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45 votes
Accepted

Could dinosaurs breathe modern air?

There's evidence dinosaurs in general had the same sort of respiratory system that the modern dinosaurs have kept, which is more efficient than the system used by mammals. This is suspected to be part ...
Keith Morrison's user avatar
43 votes

Can a generation ship withstand its own oxygen and daily wear for many thousands of years?

Titanium Immunity to Environmental Attack Architectural titanium's unsurpassed corrosion resistance results from its stable, highly-adherent, protective surface oxide film. Because the metal is ...
Thorne's user avatar
  • 47.3k
35 votes

Is possible to make an "almost-perfectly" sealed ship?

In a word, no. Perfect seals simply do not exist in the real world. Fortunately, neither do perfect ships. Even if you had perfect seals, you wouldn't be able to cruise the skies for all eternity ...
Cort Ammon's user avatar
  • 132k
34 votes

How could an animal have a truly unidirectional respiratory system?

Maybe not too creative. But indisputably effective. The gill. https://en.wikipedia.org/wiki/Fish_gill Water moves one way through the respiratory system in fish. In the mouth and out the gills. ...
Willk's user avatar
  • 305k
30 votes

Could dinosaurs breathe modern air?

To a lazy first approximation, the O2 concentration now is about 70% of what it was back then. To get a similar effective difference in the partial pressure of oxygen, you can go to an altitude of ...
Starfish Prime's user avatar
21 votes

Could a biological creature get oxygen from oxide rocks or by breaking down H2O?

Photosynthesis? https://en.wikipedia.org/wiki/Photosynthesis You may have heard of it. Certainly you are fond of immoderately huffing the oxygen product of photosynthesis. And you, and you. You ...
Willk's user avatar
  • 305k
20 votes
Accepted

Could a biological creature get oxygen from oxide rocks or by breaking down H2O?

The short answer will virtually always be "not without some other source of external energy. In which case you don't need the oxygen either." That said there's one kind of scenario it could ...
Stilez's user avatar
  • 6,875
20 votes

How large would a tree need to be to provide oxygen for 100 people?

A small frame challenge: Scaling up a tree will not provide more oxygen, as, absent some new biochemistry, larger trees tend towards net neutral oxygen production, eventually becoming net oxygen ...
lupe's user avatar
  • 5,557
19 votes

What is the highest concentration of oxygen a human being can reasonably survive?

Alas, I couldn't find exact details of what percentage of O2 would be the limit; The best I could find for details is the chart below. I did, however, find details on what overdosing of oxygen can do....
Atlas the Worldbuilder's user avatar
19 votes
Accepted

How do I make oxygen for a generation ship?

Closed cycle life support systems (CLSS) are the only way to go for prolonged space travel or even space stations and colonies orbiting a Sun. As pointed out, the real problem is making up losses ...
Thucydides's user avatar
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18 votes
Accepted

How Do I Supplement Oxygen Intake?

First of all, the premise is a bit off. Something like 70% of the oxygen generation on Earth is done by plankton in the oceans, so a blight which kills land based plants will be somewhat inconvenient ...
Thucydides's user avatar
  • 97.7k
18 votes
Accepted

What amount of forrest-fire in square km or metric tons, would be necesary to bring oxygen levels below 19.5% that humans require to stay alive?

Let's start with considering the entire mass of the atmosphere: The total mean mass of the atmosphere is $5.1480 \cdot 10^{18} kg$. We know that Oxygen accounts for 21% in volume, and considering ...
L.Dutch's user avatar
  • 291k
18 votes

Can a generation ship withstand its own oxygen and daily wear for many thousands of years?

You need to fundamentally abandon the idea of building a generation ship, and sending it off into deep space. A generation ship needs to be self sustaining, which includes the capability to recycle ...
Whitecold's user avatar
  • 2,678
17 votes

What is the highest concentration of oxygen a human being can reasonably survive?

It depends on the atmospheric pressure. This chart from NASA shows the relationship between O2 concentration, atmospheric pressure, and how comfortable a human will be breathing that atmosphere. You ...
layagyasz's user avatar
  • 171
15 votes

If we put humans on planets with atmospheres different from Earth's atmosphere, but still containing oxygen, would humans be able to breathe?

