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.'
If we're ruling out the possibility of FTL interstellar travel, then I could see why an advanced civilization would send such a signal.
On the other hand, if advanced cultures on other worlds have achieved FTL travel, then they also must communicate with a technology that is faster than light. This is more of what I was referring to when I commented that METI and SETI were on the wrong frequencies.
No, I've got 10,000 years of human history on my side, which shows that mankind has eventually unlocked the secrets to whatever physical universe problem he's ever tried to solve.
You've agreed to, and are locked into a theoretical dogma that you can't see your way out of, because you're using the rules of the only problem solving table you have.
Einstein isn't the final word on the truth of our universe. We simply haven't met the person who will knock him off his pedestal yet.
That makes sense to me, otherwise, the mail would arrive before the phone call.
Until we can communicate FTL or at least receive transmissions, we won't hear any incoming traffic any more than we'd hear FM radio tuned in to AM.
This isn't an engineering problem. What you're saying is 100% equivalent to saying "Someday, we'll violate the Uncertainty Principle if we just set our minds to it," or "Someday, we'll create a Perpetual Motion Machine of the First Kind; 10,000 years of human history convinces me we will."
No.
We won't.
I looked up the total biomass (wet) of the Earth and divided that by the mass of the Earth and came up with a ratio of less than one part in one billion.
"Ubiquitous" and "full" as you use them are subjective terms.
Amen to that. I was pretty peeved when the media and GOP establishment types jumped all over Gingrich's head for talking about returning to the moon. Of course, that should have happened long ago and in a big way. And let's not forget Obama's abandonment of the Constellation program.
Jesus is the gate opening up to salvation, a gate open to everyone.— Pope Francis (@Pontifex) August 27, 2013
I told you to go out and look, and you stuck your head in a book.
Now you're just arguing for the sake of arguing. We're not talking about the mathematical ratio of lifeforms to inorganic matter. We're talking about the ubiquity of life on the planet.
You sound like that clown who wanted to close the U.S. patent office 100 years ago, because "everything's been invented".
Your kind of thinking holds humankind back, because it rails against and resists exploration, query, and imagination. Your close-minded, dogmatic approach to the universe is literally suppressive to discovery and enlightenment. Science has advanced in spite of your type, not because of you. The great minds in our history fought people like you, every step of the way.
For the life of me, I can’t remember the title, but I once read a sci-fi short story about that. As I recall, a scientist developed a force field mechanism which could create a dome over cities to keep ICBM’s from getting through. He ended up finally succumbing to the urge to kill himself.
The end of the story either had someone figuring it out, or maybe the “creators” explaining it - we were some sort of experiment, and just as our biologists place poison at the edges of petri dishes to keep dangerous microbes from escaping, the “creators” planted suicidal impulses in anyone who might devise ways for us to cross certain lines.
That is a pure leap of faith, based on absolutely nothing. The breakthrough you foresee is the ability to step out of this space-time reality, onto some other reality and then step back in. That is pure fantasy.
Where do you think the measurements for biomass and mass come from? What you're trying to do is to get me to substitute your subjective measure for my objective measure. Perhaps you don't know the meanings of the words.
Read a short story about that scenario. Guy in stasis wakes up to tend to course corrections, etc., goes back to sleep. Sees an un-explainable explosion behind the ship.
Wakes up before landing, with the rest of his crew, only to find a big reception from the folks that passed him and got there years ago, and decided to give the original “pioneers” a hero’s welcome...
Explosion was explained as another expedition which disappeared, and was never found. So, the old guys provided the explanation for that.
If it requires faith it is not science.
The same thing is true of superluminal travel. It violates basic laws of physics, concerning which there are no doubts.
Put your money where your mouth is, or go away.
Fred, while I respect your advanced level of education in the area of physics, I also know that the physical sciences have never stopped advancing, and that history is strewn with examples of new discoveries that re-wrote science texts around the world. It’s happened again and again, and will continue to happen, as man increases his understanding of our universe.
Laws of nature that are now considered immutable, will one day be broken or bent by man to suit his will and purposes. Such has it ever been, and will always be.
: - ) Love his tweets. Thanks for the post and ping.
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