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Relativistic Kill Vehicles and the Fermi Paradox

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  • #31
    well, that and having the technology to detect such intelligent life.

    there could be a civilization undergoing an Industrial Revolution about 100 year light-years away and we'd never know. of course, i believe the Hawking theory that if an actual advanced technological civilization existed, we'd best not advertise our presence until we were CERTAIN that we had technological overmatch.
    There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "My ignorance is just as good as your knowledge."- Isaac Asimov

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    • #32
      Originally posted by Monash View Post
      As for (merely) ballistic threats to Earth, unless a purely space based political entity develops in the next century or so I can't see a deliberate attack as opposed to an accident occurring. First unless the asteroid in question is of minimal size you risk severe damage to your homeland in addition to that of your enemy. Secondly, apart from a few closely monitored rocks that pass near the Earth/lunar gravity well, most likely choices would take months if not years to de-orbit. When your enemy can launch a missile strike with a response time of 45 minutes or so who can wait that long for retaliatory action?

      De-orbiting an asteroid also allows plenty of time for interception in one form or another. Now accidents on the other hand .....
      You do know I said EXTINCTION LEVEL EVENT, right?
      Chimo

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      • #33
        Yes, but my point was the timing issue. An ELE requires a large impacter, most of which have been mapped and few of which pass close to Earth during their normal orbits.

        So as a first strike weapon it's going to take months or even years to arrive using currently foreseeable tech. This gives your opponent plenty of time to either try for an intercept or if that fails get his own punch in first - probably with everyone else on the planet joining in. And they will be using ordinary bombs and rockets, all of which operate on a vastly shorter decision loop than any asteroid.

        If on the other hand it's a retaliatory strike your aiming for, (say using a pre-positioned de-orbiter on a dead man switch) you still have the same problem i.e. months of time for your opponent to react. And of course if you can reach and pre-position a platform of some sort in the asteroid belt you would have to assume your enemies have the capacity to at least launch countermeasures against incoming threats.

        As I said however this would all change if a space based political entity, say a consortium of mining stations or outer planet colonies decided Earth was getting to bossy. Then you would have someone with the means to turn off all the lights down here and timing is no longer an issue.

        Also as noted previously timing becomes irrelevant if moving asteroids into near Earth orbits for resource extraction becomes commonplace and the World is used to seeing large rocks being de-orbited towards Earth. Then you could, I suppose potentially hide a deliberate attack under the guise of a mining op gone wrong. Although again you'd have to think the World was alert to this danger and would put countermeasures in place.

        I suppose some Putinesque madman could decide to create such a weapon in the belief that if a war started and he or she is losing then they are going to try and take everything else with them but it would be a stretch to pull off. If only because it would be hard to keep such a project secret for long and once disclosed it could be readily countered.
        Last edited by Monash; 29 Mar 18,, 07:29.
        If you are emotionally invested in 'believing' something is true you have lost the ability to tell if it is true.

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        • #34
          Originally posted by WABs_OOE View Post
          You do know I said EXTINCTION LEVEL EVENT, right?
          Humans are the most adaptable species on the planet, and we're generalists as far as diet goes. I don't think something like a Chicxulub impactor would do us in. An impactor would have to be even bigger than the 65-million year ago asteroid to ensure human extinction.
          "Every man has his weakness. Mine was always just cigarettes."

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          • #35
            Originally posted by astralis View Post
            well, that and having the technology to detect such intelligent life.

            there could be a civilization undergoing an Industrial Revolution about 100 year light-years away and we'd never know. of course, i believe the Hawking theory that if an actual advanced technological civilization existed, we'd best not advertise our presence until we were CERTAIN that we had technological overmatch.
            I agree with Dr. Hawking's position.
            "Every man has his weakness. Mine was always just cigarettes."

