All living things on Earth depend on upon the sun as its source of energy. Plants contain chlorophyll which uses the energy in sunlight to manufacture food. However, bacteria which live in extreme environments like in hot water springs use chemical energy to make food. Scientists now say that aliens could be using Cosmic rays to manufacture food. Alien life could get energy from cosmic rays to survive much like the microbes in the extreme environments.
Cosmic rays can penetrate deep into the earth and bacteria living deep in the bowels of Earth where there is water could be munching on cosmic rays to survive. Such a situation can occur in Mars also where deep underground where there is the presence of water. Life could be possible on other planets also. One such place where there is water below the surface is Europa, where there is a possibility of life.
Therefore life could be present on rogue planets which are just drifting without orbiting any particular parent star. Green plants on Earth can utilise the energy coming from the sun. Galactic Cosmic Rays are much powerful and have higher energy than any other radiation on Earth. The cosmic rays on striking the atmosphere on earth produce an array of particles which include neutrons, positrons, electrons and the gamma rays which are very dangerous.
Researchers contend that Cosmic Rays have an enormous amount of energy and they are present everywhere. They can even penetrate through the solid surface of planets.
Computer simulation has confirmed that galactic cosmic rays could provide energy to plants and microbes which live underground both on the earth and other planets. This energy flow could extend support to any organism in an alien atmosphere.