How many known planets outside our solar system have an atmosphere necessary to sustain life?
2 Answers
You don't need an atmosphere to sustain life.
Explanation:
Life takes many forms. Liquid water seems more essential to life than an atmosphere, though the presence of liquid water probably implies at least some atmosphere.
Note also that oxygen is essentially toxic to cellular life that lacks mitochondria.
So it is not clear to me what you would be looking for in an "atmosphere necessary to sustain life".
If we are referring to multi-cellular life, then note relatively complex extremophiles living near hydrothermal vents in the deep ocean.
Considering intelligent life, I think we have to be slightly open-minded as to what form it might take, but it is conceivable that it does require the energy given by mitochondria and oxygen and therefore an oxygen rich atmosphere.
The methods now astronomers use to find Exoplanets are not suitable to detect whether there is an atmosphere.
Explanation:
Transit, wobbling.methods only can detect the proximate size And period of orbit.
Many things lives in sea underwater,They do not have atmosphere there./Only detailed ground based observations with very large telescopes can detect the atmosphere and measure temperature.Present method guessing with the distance from Parent star does not work always..
