Posted on 08/26/2013 4:29:42 PM PDT by LibWhacker
(Phys.org) —Scientists as eminent as Stephen Hawking and Carl Sagan have long believed that humans will one day colonise the universe. But how easy would it be, why would we want to, and why haven't we seen any evidence of other life forms making their own bids for universal domination?
A new paper by Dr Stuart Armstrong and Dr Anders Sandberg from Oxford University's Future of Humanity Institute (FHI) attempts to answer these questions. To be published in the August/September edition of the journal Acta Astronautica, the paper takes as its starting point the Fermi paradox – the discrepancy between the likelihood of intelligent alien life existing and the absence of observational evidence for such an existence.
Dr Armstrong says: 'There are two ways of looking at our paper. The first is as a study of our future – humanity could at some point colonise the universe. The second relates to potential alien species – by showing the relative ease of crossing between galaxies, it makes the lack of evidence for other intelligent life even more puzzling. This worsens the Fermi paradox.'
The paradox, named after the physicist Enrico Fermi, is something of particular interest to the academics at the FHI – a multidisciplinary research unit that enables leading intellects to bring the tools of mathematics, philosophy and science to bear on big-picture questions about humanity and its prospects.
Dr Sandberg explains: 'Why would the FHI care about the Fermi paradox? Well, the silence in the sky is telling us something about the kind of intelligence in the universe. Space isn't full of little green men, and that could tell us a number of things about other intelligent life – it could be very rare, it could be hiding, or it could die out relatively easily. Of course it could also mean it doesn't exist. If humanity is alone in the universe then we have an enormous moral responsibility. As the only intelligence, or perhaps the only conscious minds, we could decide the fate of the entire universe.'
According to Dr Armstrong, one possible explanation for the Fermi paradox is that life destroys itself before it can spread. 'That would mean we are at a higher risk than we might have thought,' he says. 'That's a concern for the future of humanity.'
Dr Sandberg adds: 'Almost any answer to the Fermi paradox gives rise to something uncomfortable. There is also the theory that a lot of planets are at roughly at the same stage – what we call synchronised – in terms of their ability to explore the universe, but personally I don't think that's likely.'
As Dr Armstrong points out, there are Earth-like planets much older than the Earth – in fact most of them are, in many cases by billions of years.
Dr Sandberg says: 'In the early 1990s we thought that perhaps there weren't many planets out there, but now we know that the universe is teeming with planets. We have more planets than we would ever have expected.'
The Acta Astronautica paper looks at just how far and wide a civilisation like humanity could theoretically spread across the universe. Past studies of the Fermi paradox have mainly looked at spreading inside the Milky Way. However, this paper looks at more ambitious expansion.
Dr Sandberg says: 'If we wanted to go to a really remote galaxy to colonise one of these planets, under normal circumstances we would have to send rockets able to decelerate on arrival. But with the universe constantly expanding, the galaxies are moving further and further away, which makes the calculations rather tricky. What we did in the paper was combine a number of mathematical and physical tools to address this issue.'
Dr Armstrong and Dr Sandberg show in the paper that, given certain technological assumptions (such as advanced automation or basic artificial intelligence, capable of self-replication), it would be feasible to construct a Dyson sphere, which would capture the energy of the sun and power a wave of intergalactic colonisation. The process could be initiated on a surprisingly short timescale.
But why would a civilisation want to expand its horizons to other galaxies? Dr Armstrong says: 'One reason for expansion could be that a sub-group wants to do it because it is being oppressed or it is ideologically committed to expansion. In that case you have the problem of the central civilisation, which may want to prevent this type of expansion. The best way of doing that get there first. Pre-emption is perhaps the best reason for expansion.'
Dr Sandberg adds: 'Say a race of slimy space aliens wants to turn the universe into parking lots or advertising space – other species might want to stop that. There could be lots of good reasons for any species to want to expand, even if they don't actually care about colonising or owning the universe.'
He concludes: 'Our key point is that if any civilisation anywhere in the past had wanted to expand, they would have been able to reach an enormous portion of the universe. That makes the Fermi question tougher – by a factor of billions. If intelligent life is rare, it needs to be much rarer than just one civilisation per galaxy. If advanced civilisations all refrain from colonising, this trend must be so strong that not a single one across billions of galaxies and billions of years chose to do it. And so on.
'We still don't know what the answer is, but we know it's more radical than previously expected.'
