Science buff- Like Barack Obama? Better not like manned spaceflight then

[DinoDoc]

Originally posted by Kuciwalker
Any civilization could colonize the galaxy in ~3 million years - almost no time.

Based on?

[Kuciwalker]

Rough consensus of a bunch of back-of-the-envelope estimates.

[DinoDoc]

Based on?

[Kuciwalker]

Speed of light, size of the galaxy, guesses as to how long it would take a new colony to develop enough to send off its own colony ships, stuff like that.

[Geronimo]

Originally posted by Kuciwalker
Unless all highly-advanced civilizations "go dark", we should be able to pick up signals from [sufficiently advanced] civilizations even in other galaxies.

is it so far fetched that they would all go dark? there doesn't seem to be much incentive to use recognizably artificial radio signals for long after you go digital.

[Whoha]

Originally posted by DinoDoc
Based on?

The milkyway is 75,000 LY across. At 10% of the speed of light that is 750,000 years to cross.

Assuming we can build ships that can survive, that can travel at .1c,that can eventually reproduce themselves,and seed an area with Humans then we could do it in the blink of a cosmic eye.

[Kuciwalker]

Originally posted by Geronimo
is it so far fetched that they would all go dark? there doesn't seem to be much incentive to use recognizably artificial radio signals for long after you go digital.

\

At some point the raw energy output of a civilization [think dyson-sphere level] becomes detectable.

[Whoha]

Originally posted by Geronimo


is it so far fetched that they would all go dark? there doesn't seem to be much incentive to use recognizably artificial radio signals for long after you go digital.

Radio is going to be important for planet to ship, ship to ship, and planet to planet communication.

[Impaler[WrG]]

When I applied my own estimates to the Drake equation I came up with a total of exactly 3 civilization in our galaxy which is in high agreement with observations of only 1.

Franky the evolution of an organism with our intelligence is indescribably hard, 99.9% of all species that have ever lived are extinct and of those currently alive only one is capable of technology (dolphins don't have hands). A species typically lasts from 5-20 million years and only very unique environments foster high brain-size and manipulative appendages the two pre-requisites for technology.

Given all that it still seems their should be at least a few ancient Orlons out their claiming a largely empty Galaxy, but we need several conditions to be true for that. First interstellar travel must really be possible and practical enough to be used as a means of spreading. Second the spreading effectively makes the species immortal and Third that technological civilization at that level is also essentially immortal. And lastly that a species that advanced would still feel a need to expand something I find highly dubious.

Thus I personally believe that their are no galaxy spanning empires out their swiftly expanding their borders towards us. Radio contact across short distances (hundreds of light years) is simply not going to happen, at best thousands and tens of thousands might happen and thats about it.

[Geronimo]

Originally posted by DinoDoc
Based on?

Here's a source lifted from a wiki article. knock yourself out.

[Geronimo]

Originally posted by Kuciwalker
\

At some point the raw energy output of a civilization [think dyson-sphere level] becomes detectable.

not by our current methods. Anyway if you nest enough dyson spheres the outermost is almost as cool as the interstellar media so even a dyson sphere could be tough to spot.

[Whoha]

Thus I personally believe that their are no galaxy spanning empires out their swiftly expanding their borders towards us.

Back to the free market, do you think you'd be able to hold humans back if we could meet the technological pre-reqs for building such ships?

I don't think we'd see much of a coherent empire given communications limitations and stl travel, but people would be out there.

[Geronimo]

Originally posted by Whoha


Radio is going to be important for planet to ship, ship to ship, and planet to planet communication.

if it's digital it probably won't look artificial to an observer. Furthermore what about the incentive to use narrow low divergence beams for long distance communication so as to to avoid wasted broadcasting energy? You won't detect that unless you happen to be right in it's path.

[Geronimo]

Originally posted by Impaler[WrG]
Thus I personally believe that their are no galaxy spanning empires out their swiftly expanding their borders towards us.

Only one would have needed to have taken that route in our galaxy to leave artifacts here for us to find even if we do assume that they wouldn't be immortal and might long since have collapsed.

[Whoha]

I think broadcast is going to be cheaper then narrow, there is also the fact that you don't necessarily know where your target will be when he gets your message. He could be moving under power, or the planet he is on will revolve a little bit around the sun.