This is why its pretty much impossible for us to find intelligent life outside of this planet.

[Eko]

And this is just the age of the earth.

Take into account the age of the universe, the sheer size of it and the amount of times intelligent life is alive and anywhere near where they can communicate with each other let alone meet is near impossible.

[Ocelot II]

1. There isn't very much of it here, either.

[Eko]

2. Best reply ever.

Eko.

[relayerbob]

3. Yep, and why they don't want to let us know they are out there

[Mr.Bill]

4. I'll bet if they are out there, when they fly by Earth,

they lock their doors.

[brooklynite]

5. This has nothing to do with our ability to FIND intelligent life...

...It may suggest the odds are low, but the odds were low anyway because of the immense size of the galaxy and the number of potential planets to check.

And lower still is the ability of that intelligent life to reach us (UFO stories notwithstanding).

[Eko]

9. The immense size, the immense age

and the short amount of time intelligent life will be around. So it has everything to do with our ability to find intelligent life.

[Silent3]

12. The connection to the odds of finding other intelligent life comes in with the possible brevity...

...of intelligent life once it arises. With our single self-example to go by, there's good reason to wonder if other intelligent life might also be self-destructive.

If so, finding other intelligent life means that the signs we'd hope to find might only be brief flickers in deep time, most of those flickers happening either before or after our own possibly very limited opportunity to catch a glimpse.

[keithbvadu2]

6. 2 space aliens looking down on earth.

2 space aliens looking down on earth.
I see the dominant life form has developed space weapons.
Does this mean they are an emerging intelligence?
I don't think so. They have them aimed at themselves.

[Takket]

7. if you like that, you might like this too.........

[Eko]

10. Seen them both, great stuff.

[Dial H For Hero]

8. The universe is just too damn big, given the limitations of lightspeed.

It's my understanding that with current technology, we could detect a planetary civilization similar to our own by its electromagnetic "leakage" at no more than around 100 lightyears.

Let's also assume that that our ability to detect such things increases by a factor of 100. Since such emissions grow weaker in proportion to the square of the distance, we can now detect our neighbors out to a distance of 1,000 lightyears.

A sphere with that radius would comprise a whopping 0.05% of the Milky Way. There would have to be thousands such civilizations in our galaxy for there to be even a decent chance of detecting a single one of them. And that presumes our ability to find them increases by a hundred-fold.

Are we alone in the universe? Almost certainly not. But it's likely we'll never know for sure, one way or the other.

[PSPS]

11. I remember Sagan making this same point

The fact is that, given the incomprehensible age and vastness of the universe plus our own less-than-a-tiny-invisible-flash time presence in it, it is virtually impossible that there would be a developed civilization anywhere else in the universe at the same time. Sure, there may have been a lot of them but, at the same time? No. Sorry.

[Irish_Dem]

13. So if we are really all alone, it is even sadder that we are going extinct.

Between all the violence and global warming, we are going to wipe out the only life which exists in the universe?

[Eko]

14. Possibly.

If more people understood this would it make a difference? Would they try harder? I'd like to think so, but I am not sure. Either way the end is the end, and its only sad if you don't understand that there is always an end regardless. To everything. There is beauty in that also. To the brief flash of humanity, love, loss, joy. A brief flower to bloom if you will excuse my poor attempt at poetic license.

[Irish_Dem]

16. Perhaps this story has played out before.

A violent, ignorant species cannot survive.

[brush]

15. Nice try but that string is not a great way to demonstrate time.

A well done, chart/graphic by a professional cartographer would've been better...and we could study it and it's markers...instead of not really seeing time/space relationship on that string.