We humans represent a minuscule portion of one galaxy in a universe comprising an uncountable number of galaxies. Our solar system is in turn a tiny spec a pin-prick of light glowing in the vastness of our own relatively small galaxy yet we cannot manage to travel beyond our own natural satellite, the moon. Sure, we have sent probes and cameras to the outer edge of the solar system and beyond but these journeys take many years and reap valuable yet still arguably indeterminable results.
Beyond our solar system lie countless billions of stars in this galaxy alone around which planets and satellites orbit in exotic but unreachable solar systems. We know they are there, long range imagery show us many things far beyond our reach yet they still remain points of light in a boundless galaxy full of stars.
Many people suggest evidence exists that prove this planet is frequently visited by aliens, and throughout history we can find drawings, sketches and curious artefacts and even structures that defy our efforts to fathom their origin or construction. The great pyramids represent an engineering feat still far greater than contemporary human construction skills yet they stand as mute evidence that some form of civilisation existed that possessed means and skill required to construct such monuments that have withstood thousands of years.
To suggest given the evidence that surrounds us, and the vastness of our own galaxy that humans and this very planet are the only possible places where life can exist is clearly an absurdity. Even on our own planet, we are still discovering new forms of life existing in environments that were previously considered as impossible in terms of supporting any life form. An undersea volcanically active area near the Hawaiian Islands continuously bubbles at temperatures far above the boiling point of water and at considerable depth below the ocean surface. Gasses and chemical emissions from numerous places create a sulphurous acidic environment at this great temperature yet recently a form of coral was discovered growing around rocks very close to the bubbling lava.
In space, we have been attempting to communicate with extraterrestrial life for many years. The fact remains that, publicly anyway we are still to be answered. Perhaps an answer has been sent many times over but we are unable to see or hear it, who knows? Too many questions remain unanswered yet in my opinion, too much evidence exists all around us to believe anything other than the fact there is life everywhere in our own galaxy. The fact we cannot see or communicate with it is irrelevant, perhaps in time we may discover a means to do so however denial seems pointless.