Tag Archives: Fermi-Paradox

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Goodbye, Big Bang?

Everyone knows about the Big Bang, right? The explosion-into-being of the entire universe, however many billions of years ago? Of course they do. Trouble is, the Big Bang has always been something of a fudged theory… and now Wun-Yi Shu of the National Tsing Hua University in Taiwan has come up with a new theory that fits a lot of observed evidence far more thoroughly… while dumping on some accepted truths.

Shu’s idea is that time and space are not independent entities but can be converted back and forth between each other. In his formulation of the geometry of spacetime, the speed of light is simply the conversion factor between the two. Similarly, mass and length are interchangeable in a relationship in which the conversion factor depends on both the gravitational constant G and the speed of light, neither of which need be constant.

So as the Universe expands, mass and time are converted to length and space and vice versa as it contracts.

This universe has no beginning or end, just alternating periods of expansion and contraction. In fact, Shu shows that singularities cannot exist in this cosmos.

As with all such theories, not everything fits perfectly:

One of the biggest problems he faces is explaining the existence and structure of the cosmic microwave background, something that many astrophysicists believe to be the the strongest evidence that the Big Bang really did happen. The CMB, they say, is the echo of the Big bang.

How it might arise in Shu’s cosmology isn’t yet clear but I imagine he’s working on it.

Even if he finds a way, there will need to be some uncomfortable rethinking before his ideas can gain traction. His approach may well explain the Type-I supernova observations without abandoning conservation of energy but it asks us to give up the notion of the Big Bang, the constancy of the speed of light and to accept a vast new set of potential phenomenon related to the interchangeable relationships between mass, space and time.

So, yeah, bit of a revolutionary idea. Reading stuff like this always makes me wish I’d knuckled down more at college and gotten to grips with the heavy-lifting end of physics; that way I might have ended up making a living from speculating about how the universe works. What could be more fun?

And while we’re talking cosmology, here’s a Fermi Paradox rethink [via SlashDot]:

… a new approach by Igor Bezsudnov and Andrey Snarskii at the National Technical University of Ukraine.

Their approach is to imagine that civilisations form at a certain rate, grow to fill a certain volume of space and then collapse and die. They even go as far as to suggest that civilisations have a characteristic life time, which limits how big they can become.

In certain circumstances, however, when civilisations are close enough together in time and space, they can come into contact and when this happens the cross-fertilisation of ideas and cultures allows them both to flourish in a way that increases their combined lifespan.

[…]

The parameters that govern the evolution of this universe are simple: the probability of a civilisation forming, the usual lifespan of such a civilisation and the extra bonus time civilisations get when they meet.

The result gives a new insight into the Fermi Paradox. Bezsudnov and Snarskii say that for certain values of these parameters, the universe undergoes a phase change from one in which civilisations tend not to meet and spread into one in which the entire universe tends to become civilised as different groups meet and spread.

Bezsudnov and Snarskii even derive an inequality that a universe must satisfy to become civilised. This, they say, is analogous to the famous Drake equation which attempts to quantify the number of other contactable civilisations in the universe right now.

Of course, the only way to prove the theory is to wait until we can get more data… so you might want to read a book or something in the meantime.

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The Ten Errors of Science Fiction

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Ladies and gentlemen, start your engines – nothing tends to rile science fiction folk so much as folk from outside the ghetto loudly pronouncing that OMFG UR DOIN IT RONG, and this piece by Dr Sam Vaknin should provide great fodder for some hard sf advocacy and righteous ire. So fetch your popcorn, kids, as we find out the ten hidden and fallacious assumptions about extraterrestrials in science fiction!

In all works of science fiction, there are ten hidden assumptions regarding alien races. None of these assumptions is a necessity. None of them makes immanent or inevitable sense. Yet, when we read a sci-fi novel or watch a sci-fi movie we tend to accept all of them as inescapable. They amount to a frame of reference and to a language without which we seem to be unable to relate to all manner of exobiology. We evidently believe that life on Earth is a representative sample and that we can extrapolate its properties and mechanisms of action wide and far across the Universe. The principles of symmetry, isotropy, and homogeneity apply to the physical cosmos: Hydrogen behaves identically in our local galactic neighbourhood as it does in the furthest reaches of the Cosmos. Why shouldn’t life be the same?