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            • #36
              Originally posted by Ironduke View Post
              Humans are the most adaptable species on the planet, and we're generalists as far as diet goes. I don't think something like a Chicxulub impactor would do us in. An impactor would have to be even bigger than the 65-million year ago asteroid to ensure human extinction.
              Don't see how we can survive decades long crop failures.
              Chimo

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              • #37
                Originally posted by Ironduke View Post
                Humans are the most adaptable species on the planet, and we're generalists as far as diet goes. I don't think something like a Chicxulub impactor would do us in. An impactor would have to be even bigger than the 65-million year ago asteroid to ensure human extinction.
                There's a spirited debate over whether or not the impactor and it's associated intense (hours long) infrared radiation pulse ignited the entire terrestrial biosphere killing exposed animals or just the Americas with only very intense fires in the rest of the world. Regardless the effects of the following massive occlusion of sunlight and global acid rain are ample. While the worst of the dust in the atmosphere blocking nearly all sunlight lasted about a year, the primary killer of plant life across the globe was sulfuric acid aerosols that stuck around in the stratosphere for a decade and continued to occlude about 50% of the light reaching the surface.

                Plant life that relied on photosynthesis died off almost entirely and fungus reigned supreme until the atmosphere began to clear. The creatures that survived were either insects or worms that fed on all the dead and dying animal and plant life or very small creatures mostly birds or rat sized mammals that could live in little burrows where they were protected from the harsh environment, and feed on insects and worms. All non-avian terrestrial dinosaurs perished.

                Humans can eat a variety of things, but finding enough food to support human sized warm blooded (high caloric requirement) creatures would present a severe challenge. The fact that only very small mammals survived, eating bugs and fungus doesn't give me a lot of hope for humanity in that situation.

                Perhaps between seed banks and canned food enough people will survive to eventually repopulate the planet, but it wouldn't be much of a world to live in. We better be vigilant about allowing a mine shaft gap to develop...
                Last edited by SteveDaPirate; 29 Mar 18,, 21:41.

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                • #38
                  There is evidence in NZ of large scale forest fires fires at (in a geological sence) the time of impact. There was extensive burning however it must be remembered that, depending on the geographic location there would have been:

                  A) fire resistant species that were adapted to seasonal burn offs;
                  B) lots of dormant plants and seeds buried under winter snow/ice cover.

                  So the impact on the strike on plant life in terms of fire were not necessarily as severe as might be expected. The acid rain is another issue and apparently this was particularly bad because random chance had the meteor hit a region geologically rich in lime stone which massively amplified the acidity of the fallout.

                  Still again adapted/tough, dormant or buried plant life could ride out the first 12 months easily enough. Aquatic plant life would really suffer.

                  As for animals, yep all the big species except perhaps crocs took a king hit. Small insectivores and seed/plant eaters obviously coped well enough though.

                  If it happened again (same sized or smaller impacted)? Well I suspect a few isolated communities oh humans might have a chance of survival. Those used to living off the land in cold climates or ones with access to the sea - and who somehow managed not to be drowned by the initial tidal waves that is. Hard to say though whether there would be enough survivors to ensure our long term existence as a species, given the restricted gene pool etc.
                  Last edited by Monash; 30 Mar 18,, 06:47.
                  If you are emotionally invested in 'believing' something is true you have lost the ability to tell if it is true.

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                  • #39
                    Originally posted by Monash View Post
                    Still again adapted/tough, dormant or buried plant life could ride out the first 12 months easily enough. Aquatic plant life would really suffer.
                    But is it anything we can eat?

                    Originally posted by Monash View Post
                    If it happened again (same sized or smaller impacted)? Well I suspect a few isolated communities oh humans might have a chance of survival. Those used to living off the land in cold climates or ones with access to the sea - and somehow who managed not to be drowned by the tidal waves. Hard to say though whether there would be enough survivors to ensure our long term.existence as a species, given the restricted gene pool etc.
                    There's the other issue of oxygen. Without photosynthesize plants, our oxygen levels would drop dangerously low.
                    Chimo

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                    • #40
                      Originally posted by WABs_OOE View Post
                      But is it anything we can eat?
                      That's the big question. At a guess - near the sea you have access to seaweed/kelp plus shell fish and fish etc, once things have settled down in terms of tidal waves etc (who know how long that will take i.e. weeks, months, years?) You are from Canada so I would bow to your local knowledge as to how survivors would cope in northern European climates, however (again guessing) in the immediate aftermath and no particular order I would go for:

                      - preserved food stocks in areas where preparing such is normal due to the prolonged winters;
                      - I would also be salting/preserving surviving or just killed food animals like my life depended on on it - which it does;
                      - edible fungi, herbage, nuts etc.
                      - if it gets really bad, you go all 'The Road' on other survivors (FYI not something I like to contemplate.)

