Yakk

Please replace 1) with "Humanity is the only intelligent life in the Galaxy", or even in the local cluster of Galaxies.

The Universe is BIG, and the Milky Way is small. We are near the edge, and 30,000 light years out. We have neigbours on the order of 4 light years away.

The 2nd nearest spiral Galaxy is 12 million light years away.

Here to the nearest star is 3 million times closer than such a hop, skip and jump.

We can currently send ships to Pluto, which is about 34 thousand light seconds away. Alpha Centauri is about 5 million light seconds away.

Distance to Alpha C/Distance to Pluto = 160.
Distance to 2nd nearest Galaxy/Distance to Alpha C = 3,000,000

I guess you could argue that a Galaxy colonized by intelligent life would be easy to see. But, the claim that "intergalaxy" or "inter galactic cluster" colonization is difficult is easier to swallow than "we can't make it next door".

All we need is the ability to make a ship capable of surviving in vacuum for a few centuries. Pushing it isn't that hard. And if we really needed help braking, send 5 or 50 ships, 4 or 49 of which fire lazers back and help the first ship slow down.

A society capable of both controling the energy required for interstellar travel, which doesn't destroy itself through use of such levels of energy, is another problem.

Angels, Abductions and UFO's can all be explained. Someone made a machine recently that gives you the feeling of a familiar, disembodied presence, by shoving E-M fields into your brain.

Either the aliens are damn good at hiding right under our noses, or it's a matter of brain farts.

*nod*, that is tricky. So, if you can't support life, don't send life.

Why is it unlikely? Alpha-C is only 160 times further away than Pluto. We can send probes to Pluto without mechanical breakdown.

Now, all we need to send is a Van Neumann machine (in one piece or in many), going a bit faster, with some means of braking, and capable of landing on an asteroid.

Now, by 'all we need' I am describig an endevour that makes the Apollo mission look like a walk in the park. The only 'hard' part is building a 'small' self-contained Van Neumann machine (ie, one much smaller than the industrial civilization and supporting ecosystem Van Neumann machine we have).

While a 300 to 3000 year journey seems reasonable (1% or 0.1% of lightspeed trip to a nearby star), a 100,000,000 to 1,000,000,000 year journey (same speed trip between Galaxies) is less so.

In some ways, it isn't more wonkey than heavier-than-air flight, or faster-than-sound flight. Only in some ways.

My biggest objection to them is all forms of FTL-travel seem to give you time travel and causality violation. It doesn't matter if you take shortcuts -- if you take 2 trips involving 2 shortcuts, you can arrive before you leave.

You have to invent physics to avoid causality violations (either reality-splitting or some kind of background reference frame that only applies to FTL travel).

Oh, and you can also rely on the weak anthropomophic principle. If intellgence beating you to a planet makes it basically impossible for intelligence to evolve and develop, it shouldn't be surprising that as a developing intelligence we don't see other intelligences around. In other words, someone had to be first -- and if the first guy prevents the later guys, then everyone is first.

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Last edited by JHVH : 10-29-4004 BC at 09:00 PM. Reason: Time for a rest.