Planets In The Habitable Zone

mistah_monkey writes: "The BBC reports that an international team of scientists have identified some planets in what they call the habitable zone. Apparently, the planets may be as big as Jupiter, but exist in a region surrounding the stars they orbit in which water can exist as a liquid, which is good news for those of us who believe that little green men might actually be out there somewhere."

Comments

Life in Pressure Cookers

[twisty]

There are holes in this 'zone'... Those familiar with the physics of Chemistry know that water has a triple-point: south of this point, the pressure is so light that there is no liquid water... it 'camphors' or evaporates straight from solid to gas. North of that triple-point, the increasing pressure broadens the range of liquid water, as the temperatures of melting-point and boiling-point move further apart.

So let's go back to the notion that we're not talking about extraordinary life, thriving under pressure. Let's talk worlds we can personally colonize. We really aught to be seeking small planets like ourown, but dense ones:

Earth is the most dense planet of our system. Just divide Mass by Volume, and the greatest mean density is our own. Saturn has hte least, which may account for its lovely rings. But there are many fine balancing points working in Earth's favor:

• High Density==needed pressure for liquid water.
• Small Size==low gravitational mass, ==fewer sheering stresses fighting life's 'order.'
• Proximity to Sun==dynamic energy ('chaos') for creating (mixing) and sustaining (maintaining) life.
• Distance from the Sun==cooler order to prevent life from burning away in excessive energy.

So earth is unique to our system in being a light-weigth pressure cooker for life. We actually have a better chance outside our own solar system, where greater planetary densities exist, if getting there can be trivialized. Then again, the technology to make insterstellar travel trivial would likely make terraforming even more trivial.

From a Jovian's point-of-view

[Trinition]

I don't see how a planet such as Earth could have life. Its gravity is so weak, due to its small mass it could only capture *one* moon! With such low gravity, the gaeous pressure is so low that no organism could possibly find enough nutrients at that density to sustain its life.

Furthermore, even if it could, its body would surely explode due to the low atmospheric pressure. Or, perhaps the weight of the organism could not be suspended by the atmospheric pressure and it would crash to the center of the planet.

There is also the thin atmosphere. The planet is small enough, but its atmosphere is a tiny shell and hasd a relatively massive solid core. That leaves little room for life to develop.

I tell you, Earth is no more habitable to life than Mars is now ever since the Matrians turned their gas giant into a desolate rock!

Re:Link to paper

[Cyclopatra]

I was poking around looking for something with an intended audience somewhere between the BBC article and the paper. No real luck, but here's the full story from the Anglo-Australian Observatory website; it's got some figures and vital statistics on the planets, as well.

-Cyclopatra