What do you think is the best explanation to the Fermi paradox?

Question

What do you think is the best explanation to the Fermi paradox?

Answer 1

Good question.  I've thought about this for years and have nothing really satisfactory to say.  It does seem to me that we're only a century or so away from being able to build robot starships that will self-replicate and take over the Galaxy.

A couple possibilities:

1) The Drake equation terms are all a bit smaller than you might think.

2) The Earth has been made into some sort of aboriginal reservation.

3) There is some absurdly simple and extremely dangerous technology that we haven't quite discovered yet, something that, e.g. would allow an 8-year-old boy to make a black hole.

4) Intelligence is much weirder than we think.

5) There is some philosophical or technological discovery we haven't quite made yet, that makes galactic colonization pointless---for example, once your computers are good enough, everyone drops into a virtual space and feels no need to ever come out.

Answer 2

distance.

The universe in general is not a friendly place.  It is possible that life evolved to this stage on Earth because we were left alone (by nasty radiation spewing events, I mean).

We live far enough from the core of the Galaxy to avoid any sporadic X-rays and gamma rays from matter falling into the black hole.  We live in or very near the "local bubble", an area blown empty by a supernova a million years ago.

We have had no recent hypernova from pole-on stars (when a very big, rotating star goes supernova, a lot of nasty radiation is emitted, a lot of it goes out in the direction of its poles).

Even though there are probably lots of other planets out there, not all of them would have had this chance (and the chance has to hold for a good portion of a million years or so).

That would explain why there could be very few civilizations per galaxy.  Therefore, the distance between each civilization would be very large (thousands of light-years).

Answer 3

I'm not sure it needs an explanation.  Just because we haven't made contact yet, doesn't mean we won't, next week, next month, next year or whenever.  Given the sheer size of the Universe, it is hardly surprising we haven't heard from anyone yet.  Maybe "they" just haven't got round to us yet!

Answer 4

Obviously we're the only show in town and if some show up (especially just in time for 2012), I'd be more inclined to see them as really being 'fallen ones'.

Answer 5

simply the size of the universe and the scarcity of civilizations that have already attained a spacefaring civilization

Answer 6

It is very difficult to travel from one star to another. Once there, they'd have to terraform some planet to make it livable. Civilizations will only do it if they have to.  They only have to when their parent star becomes uninhabitable.  Stars, like the Sun, haven't had time to become uninhabitable given the age of the Universe.  So, there's no paradox.  We haven't seen them arrive because they haven't left home.

There are lots of other answers.  This just happens to be my current favorite.

Answer 7

It's only a paradox if you (wrongly) believe that we have the capability to detect intelligent life in the universe. In fact, we have no such capability. None whatsoever. SETI is mere whistling in the dark. It's not EVEN whistling in the dark. The reality is that even if they were there, chattering away at each other with magnetrons the size of planets, we still would not be able to detect them. Even if there were von Neumann devices mining the asteroid belt, we probably would not detect them.

The only way we ever would have even the slightest possibility of detecting alien intelligences would be if they were making a positive effort to communicate with us personally using a directed method, such as a tightly beamed transmission or popping down to Earth for a visit, and who in their right minds would want to talk to *us*?