In general, yes. In the expanse of space there must be life somewhere.

For fun I let myself believe they've visited earth, and that at least some UFOs were alien, but that's more of a fun "what if..." belief than anything and it doesn't impact anything beyond my imagination.

Yes. The older I get, the more I believe it is actually a Men in Black kind of situation.

I definitely believe that aliens exist, but I very much doubt that they have any interest in contacting us. I find that lot of the discussions around aliens fail to take into account the sheer vastness of the Universe.

• Universe has been around for close to 14 billion years
• Milky Way in its current form has been around for about 8~9 billion years
• Life on Earth appears around 4280 million years ago
• Humans start evolving around 2.8 million years ago.
• Use of language appears around 100,000 years ago
• Writing is invented around 5500 years ago

Inventions of language and writing are the landmark moment here. Before language was invented the only way information could be passed down from ancestors to offspring was via mutations in our DNA. If an individual learned some new idea it would be lost with them when they died. Language allowed humans to communicate ideas to future generations and start accumulating knowledge beyond what a single individual could hold in their head. Writing made this process even more efficient.

So, after millions of years of life on Earth nothing interesting happened. Then when language was invented humans started creating technology, and in a blink of an eye on cosmological scale we went from living in caves to visiting space in our rocket ships. It's worth taking a moment to really appreciate just how fast our technology evolved once we were able to start accumulating knowledge using language and writing.

Now let's take a look at how technology itself has been evolving. Once we discovered radio communication we went through a noisy period where we were leaking a lot of our broadcasts into space, and within a span of a 100 years we started using more efficient communication, and encryption. If somebody intercepted our broadcasts today they would look like noise because they're designed to look like noise.

Our society today is utterly and completely unrecognizable to somebody from even a 100 years ago. If we don't go extinct, I imagine that in another thousand years future humans will be completely alien to us as well.

So the period during which intelligent life would be recognizable to us during its course of evolution is infinitesimally small! The time between creating language and becoming an advanced technological society is measured in thousands of years, while evolution of life is measured in millions of years. The chance of two different intelligences finding each other at exact same stage of development where they might be able to communicate is incredibly unlikely.

I would also imagine that the biological phase for intelligent life is rather short. We're likely to develop human style AIs within a century, and they will be the ones to go out and explore the universe. Meat did not evolve to live in space because we're adapted to gravity wells. An artificial life form could be engineered to thrive in space without ever needing to visit planets. This is the kind of life that's most likely to be prolific in space.

Furthermore, post biological intelligences would likely be running at much faster speeds than our mental processes operate on. What we consider real-time would be what we consider to be geological scales.

For all we know the Universe may be teeming with intelligent life and we just don't recognize it as such. We might be like an ant hill next to a highway looking to see if there are other ant hills around.

I really can't imagine that advanced civilizations would have much they could learn from us. We might be a curiosity at best to them, but it's more likely that they would give as much consideration to us as we do to an ant when we pass it by.

Yes, and I think, potentially, that it could be so advanced that we don't have the ability to recognize some or all of them.

As other people have said we cannot for of they do our do not exist.

That said thinking about how big the universe is, my personal opinion is they have to exist.

As for governments covering them up.... highly unlikely. They can't even cover up their dirty laundry, let alone aliens

Yep. Not in the crazy conspiracy theorist kind of way, but considering that the universe is so small, it feels pretty hard to believe that there isn't anyone else out there.

I do! Perhaps alien life could even be hiding in plain sight on Earth, and someday we will discover a virus or a bacteria that looks nothing like anything else on Earth and could've hitched a ride on a meteorite!

Sure. Immigrants have that can-do attitude that makes them much more likely to become entrepreneurs and small-business owners. I've worked for several.

Has intelligent life that we could communicate with ever existed in time? Yes. Does it exist in this exact moment? Unlikely. Is it or is it ever been in a proximity that we could communicate? No.

That’s not to say there isn’t intelligent life that we cannot understand or communicate with. If we exist inside the brain of some universally large creature, and our existence is just luck, we won’t ever be able to communicate.

I have something new to say about this. Hold on.

Capital A Aliens, all the conspiracy theory stuff? No, absolutely not. I think the people of the future will see that exactly the way we see demons, angels, djinn, all the stuff people used to believe in. It's a religious belief not science, no matter the pseudoscientific jargon it's wrapped in.

Aliens somewhere out in the universe? Yes I believe there are more planets with life, out there.

And I also believe there is Something - whatever the force is, that people used to call demons and now call Aliens, I do think it's something, I just think that people convinced it's aliens are as wrong as the people who were convinced it was whatever else in the past.

I would believe in alternate realities overlapping ours before I would believe in living organic beings traversing the vastness of space to get here, then hiding and yet talking to governments or individuals somehow at the same time.

I'm open to the idea of life outside of Earth, but I'm sceptical that governments can keep them secret when they can't keep sex scandals, drug use or financial crimes by leaders secret.

Growing up in a devout Muslim society, I was made to believe that aliens don't exist.

But I simply thought that this couldn't really be possible since there's at least a few other planets that have signs of life, surely there's a civilization in there, even if it's as smart as the animals on earth.

It's possible they're out there but it doesn't change my life at all one bit. My take-away is that hopefully I live long enough to get to see them for myself if they're out there, out of sheer curiosity for how intelligence could evolve from unknown circumstances.

As a metaphysical solipsist, I haven’t decided yet.

I’m sure there is intelligent life out there but if we ever cross paths is very uncertain.

Carl Sagan was the Neil deGrasse Tyson of his day. No contributions to science other than self-popularization.

Yet he left this lingering idea that because the universe is immense the unique preconditions required for life would necessarily appear many times. Many people assume this is a "scientific" position and just rattle it off like a pull-string toy.