Earth-Like Pre-Photosynthetic Planets

[SaxonViolence]

Friends,

 

I hear tell that once the Earth's atmosphere was largely Methane, CO₂ and Nitrogen, of course.

 

Then green plants broke down the CO₂. The free O₂ burned all the methane to make water and CO₂ and some other water soluble substances got washed out by the rain.

 

I've also heard it proposed that if we ever encounter such a world, we should seed it with some algae and it will have an Earth-like Atmosphere in about 50 000 years.

 

What I'm wanting to know—just how hostile an environment was the old Methane Atmosphered Earth?

 

What would have been the Temperature/Air Pressure on the surface?

 

How rainy would it have been?

 

Storms? Hurricanes? Tornados?

 

Could you have walked on the surface with a simple Oxygen mask?

 

Need eye protection?

 

How about the skin?

 

Would the primitive atmosphere have been corrosive to the skin?

 

Is it conceivable that folks might decide to live there?

 

I mean there would be plenty of water, carbon even hydrogen.

 

Sure you'd have to live under a dome, but you'd have gravity—which can be a plus—and good radiation screening.

 

People with their feet on the ground just might be able to cultivate land plants—as opposed to simple algae—and speed up the transformation.

 

So how feasible are "Early Bird"—by about 50 000 years—Colonies?

 

 

Saxon Violence

Edited October 12, 2013 by SaxonViolence

[moonguy]

Methane is not corrosive on human skin. LIQUID Methane is a no-no on human skin, but that is not at issue here.

Human lungs cannot convert Methane into anything useful. Alveoli in the lungs require a very narrow range of pressure and humidity so the question of whether humans could operate with just an O2 mask is dependent on that. My guess is 'No' because Methane can saturate human tissue to toxic levels. I have something in my files about all this and will dig up the figures if you need. For now, I recall at least one source that indicated Earth's atmospheric pressure was somewhere between 1/2 to 2/3 what is now. There are other sources with different estimates.

 

Storms? Tornadoes? Hurricanes? Definitely. This is not particularly dependent on chemical content of 'air' but energy balance (or lack thereof) between solar heating and cooling. A Methane atmosphere would definitely have a different cooling rate from the current atmosphere but at this distance from the Sun - and the extent to which volcanic dust was present in the air -its likely Earth was much warmer than now.

 

People might want to live anywhere. There was a TV show, 'Terra Nova', about a group of people who chose to live on an earlier Earth - with dinosaurs. Go figure. Said TV show is available on Netflix.

 

A colony's feasibility is really about the ability of inhabitants to understand and deal with challenges from an environment and the extent to which they are equipped to. So I'm thinking 'Yes', an early Earth colony could be feasible.

 

Perhaps the earlier Earth was where Isaac Asimov's 'Founding Fathers' landed - not realizing they had broken the time barrier.