100% O2 At normal atmospherical pressure (101.325 kPa) if your only gas is O2 you will have a partial pressure of 101.325 kPa of O2... lethal, deadly and painful. Lets talk about consequences! Oxygen ...
Ender Look's user avatar
  • 8,863
15 votes

Can a generation ship withstand its own oxygen and daily wear for many thousands of years?

The key is in the ecosystem you're taking with you. Organic tech. I contend that it's about an integrated system, not just about one aspect of that system. The floor is a Tapestry Lawn: Attribution: ...
Escaped dental patient.'s user avatar
14 votes

How do I make oxygen for a generation ship?

The most common solution to this approach is to try and mirror Earth's biosphere. Since you need water, food, and air, you need a solution that provides all 3. Hydroponics (and its closely-related ...
Kromey's user avatar
  • 8,535
14 votes

Can you have reduced visibility (due to fog) but an atmosphere that is still breathable?

Fog is just a suspension of minute droplets of water/liquid in the atmosphere. If the atmosphere was breathable before the fog, it stays breathable also with the fog. There are cities in our world ...
L.Dutch's user avatar
  • 291k
12 votes

Could a biological creature get oxygen from oxide rocks or by breaking down H2O?

No, you cant use rocks for oxygen for oxidizing organics, like we do, and get energy. However, there is a large set of reaction that can substitute the process that you are interested in. In ...
Surprised Seagull's user avatar
11 votes

How do I make oxygen for a generation ship?

The Ship A generation ship carrying one million people for an indefinite period will need to carry or generate a minimum of 550,000,000 litres of $O_2$ per day. Mixed to match Earth atmosphere ratios, ...
rek's user avatar
  • 13.1k
11 votes

Alternative elements for oxygen transport in an alien blood

Coboglobin is one of the main iron- and copper- free proteins that can be used for oxygen transport. It was first synthesized by humans in 1970, where cobalt was intentionally substituted for iron in ...
HDE 226868's user avatar
  • 101k
11 votes

Metallurgy in the Carboniferous- Just how much hotter are fires?

One of the common misconceptions is that high concentrations of oxygen lead to hotter fires by default; it's actually fairer to say that high concentrations of oxygen lead to faster fires by default, ...
Tim B   II's user avatar
  • 54.1k
11 votes
Accepted

How high a mountain could possibly be climbed?

TL;DR: 12-15km Earth-equivalent altitude, because you start needing spacesuits and pressurized habitats instead of a nice warm coat and a tent. You might be OK if you could launch rockets to drop ...
Starfish Prime's user avatar
11 votes

Would copper-based blood be more effective at carrying oxygen rather than iron-based? Or would it hinder the delivery of oxygen?

would it be worse than iron-based blood Yes, as NixonCranium's answer states. Haemoglobin is a more efficient carrier of oxygen, so for equal concentrations of oxygenating compounds in the blood, ...
Graham's user avatar
  • 20.9k
10 votes

What can I add to an oxygen/nitrogen atmosphere to make it unpalatable or poisonous to humans, yet stable and breathable to local creatures?

Carbon Dioxide The simplest and most straightforward solution. Deadly to humans at concentrations of around 10% (this is on the high end of 'a few percent by mass' but you said you will take what ...
kingledion's user avatar
  • 85.5k
10 votes

Can a generation ship withstand its own oxygen and daily wear for many thousands of years?

Is there is any material for an engineered structure or set of systems that will resist oxidation for the many thousands of years required for the journey? Aluminum, when in contact with oxygen, ...
L.Dutch's user avatar
  • 291k
10 votes

Archipelago worlds build up atmospheric oxygen faster?

No There are a lot of issues with that assumption, but I'll go through it all as concisely as I can. Oxygen isn't the only limiting factor to arthropod size Arthropods are exoskeletal by definition. ...
Tim B   II's user avatar
  • 54.1k
9 votes

What can I add to an oxygen/nitrogen atmosphere to make it unpalatable or poisonous to humans, yet stable and breathable to local creatures?

Nitrogen dioxide. http://emedicine.medscape.com/article/302133-overview From http://www.healthhype.com/silo-fillers-disease.html Nitrogen dioxide damages the lower airways in particular and the ...
Willk's user avatar
  • 305k
9 votes

Is possible to make an "almost-perfectly" sealed ship?

After reading Cort's impressive answer; I'd offer an alternative, to "nearly" perfectly sealed. Construct a cover that fits over the ship; as close as possible with the constraint of being only two ...
Amadeus's user avatar
  • 34.7k

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