Where to Find Alien Life

One of the reasons life survives on Earth is that we have a big brother protecting us from sterilizing events (asteroid bombardment).   Jupiter has been a powerful sink for asteroids that would have killed us all.  To find alien life in another system we should focus on those systems which have a large planet well outside the habitable zone as seen here. Exoplanets.org has a list of known exoplanets, and it is sortable by the semi-major axis.  Click on that column to sort the exoplanets by their distance from the primary.

Jupiter is about 5 astronomical units (AU) from our G-type star.  Here are the first 4 likely candidates.

590 light years away near Pavo is HD 190984 , an F8 star with a big planet at 6 AU.

40 ly away is 55 Cancer, a G8 star with a big one at 5.9 AU.

At 85 ly in Libra, HD 134987 is a G8 star with a planet 0.8 Jupiter masses at 5.8 AU.

49ly away mu-Ara is a G3 star with a planet twice the mass of Jupiter at 5.3 AU.

Statistically speaking these are outstanding targets for hosting alien life.  A more detailed analysis may preclude one or more of these due to orbital eccentricity, other planets, or binary star systems.  But if spontaneous generation of life is common then at least one of these systems hosts alien life.

Too cold for life

Speculation about life on Titan or other cold worlds is misguided because the chemical reaction rates are simply too slow. All chemical reactions have a rate.  That rate has an exponential dependence on temperature as described by the Arrhenius equation.

rate = A exp (-Ea/kT)

Ea is the activation energy, k is Boltzmann's constant, T is the temperature, A is the pre-exponential factor

Chemical activation energies are best measured in electron-volts or eV.  Typical values are between 1 and 3 eV, usually closer to 2.0.  The ground temperature on Titan is around 94 oK or -179 oC.

Thus a chemical reaction on Titan would be roughly 73 orders of magnitude slower than the same reaction on Earth (298 oK).  So a reaction which takes a microsecond on Earth would require 10^60 years on Titan. (That's 1000000000000000000000000000000000000000000000000000000000000 years).

Pre-exponential factors for chemical reactions have a certain value which represents steric  effects.  They cannot be 60 orders of magnitude larger because molecular geometry is not that pliable.

Traditional chemical reaction based life is impossible on Titan or any other location where the temperature is so far below 298 oK.