Could higher land-based life exist on a planet with a pressure of about 1 MPa?
This is somewhat of a follow-up question to my ammonia-based world question. I've found out that the melting point of ammonia is at 25°C at a pressure of about 1 MPa (about 10 times the atmospheric pressure on earth). I think that should be definitely warm enough for life. However, could higher land-based life actually exist on a planet with such high pressure, especially considering the higher gravitation that would be needed to create such a high pressure?
1 answer
Plausibility
To answer your implied question about the possibility of this high pressure: Jupiter's surface has a pressure of 100 times the Earth's. Cosmically, pressures this high are trivial: think of "small" cosmic bodies like the Sun, which has a pressure around 50 times that of Jupiter. Scaled up, the pressures become unimaginably high.
Life
Human bone has a compressive strength of around 170 MPa, meaning it would still be able to hold the human frame up at 1 MPa pressure. However, human body temperature is 37 degrees Celsius. High or low ambient temperatures can cause hyperthermia or hypothermia respectively, the former more lethal faster (hyperthermia can kill at 42C, compared to hypothermia at 27C). Pressure increases temperature, so a planet with a higher pressure would initially at least have a higher temperature and a higher chance of causing hyperthermia. The planet could cool down when the pressure stabilises though, making it once again suitable for life, and of course planets further away from their stars are cooler.
Summary
It depends. If the ambient conditions are right, life could survive such a planet. But, it would need the prerequisites for life, such as water, and the current perception is that any habitable planet must be in the Goldilocks zone of its star.
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