Gold plated latinum, should do it!
42
What do you think about METI (Messaging to Extra-Terrestrial Intelligence), the ‘proactive SETI?’
David Brinn doesn’t like it, I take it there were a lot of scientists that quit their SETI connections when their arguments against it were ignored. I guess they have formed a SET dissidents group over it.
http://www.davidbrin.com/shouldsetitransmit.html
Freegards
“Come let Us make Man in Our image and likeness...”
And where do you propose to get enough negative mass to build one?
Yes, I'm familiar with the term, and have read quite a bit on the subject. Michael Cremo wrote a (now) famous book on the topic.
Over the last hundred years or so, thousands of artifacts have been discovered which don't fit the accepted paradigm of human history.
"Daedalus was to be a two stage spacecraft, with stage one carrying 46,000 tonnes of fuel and stage two carrying 4000 tonnes. After a total boost phase of nearly four years, it would be traveling at its top speed of 12.2 percent the speed of light, and would reach its target (Barnard's Star, located about six light years away) in 50 years."
The problem with such a project, is that within twenty years of launch, the folks back home will have already figured out how to build a craft that far exceeds the speed of the one that's en route.
If they perfect the design, then send it on its way, it would probably overtake the first craft, and maybe even be home before it arrived at its destination.
I think that timescales of half a century will discourage developers and visionaries from embarking on such projects. They well know the pace of discovery, and will probably keep working until they've got a propulsion system that can get a spacecraft to Barnard's Star a whole lot quicker.
The Fermi paradox doesn't depend just upon signals. Many claim an advanced other civilization, if it exists in our galaxy, would have had the time to build a self replicating ship which could visit another star, do some investigation, and build a few copies of itself from raw materials at the new system, which would then go investigate new stars.
This would lead to a geometric increase of stars visited, and the civilization would have had enough time to have visited every star in the galaxy by now.
Various civilizations have already collapsed. It is just that the collapse didn't wipe out our species. Mayans, Romans, Egyptians, Chinese, Japanese, and Indians have all collapsed, mostly from internal, not external forces. I am convinced we are undergoing another one presently.
I’m referring to “Genesis: The Scientific Quest for Life’s Origins” by Robert Hazen (2005). Good read.
Thanks! That was a very good little sci- fi short story. Allow me to return the favor. I remember reading this in a readers digest many years ago while sitting in a doctors office. Enjoy
http://manybooks.net/_scripts/download-ebook.php
What’s the title? You link gives me suggestions but nothing solid.
You can’t go back in time even if you could find a way to travel faster than the speed of light. Time dilation doesn’t work that way, because you can’t dilate something less than zero.
“The moon and Mars perhaps[....]”
You’ve got it all wrong. You are thinking in the pattern of trying to copy Earth, which cannot be done in this Solar System, and its a bad choice for the same reason staying on Earth is a bad choice. The Earth’s gravitational field is a magnet for inviting destructive impacts, and it also make surface to orbit transport prohibitively expensive in energy and financial costs.
Mars has some similar and some even greater problems. The Martian atmosphere is too thin for atmospheric braking of deorbiting spacecraft. The Martian atmosphere is too thin. Increasing the size of the Martian atmosphere is hampered by the advanced losses of atmosphere due to insufficient gravity and lack of a strong magnetic field. The lack of the magnetic field presents problems on the surface with incident radiation from the Sun and outer space. Then there are a plethora of other problems.
The future of most of humanity is among the asteroids. Mining out multiple galleries and levels of the interior of the larger asteroids yields more arable land and freshwater lakes than are found on the Earth in just one large asteroid. There are many of the large asteroids and dwarf planets out there and within reach, and there are countless thousands more of them of smaller sizes. There is enough water out there to fill a multitude of Earth oceans, and this water can be used to crreate vast lakes and seas INSIDE of these asteroids.
Once humans have learned to turn asteroids into habitats, asteroids can be used to transport human communities throughout the galaxy at sub-light speeds. They can spread new colonies along the paths of their journeys.
With your examples, the more we understood science the more likely it was to accomplish them.
With interstellar travel, the more we understand the science the LESS LIKELY it seems possible.
Life is rare. By objective measures it’s rare on Earth, and even rarer in other parts of the Solar System, and most likely non-existent. And this is in a Universe that is “fine tuned” just right to allow life.
Sorry. Its Arena by Fredric Brown.
Thanks.
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