Astronomers agree that there are trillions, maybe quadrillions of stars. They further agree that many of these stars have planets circling them. Billions of these planets enjoy conditions capable of sustaining life as we know it (These are called “Goldilocks” planets).
Probability suggests that at least some of these may, in fact contain life. After all, there’s some form of life almost everywhere on earth no matter how harsh the conditions, from the ice in Antarctica to the deepest trenches of the oceans.