                      Originally posted by WABs_OOE View Post
                      There's the other issue of oxygen. Without photosynthesize plants, our oxygen levels would drop dangerously low.
                      Not so much of a problem (I think - expert advice needed) because;

                      - most of the other living organisms that use oxygen have been killed off;
                      - the majority of the oxygen in the biosphere comes from the oceans via algal photosynthesis. This will drop in the immediate aftermath of the impact but I believe a lot strains can and do produce oxygen under low light conditions.

                      I think we would be running off 'reserves' in the short term however.
                      Last edited by Monash; 30 Mar 18,, 06:45.
                      If you are emotionally invested in 'believing' something is true you have lost the ability to tell if it is true.

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                      • #41
                        Originally posted by Monash View Post
                        Not so much of a problem (I think - expert advice needed) because;

                        - most of the other living organisms that use oxygen have been killed off;
                        - the majority of the oxygen in the biosphere comes from the oceans via algal photosynthesis. This will drop in the immediate aftermath of the impact but I believe a lot strains can and do produce oxygen under low light conditions.

                        I think we would be running off 'reserves' in the short term however.
                        You forget the fires that would be consuming the oxygen and turning it into CO2.
                        Chimo

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                        • #42
                          Originally posted by WABs_OOE View Post
                          You forget the fires that would be consuming the oxygen and turning it into CO2.
                          Me bad, you are correct. But there is lot of oxygen and only so much combustible plant life. I assume that if there was enough oxygen to support small birds and mammals humans, at low altitudes at least should be able to survive. What plant life that exists will be attempting to regrow within a year or so and the oceans will still be pumping it out albeit at a diminished rate.

                          We really need an expert in ecology or atmospheric science to answer the question properly.
                          Last edited by Monash; 30 Mar 18,, 12:39.
                          If you are emotionally invested in 'believing' something is true you have lost the ability to tell if it is true.

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                          • #43
                            Originally posted by WABs_OOE View Post
                            Don't see how we can survive decades long crop failures.
                            Humans have undergone population bottlenecks before. I think some 70-80,000 years ago there were only a few tens of thousands of us. There's enough non-perishable stored food among 7.5 billion of us to feed a few tens of thousands for decades long.
                            "Every man has his weakness. Mine was always just cigarettes."

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                            • #44
                              Originally posted by citanon View Post
                              Finally, out of all of the above, if intelligent life emerges, is it technological life? What if you had an ocean world with very smart alien dolphins who have no use for technology what so ever? Seems like the chances of intelligent technological life existing at the same time within a million year time span might be quite small.
                              Dolphins do make limited use of technology. They put sponges on their snouts when they forage for food they can eat that's buried under the ocean bed, and play "pass the seaweed", which I suppose is the dolphin form of football. Indeed, it is more than possible for a completely sentient species to emerge without opposable digits or even say, grasping tentacles. Dolphins certainly have language and dialects, cultures and subcultures, and can be generally regarded as sentient.
                              Last edited by Ironduke; 30 Mar 18,, 19:48.
                              "Every man has his weakness. Mine was always just cigarettes."

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                              • #45
                                Originally posted by Ironduke View Post
                                Humans have undergone population bottlenecks before. I think some 70-80,000 years ago there were only a few tens of thousands of us. There's enough non-perishable stored food among 7.5 billion of us to feed a few tens of thousands for decades long.
                                Not within walking distance.
                                Chimo

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