a bonobo humanity?

I’ve generally thought that the extraordinary volume of water on our planet’s surface was a problem, scientifically speaking, but I’m probably wrong. I used to think that the idea that water came to Earth in meteor showers (haha) couldn’t be right, because the days of Earth’s heavy bombardment came early in the planet’s history when everything was molten hot and the water or ice from meteors would’ve just boiled away. But what would I know? And why would meteors, or planetesimals, be so full of water?

As the astronomers are constantly telling me, water in solid, liquid and gaseous form is commonplace in our solar system, our galaxy, our universe. In the habitable zones of our universe it can exist in all three forms close together, and that’s what presumably makes those regions habitable. On Earth we have a hydrological cycle – evaporation and transpiration, condensation, and precipitation – involving the three forms of this precious stuff, more or less. Recently, some fuss was made about water found in the atmosphere of a not-so-distant exoplanet, and the female interviewer was seemingly excited about – hey, water, and maybe life!!! – but the scientist was much more impressed by the detection abilities we’ve developed for working out the chemical signature coming from distant bodies (this one was about 100 light years away – our galaxy is many thousands of light years across). Water in the atmosphere and even on the surface of these bodies is unsurprising, apparently. 

When you (I mean I) consider that hydrogen is the simplest and most abundant element in the universe, and oxygen is also a relatively simple and abundant molecule, we shouldn’t be surprised that water is commonplace. As the above-mentioned scientist pointed out, water is found in the interstellar medium between star systems, amongst gas clouds, and within our solar system, especially in the material of the Kuiper Belt and in the ‘ice giants’, Neptune and Uranus. More excitingly for the possibilities of life, liquid, flowing water has been found on Mars – albeit highly salinated and mineral-rich. There’s still a possibility, though, that less ‘contaminated’ water may be found nearer the Martian poles. It’s also seen as a sign that Mars is drying up, water-wise, that it was once a much more watery world, and for a long time. Could it have seeded life on Earth?

Water worlds are being found elsewhere in the solar system too. The Cassini spacecraft has made major discoveries about Enceladus, a tiny, very bright moon of Saturn. Jets of water vapour, ice and surprisingly large quantities of organic chemicals burst out from below the moon’s icy crust at tremendous velocity. Some of the material is added to Saturn’s particulate ring system. The E ring’s particles, where the Enceladus material ends up, have been examined by Cassini, and in short, the examination suggests that there are hydrothermal vents beneath the icy shell of the moon, similar to those underneath the Pacific Ocean. Cassini’s analysis has also strongly indicated an ocean with a depth of around 10 kilometres underneath the thick ice (30-40 kms) at the southern polar region.

There are other promising watery discoveries too, and a relatively new theory about water on Earth, which I’ll leave for another post.

References

NASA discovers a water world in our solar system (mashable video)

https://imagine.gsfc.nasa.gov/features/cosmic/milkyway_info.html

https://solarsystem.nasa.gov/missions/cassini/science/enceladus/

How did Earth get its water?