Could there be lifeforms at the outer edge of our solar system?

 Could there be lifeforms at the outer edge of our solar system?

"An artistic representation of how the northern infrared aurora would have looked in 2006 (marked in red). The darker red locations indicate confirmed aurora locations, with fainter red used to mark possible aurora locations. Credit to NASA, ESA and M. Showalter (SETI Institute) for the background image of Uranus, as was observed by the Hubble Space Telescope (in the visible spectrum) in August 2005. Credit: NASA, ESA and M. Showalter (SETI Institute) for the background image of Uranus, as was observed by the Hubble Space Telescope (in the visible spectrum) in August 2005." (ScitechDaily.com/Discovering Uranus’ Glow: New Hints for Life on Icy Exoplanets)

The researchers at the Leicester University confirm the IR-aurora around Uranus. That IR aurora could give energy to theoretical lifeforms, that can live on Uranu's high atmosphere. 

Could there be lifeforms on super-gold worlds like Uranus? Life as we know it requires liquid water. And the temperature on those icy worlds is very low. But then we must realize that things like gas pressure and gravity also affect water's melting point. If the gas pressure is almost zero, water could be liquid at very low temperatures. There could be lifeforms in Uranus' atmosphere or on the Triton moon. The metabolism of those lifeforms will be extremely low.

Global Color Mosaic of Triton, taken by Voyager 2 in 1989 (Wikipedia, Triton)

But because Uranus turns its other pole to the sun, there is a possibility that in that planet's higher atmosphere are primitive algae or bacteria that use the weak sunlight for photosynthesis. Even the atmosphere at high altitudes on the Uranus and Triton moons is very thin. It would not give protection against solar wind; we must realize that solar wind is very weak at the outer edge of our solar system.

Pluto

If we think of the dark smokers or cryovolcanoes on Triton Moon, the black smoke is nitrogen, ammonia, methane, carbon dioxide, and/or carbon monoxide. Carbon dioxide and methane are organic gases that are forming on Earth because of biological processes. 

The reason those cryovolcanoes exist is their low gravity and low gas pressure. There is a possibility that there are some kinds of lifeforms on Triton and Pluto. There is a possibility that those hypothetical lifeforms can get their energy from volcanic temperatures and weak sunlight. If those lifeforms existed, those creatures would be very slow and long-lived. Their metabolism will be extremely slow.

https://en.wikipedia.org/wiki/Cryovolcano

https://en.wikipedia.org/wiki/Pluto

https://en.wikipedia.org/wiki/Triton_(moon)