43

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 of the reason why they could get to such a huge size; they could more efficiently process it to extract the oxygen, and there's no reason to assume they'd have ...


31

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 about 2900m. Without acclimatization, this can be quite unpleasant (or potentially life threatening) and physical activity can be challenging. It is possible to ...


7

I think the trees can be as tall as you'd like, but they'll start to look pretty different from Earth trees. I spent quite some time developing a world that sounds a lot like what you're working with and have since then taken chunks of that setting and made it more extreme for roleplaying game environments. Here's some of the stuff I did before I added any ...


7

The Cretaceous period was long. There were periods when oxygen was 30% and there were periods (after massive volcanic eruptions) when there were 18%. I can't say it had no effect on the biosphere, but dinosaurs (and T-rex especially) kept their apex positions in both cases. But these changes were slow, taking place over the course of generations. So these ...


5

Your planet is kicking out huge quantities of radon gas. https://en.wikipedia.org/wiki/Radon Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through which thorium ...


3

There are a number of issues to overcome with giant trees. The first is the force of the wind. Any storms will have a disproportionately larger effect on taller trees. This might be aided by a less dense atmosphere. Additionally if the day length was longer than on Earth it might help as one of the major drivers for storms is the difference in atmospheric ...


2

Firstly, you would need to define 'circulation cells'. If you're talking about, say, low pressure surface systems, these are considered 'synoptic scale', and tend to be on the order of 1000km+ of horizontal distance. These surface lows circle Antarctica, for instance, riding the upper atmospheric river of air known as the jet stream. As wind exits troughs ...


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