Originally Posted by Johny Traffic

No

Aliens almost certainly exist. The universe is just too vast for other life forms not to exist. Or have existed, or will exist, whether that is life as we know it or life not as we know it.

The fact that their could be or could have been life as close as our own solar system (let alone life not as we know it) makes it an almost impossibility that their isn't life.

I would say anyone who has any idea at all on just how big the universe is could not deny their is life out there.

But

if you are asking, do I think that people who look exactly like us (but green) with two arms and two legs are driving zillions and zillions of miles in space ships that look conveniently like we envisaged them in sci fi movies.... and have arrived just at the one brief moment in time that humans are alive on our planet and that is the explanation for someone seeing (or not) a big shiny round thing in the sky.

Then no.