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Space News: Water worlds common, life likely?

Brian G Turner

Fantasist & Futurist
Staff member
Nov 23, 2002

A few recent space news stories to roundup:

1. Solar system 'normal'

One of the big mysteries is how usual or unusual our solar system is. We've identified a lot of exoplanets that are like nothing we've ever seen - and others that are commonly familiar.

Now a study looking at material around forming stars suggests that the basic ingredients of our solar system are actually pretty common: Study of material surrounding distant stars shows Earth's ingredients 'pretty normal'

This obviously suggests that the potential for life may be more common than expected, which leads us onto...

2. Water worlds are the norm

Computer modelling suggests that rocky planets larger than the Earth should routinely hold vast amounts of water, regardless of their orbits: Water-worlds are common: Exoplanets may contain vast amounts of water

This is a significant suggestion, because so-called super-earths are one of the most common types of exoplanet found to date: New Worlds Atlas | The Search for Life – Exoplanet Exploration: Planets Beyond our Solar System

And of course, where there's water, there's the potential for life as we know it. Speaking of which...

3. Earliest confirmed life on Earth

When did life begin on Earth? It's one of the trickiest questions to answer, because the earliest forms were almost certainly single-celled forms that don't produce clear fossils.

While a number of possibilities have been suggested, a recent chemical analysis of a sample dating from 3.4 billion years ago shows that chemical signatures in the fossils are comparable with modern bacteria: Microfossils, possibly world's oldest, had biological characteristics

If the results are confirmed, this would be the earliest evidence of life on Earth to date.

4. Milky Way surrounded by ancient galaxies

A recent study suggests that some of the smaller galaxies orbiting our Milky Way may actually be ancient - and date from the beginning of galaxy formation in the universe: Earliest galaxies found 'on our cosmic doorstep'

So we're not alone in the universe - at least in galactic terms - our grandparents are still around. :)

5. Other star systems may become easier to spot

Our solar system is believed to be surrounded by a vast sphere of icy debris - the Oort Cloud. Now a group of researchers believe that existing data from microwave studies could reveal Oort Clouds around other stars: Oort clouds around other stars should be visible in the cosmic microwave background

The problem, though, is that the existence of our Oort Cloud remains just a theory - but any closer examination of other stars can hardly be a bad thing, and likely to lead to interesting surprises. :)

Al Jackson

Well-Known Member
Jul 28, 2018
The population of long period comets is proof of the Oort Cloud. This has been known for a long time.


Apr 24, 2018
Given that hydrogen and oxygen are the first and third most abundant elements in the universe, water should be incredibly common. The real question is whether there is enough of all the other building block elements and salts available in or near that water to form life-building compounds. If there aren't, water is mainly going to act as a poison that constantly dissolves compounds before any reactions can get very far, similar to how people can poison themselves by drinking too much fresh water.

It seems like the trick would be to have enough water to serve as the medium of life without having so much that it acts mostly as a solvent. Ice formation would help by increasing the salinity of the remaining liquid water.