“In all works of science fiction”? Vaknin must have a whole lot of reading time on his hands…

Snark aside, Vaknin’s major FAIL here is the classic outsider’s misconception of sf, namely that it’s supposed to be taken literally rather than allegorically*. In other words, he’s quite right in that sf makes assumptions about alien life, but quite wrong in thinking that it matters to sf’s function as a form of entertainment**. Put it this way: if you read science fiction for the pleasure (rather than as a stand-in for a doctorate in exobiology, say), I’d guess there’s a 95% chance Vaknin’s article is a classic case of TL;DR. SETI geeks with time on their hands may get a kick from it, though.

Anyway, George Dvorsky takes Vaknin at something closer to face value than I have the time, expertise or motivation to pull off, and manages to do a pretty good job of popping his tyres:

Sure, I agree that ETIs may be dramatically different than what we can imagine and that they may exist outside of expected paradigms, but until our exoscience matures we should probably err on the side of the self-sampling assumption and figure that the ignition and evolution of life tends to follow a similar path to the one taken on Earth. Now, I’m not suggesting that we refrain from hypothesizing about radically different existence-states; I’m just saying that these sorts of extraordinary claims (like alternative intelligences spawning different quantum realities) require the requisite evidence. It’s far too easy to fantasize about some kind of energy-based hive-mind living in the core of asteroids, it’s another thing to prove that such a thing could come about through the laws of physics [my example, not Vaknin’s].

[…]

Nice try, Vaknin, but the Great Silence problem is more complex than what you’ve laid out.

For all my bitching above, I do actually find things like the Fermi Paradox and the Great Silence to be lots of fun to think about. If you’re looking for an accessible introduction to the idea (and some of the hypotheses presented as solutions), Dvorsky’s blog is a good place to start… but I’d also recommend the book Where Is Everybody? by Stephen Webb, which is full of great starter seeds for Baxterian space opera stories.

[ * Yeah, yeah, hard sf is driven by scientific rigour and plausibility, sure, but it’s still stories told by humans about what it’s like – or may at some point in the future be like – to be a human in a big confusing universe; even Watts’ Blindsight speaks to the human condition and the state of our understanding of life in the universe more than it does the raw facts we have regarding life in the universe, and that’s about as hard an sf novel as I’ve ever read. You can argue that rigidly hard sf (factual to the detriment of story) is the apogee of the genre if you like, but you’d be wrong. ]

[ ** An essay deconstructing the false assumptions made about gender and race in science fiction, however, would be something worth writing, because humans are the true subject of human literature, even when they’re not the subject that takes the limelight on center stage. False assumptions about people need taking apart far more urgently than false assumptions about hypothetical beings we may never meet, IMHO. ]

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Earth and other unlikely worlds

Apologies to Paul Mcauley for pinching the name of his blog for a post title, but it felt appropriate!

In addition to raking over our old friends the Drake Equation and the Fermi Paradox, COSMOS Magazine looks at the possibilty of the sort of planets found in classic space opera actually existing… you know the sort, solid globes of diamond or iron or ice or whatever else.

THE EARTH FORMED in a region of the Solar System’s protoplanetary disc that was relatively rich in the element oxygen. So on top of an iron-rich core, our planet is mostly built out of oxygen-containing silicate rocks. But further out in the protoplanetary disc, the ratio of the elements carbon and oxygen was probably different.

A class of meteorites found on Earth, called enstatite chondrites, may have formed in this region – they have a ratio of carbon to oxygen that is a thousand times larger than the ratio found on Earth.

“If an entire planet were to have condensed from this kind of raw material, it would have ended up enormously different from the Earth,” says Marc Kuchner, an expert on exoplanets at NASA’s Goddard Space Flight Centre near Washington DC.

Built out of relatively more carbon than oxygen, such a planet would still have a metallic iron core, but the outer layers could be composed of ceramics – silicon and titanium carbides – with a shell of pure carbon on top.

These ceramics and graphite would make the entire planet extremely hard and heat-resistant, and it could survive much closer to its star. Even more bizarre is that the high pressure beneath the surface would convert the bottom of the graphite layer into an entire shell of diamond that would be many kilometres thick.

