By the sheer amount fo galaxies existing, alien life is gauranteed to exist due to the fact that if the right conditions are met life becomes endemic to the planet, and those conditions are not impossibly hard to achieve.
But by the expansion of the universe combined with the forces of gravity basically separating the universe into random dots composed of several galaxies who will eventually become one, alien life is guaranteed to exist beyond any concievable distance that can be travelled by man.
To give you an idea: beyond andromeda, all other galaxies move faster than any communication we can have with them. We can't send nothing towards them because by the time they'd even leave our galaxy everything else would be so far away we won't even be able see it.
Now, why doens't life exist within our own galaxy, is ultimately a matter of luck and the fact that we have no viable way to send humans off planet without taking millenia to get any considerable distance within the galaxy. Perhaps one day we will find a distant radio communication from an alien planet, but that wuld be it. We'd have no way to reach them.
Anthony Reyes
The speed of light is big
Cameron Torres
>why is there no physical evidence floating in space what do you think the moon is
Jackson Bailey
> It would only take about 200,000 years for self-replicating probes to visit every star in the Milky Way
The milky way is 100,000 light years wide. So to even travel across in 200,000 years would require traveling at 0.5c.
Just doing some math on my own, getting 70kg to 0.5c would take about 40% of the worlds global energy output. If you double that, since it will have to slow down as well, you are talking about a probe that can not only complicated enough to replicate, but also able to generate immense amounts of power.
Makes no sense senpai.
Ryan Moore
I got the 200,000 figure from a white paper from the Future of Humanity Institute. I dont remember how they came to that number, but you can probably find out with a Google search.
William Peterson
I think that's based on a calculation once done by Carl Sagan, but I have trouble finding a direct quote. Is that using conventional chemical thrusters?
Although said probes would've come and gone unnoticed, the entire purpose of a probe being an small efficient low-mass instrument.
I'm not sold on Dyson spheres. Just because it's the application of power consumption taken to its logical extreme doesn't necessarily mean it's actually necessary, vital, or desirable to build one even for an extremely advanced and super power-hungry alien civilization. Not to say it wouldn't exist, but would it be prevalent enough that we would be able to see it using current telescopes? >why doens't life exist within our own galaxy bait?
Oliver Gutierrez
>tfw fellow hyper-futurist
Exactly. A civilization only exists within this universe long enough to discover this ability, then disappears into its own seemingly invisible universe.
I was a big fan of the Tipler/Kurzweil "envelope the entire universe with computronium" approach to highly advanced civilizations, until it occurred to me that there's a quicker way, hinted at in Arthur C. Clarke's novelizations of 2001: A Space Odyssey and 2010: Odyssey Two.
Noah Foster
Maybe they forgot a 0
Caleb Fisher
The most effective search for life right now would focus on stars. A randomly blinking and dimming star, or one with a completely inexplicable chemical makeup would be good ways to signal occupied systems, and we've found one example of both of those.
