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Western Slope Skies - Water On Planets


Mars - The next frontier.

Provided we can do something with it, and the ice that’s currently present on the planet.

Water is critical when searching for a suitable new colony beyond Earth. Liquid water is critical, because it’s one of three major building blocks for life- the other two being an energy source and organic compounds from which biological molecules can be built.

Evidence of liquid water beyond Earth could indicate an environment that can sustain life for humans or other beings. Using rovers and telescopes, we can look for that life-sustaining fluid on other worlds. Scientists have been searching within our own solar system for water. One of Jupiter’s moons, Europa, has been a hot topic for this search. Scientists are certain that beneath Europa’s already icy surface is a liquid water ocean that may contain twice the volume of water as Earth. There is also evidence that one of Jupiter’s other moons, Ganymede, has a large saltwater ocean beneath its surface

As of 2019, astronomers have found many planets outside of our solar system, called exoplanets, which have the potential to contain liquid water. One such planet, K2-18b, located 124 light years away from Earth, orbiting around a red dwarf star, has had water vapor detected in its atmosphere by analysis done with the Hubble Space Telescope. Detecting water vapor is important because it plays a critical role in stabilizing the surface temperature of a planet, since it is a greenhouse gas. Under the right conditions, water vapor in Earth’s atmosphere condenses to form liquid water that rains down onto the surface. Exoplanet K2-18b orbits at the ideal distance from its star to have the temperature needed, but it is not yet confirmed whether this planet has liquid water on its surface.

The detection of water on planets outside our solar system has turned out to be both scarce and common, depending on the type of planet. Studies of atmospheric data for 19 exo-planets ranged from 10 times Earth’s mass to over 600 times Earth’s mass. 14 of these planets were found to have an abundance of water vapor; most of these were larger gaseous planets. Smaller, rockier planets had minimal water vapor in their atmospheres. This means that exo-planets are more complex and diverse than initially thought, and the search for habitable planets can be significantly broadened.

Mars may be the first planet that humans colonize outside of Earth, but planets beyond our solar system may be much more similar to our home. If only we can find a way to get out there.


Western Slope Skies is produced by the Black Canyon Astronomical Society. This feature was written and recorded by Justin Murphy, an astronomy student of Dr. Catherine Whiting at Colorado Mesa University.