That’s your sensawunda fix for the day, I reckon. And if you’re a fan of the OMG-we’re-so-insignificant angle, try this for size: Earth’s habitable period may nearly be over, at least on a cosmological time-scale [via SlashDot].

“The Sun does not seem like the perfect star for a system where life might arise. Although it is hard to argue with the Sun’s ‘success’ as it so far is the only star known to host a planet with life, our studies indicate that the ideal stars to support planets suitable for life for tens of billions of years may be a smaller slower burning ‘orange dwarf’ with a longer lifetime than the Sun ― about 20-40 billion years. These stars, also called K stars, are stable stars with a habitable zone that remains in the same place for tens of billions of years. They are 10 times more numerous than the Sun, and may provide the best potential habitat for life in the long run.”

Take that, Rare Earth Theory! Turns out we’re not so special after all… though whether that’s reassuring or depressing is a matter for debate.

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You think the Earth is rare? I got a dozen just like it out back…

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Planet EarthOne of the better known responses to the Fermi Paradox is the Rare Earth hypothesis – the supposition that our planet is rare or unique in its ability to harbour life, and that hence we are unlikely to encounter life-forms elsewhere beyond our own biosphere. [image by Aaron Escobar]

Well, George Dvorsky isn’t having any of it.

I’ve always thought, however, that given cosmologically large numbers that this sort of thinking is symptomatic of our small minds and limited imaginations. It’s easy for us to throw up our hands and sheepishly declare that we’re somehow special. Such a conclusion, however, needs to be qualified against the data involved, and by the mounting evidence in support of the notion that ours appears to be a life-friendly universe.

Dvorsky goes on to attack the assumptions of Rare Earthers methodically.

It’s a myth, for example, that it took life a long time to get going on Earth. In reality it was quite the oppoite. Our planet formed over 4.6 billion years ago and rocks began to appear many millions of years later. Life emerged relatively quickly thereafter some 600 million years after the formation of rocks. It’s almost as if life couldn’t wait to get going once the conditions were right.

This isn’t to say that Dvorsky thinks that we’re being visited by little green men on a regular basis, though; he has a more worrying idea about why we’ve not heard from our neighbours yet.

My feeling is that the Rare Earth hypothesis is a passing scientific fad. There’s simply too much evidence growing against it.

In fact, the only thing going for it is the Fermi Paradox. It’s comforting to think that the Great Silence can be answered by the claim that we’re exceptionally special. Rare Earth steers us away from other, more disturbing solutions –namely the Great Filter hypothesis.

Of course, only evidence of alien civilisation will ever answer Fermi’s famous question; it’s always struck me as a kind of science fictional restatement of the argument for the existence of god. Maybe that’s why it’s such a fascinating subject for debate? A bit of teleology never fails to get people thinking…

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Drake equation crunched – 361 civilisations in our galaxy alone?

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Messier-74 galaxyHey, great news for SETI fans! The latest work on the Drake equation suggests that we can all get our Fox Mulder on:

The current research estimates that there are at least 361 intelligent civilisations in our Galaxy and possibly as many as 38,000.

Awesome! Wait, what?

Even with the higher of the two estimates, however, it is not very likely that contact could be established with alien worlds.

Ah. Bugger.

Of course, the Drake Equation is only as good as its input data, and much of that remains wildly speculative. But the above is the result of factoring in the sudden rash of exoplanet discoveries we’ve made in the last few years; according to Centauri Dreams, the little we’ve learned about them means we can simulate the potential parameters of their atmospheres in order to guess how statistically likely they are to harbour the potential for life. Even that’s mostly guesswork, though:

… in biological terms, we are even more up the creek, since we base our thinking on observations of a single biosphere, our own. To keep the number of free parameters to a minimum, Forgan works with “a biological version of the Copernican Principle,” the notion that our Terran biosphere is not special or unique, so that we can think about life on other worlds as sharing many of the same characteristic parameters.

So keep watching the skies, folks! And don’t forget the hypothesis of Futurismic‘s own Mac Tonnies, which suggests that what we think of as extraterrestrials may in fact be something much more local… [image by jimkster]