarIceCaps
- #RSLonMars (Recurring Slope Lineae)
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