Back in this solar system, Venus has an atmosphere rich in carbon dioxide, causing its surface temperature to be over 460 °C.

Not ideal for life as we know it...

Welcome our tremendously strong superbeing overlords?

Welcome our Gravity enriched super overlords. (Sorry)

Said oxygen was also produced by the same original life forms ("oxidized" from the reduced form where oxygen naturally occurs, e.g. in CO2 and H2O), hence the significance as an indicator of life.

Is the Huble telescope actually an implimentation of Professor farnsworth's Smeloscope?

If their method relies on detecting near-infrared emissions of the planet's super-hot atmosphere, presumably it won't therefore work on a planet that doesn't have a super-hot atmosphere. One that would be more likely to support life, for instance?

That planet is just like southern Spain.

Hot, smelly and full of aliens!

Let's face it: we know only about EARTH life. For all we know, that planet houses uberbig ammonia jellyfish who have recently invented a jetpack that can fly for FORTY seconds.