Yes, those five global extinction events haven't been much of a drag for the single cell organisms, bacteria and other really small creatures, but it kinda sucks if you weigh more than a rat. At the end of the Permian period, over 90% of all species died, yay. And that was a pretty rubbish time in Siberia, too...We have used up all the easily accessible ore and fossil energy reserves on the planet. If our current civilisation comes crashing down and we regress to a low technology, post industrial society, it will be extremely hard to bootstrap out of that again.No more oil in Texas at a depth of 20 feet, no easily accessible copper or iron, apart from the ruins of the cities. We have chewed this planet up pretty good so far, and are not leaving much on the plate. If we miss this window of opportunity, which could close any day now, if somebody starts a nuclear war or the global economy really tanks, we will not get of this rock. And developing the technology won't cost more than the average little dirty war that we are starting every few years.War, disease, rapid climate change, economical collapse, totalitarian regimes, AI, oh yes, meteor coming our way while we are to busy staring at our cellphones.My 2 cents worth as geologist and environmental scientist...
I believe the leading contender for explaining the Fermi Paradox is that something/someones are very quiet, careful, deadly, and jealous--and they go around stomping on emerging civilizations prophylactically.
What is probably driving Stephen Hawking’s thinking is the Drake equation and Fermi’s Paradox. Although the Drake equation was not intended to give absolute numbers for the number of technologically advanced intelligent life it can get you close enough to suggest some very real possible outcomes. We don’t have enough information, at this time, to truthfully fill in the Drake equation but we are making very good progress toward filling in all but the last variable. It is this last variable where Fermi’s Paradox comes in. With the limited information, we have to fill in the Drake equation it is becoming quite obvious that the last parameter is the most critical. This last parameter is the average life expectancy of a technologically advanced society. With the limited information we have for the Drake equation if this last parameter is over 10,000 years not only should technologically advanced intelligent life be readily observable but most likely should have visited us multiple times by now. And this is the Fermi’s Paradox. Where are all of these technologically advanced intelligent societies? In fact, it has been estimated that if this last parameter is 1000 years with our ongoing SETI surveys we should have seen something by now. As we fill in more of the Drake equation it is been suggested that this last parameter needs to be in the hundreds of years. If that is the case then we have used up almost half of this number already.Nobody really knows what the answer to Fermi’s Paradox is. There are many suggested possible theories to this paradox. The most worrisome ones in this particular case are not the knowns but the unknown possibilities.
Quote from: Oli on 05/08/2017 08:10 amNo extinction event could render Earth less habitable than Mars or other places in the solar system.So even if one believes the doomsday cultists (which I don't, I think they're all bonkers), it's no argument for colonizing the solar system.Sun turning into a red giant certainly will. In the long term (more than a billion years), Earth is doomed and space is the only way for humanity (and life in general) to survive. And in order to colonize space, we need to have an advanced technological society. Merely surviving on Earth is not enough, or it will be our tomb. Now, can you guarantee that current advanced technological society on Earth will be a norm, and not just a temporary exception? You cannot. Therefore we should seize the opportunity while it lasts and attempt to expand into space now, since we may not get another chance.
No extinction event could render Earth less habitable than Mars or other places in the solar system.So even if one believes the doomsday cultists (which I don't, I think they're all bonkers), it's no argument for colonizing the solar system.
Quote from: DAZ on 05/07/2017 06:33 pmWhat is probably driving Stephen Hawking’s thinking is the Drake equation and Fermi’s Paradox. Although the Drake equation was not intended to give absolute numbers for the number of technologically advanced intelligent life it can get you close enough to suggest some very real possible outcomes. We don’t have enough information, at this time, to truthfully fill in the Drake equation but we are making very good progress toward filling in all but the last variable. It is this last variable where Fermi’s Paradox comes in. With the limited information, we have to fill in the Drake equation it is becoming quite obvious that the last parameter is the most critical. This last parameter is the average life expectancy of a technologically advanced society. With the limited information we have for the Drake equation if this last parameter is over 10,000 years not only should technologically advanced intelligent life be readily observable but most likely should have visited us multiple times by now. And this is the Fermi’s Paradox. Where are all of these technologically advanced intelligent societies? In fact, it has been estimated that if this last parameter is 1000 years with our ongoing SETI surveys we should have seen something by now. As we fill in more of the Drake equation it is been suggested that this last parameter needs to be in the hundreds of years. If that is the case then we have used up almost half of this number already.Nobody really knows what the answer to Fermi’s Paradox is. There are many suggested possible theories to this paradox. The most worrisome ones in this particular case are not the knowns but the unknown possibilities. In the book, alone in the Universe, John Gribbin argues that we are alone in the galaxy and perhaps in the Universe. If we are the only ones in the galaxy that would explain why nobody has visited us. I wasn't crazy about his book but I tend to agree with him that there may only be one advanced civilization per galaxy.
The thing is, even if other civilizations aren't actively out there exploring/ colonizing/ mining/ whatever, we should have seen at least their signature. Sure, we as a planet radiate less and less energy away from our planet as we mature our technology - terrestrial high energy transmitters have given way to cable and focused beams to satellites- but our past still is out there radiating away from earth. So would be true for other intelligent species. And odds have it this would have been happening for billions of years - so where are those signatures? Where are all those countless "pasts"?
The great filter concept certainly still holds some probability, and when you look at our own little planet with that in mind, it's a bit chilling.
The official score is: Earth surviving an apocalypse: 5 Species visiting Earth seeking refuge from their own apocalypse: 0Let's say the next apocalypse sterilizes the Earth into an iron oxide dust bowl. There is never a static unchanging condition with any object in the universe. Eventually life will continue.If someone is so easily able to foresee an imminent apocalypse, why are they not understanding the implications of attempting a journey into a certain demise by a 1000'year journey into space (micrometeorites, radiation, lack of any resources, etc)? If aliens had visited here, it's likely their home world is in worse shape. I fear that somebody is just trying to sell their doomsday books on other worlds. unfortunately, somebody should explain to the doomsday authors that aliens won't want to read this type of literature.You cannot equate a concept of going nowhere fast with the idea that you are doing something meritorious. In other words, transporting the world's population to Siberia would not be a noble cause. Actually Siberia is better than Mars because it is warmer and ACTUALLY HAS OXYGEN.
We have already discovered many extrasolar planets. Advanced civilizations doing such observations for millions of years probably have long ago catalogued every potentialy habitable planet in the galaxy. They very likely know about Earth being a planet with life. It is not a thing that can be hidden or overlooked, IMHO.
I think to really find a new home we need to find a home which is similar to earth and that's going to mean interstellar travel in a Noah's arc type ship which can haul 10s of thousands plus all our technology.
In the book, alone in the Universe, John Gribbin argues that we are alone in the galaxy and perhaps in the Universe. If we are the only ones in the galaxy that would explain why nobody has visited us. I wasn't crazy about his book but I tend to agree with him that there may only be one advanced civilization per galaxy.