The range of galaxies is between several hundred billion to potentially as many as 20 trillion. Our galaxy has between 100 billion and 400 billion stars and isn't atypical. In other words, if we're 1 in a billion (and we're not) then our galaxy has 100-400 other civilizations. Now expand that across another hundreds of billions or tens of trillions of galaxies and yeah, we're not alone.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913414)

It is simply a numbers game.

The range of galaxies is between several hundred billion to potentially as many as 20 trillion. Our galaxy has between 100 billion and 400 billion stars and isn't atypical. In other words, if we're 1 in a billion (and we're not) then our galaxy has 100-400 other civilizations. Now expand that across another hundreds of billions or tens of trillions of galaxies and yeah, we're not alone.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913436)

Lastly, where are they?

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913450)

Can we cross the unfathomable space? No? Then it is totally realistic that there are tons of civilizations that are like us and also can't cross the unfathomable space. If you look at where we are in the galaxy and realize that humans haven't even left our solar system or explored the solar systems near us let alone our portion of the galaxy let alone the entire galaxy let alone cross to the nearest galaxy away from us let alone our cluster of galaxies and so on.

Finally, you assume 2 more things: 1. that even if they can contact us that they would want to, and 2. that they haven't been here.

Another thing to consider that even for humanity's civilization, assuming we want to communicate with other civilizations across the stars we've had the ability to do that for 50ish years or so. Even with that our means of doing so are extremely primitive - it isn't clear that it is realistic across the stars. Radio transmission is very slow and we're talking about a huge number of light years, meaning that even if we somehow found a way of transmitting communications at the speed of light, assuming we sent something 50 years ago we would be limited to distances of 25 light years away assuming the civilization immediately responded with something equally fast. 25 light years is nothing.

tl;dr - the "unfathomable distances" is the problem.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913598)

See Dark Forest Theory.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913448)

Will we ever get in contact with them, unlikely

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48913529)

The number of opportunities and the time scale for life to arise seem to me to be such that it is extremely unlikely there is no more life around, especially when we find so many organic precursors floating around everywhere we look. Whatever the life creating process is, some parts of it look pretty common. We also know that evolution works, so if there is life it's going to evolve, and some number of those evolutions will result in technologically capable intelligent life as well as some things we can't even imagine. My bet is that there is plenty of thinking life around. However, that doesn't mean we'll ever meet it.

It's a long way between stars. If we lived in a more densely packed region of space we might hear radio or detect industrial signatures. That still could happen as detection improves.

Also, as noted, in order to contact another group you have to coincide both in space and in time. It may be that the time window within which most life forms have to do any contacting could be brief for various reasons.

Travel is tough. In the absence of warp drive it takes huge amounts of time to go exploring, even assuming you can muster the resources. Only very long lived critters could do it unless their physiologies are amenable to some kind of long term hibernation. Machines are more likely to do the exploring. Without inventing anything magical you could imagine doing it with machines up to tens of light years away, provided you are able to wait thousands of years for the results. The bargain way to do it would be with small vessels filled with explorer nanobots. Musk's guys could probably get this done within a few decades from now. BTW the nanobots could be mechanical or biological, or some combo.

There could be aliens living in more populated parts of the cosmos who bump into each other often. There could be solar systems in which intelligent life has evolved on more than one world at roughly the same time, and they can have a jolly time trading, raping, pillaging, nuking each other, etc. At the very least they could swap TV shows.

The same could happen in denser parts of space. In our neighborhood star density is about .004 stars/cubic light year. The galactic core is about 1600 stars/cubic light year. The core is a harsher environment for life, but note that the density range is a factor of 400,000. There probably are better interstellar urban neighborhoods for meeting the neighbors than where we live in the boonies, though the core may be a little too busy.

Schrödinger's alien is both there and not there. One observation will resolve the issue.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48915009)

Without the occasional genius being born, humanity would still be very primitive, if not extinct. Maybe lots of aliens achieve language, tool use, etc, but just don't have anyone that can discover calculus.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48925061)

My take is really that even if the galaxy is teeming with intelligent life, those beings might still lack our ingenuity. If so, we're alone in the sense that we'll never find them and they'll never find us.

(http://www.autoadmit.com/thread.php?thread_id=5721781&forum_id=2#48925200)