[Link] Cosmological Infancy

by [anonymous]3 min read21st Jul 201322 comments

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Personal Blog

A post by Nick Land who some of you are probably already following either on his blog Outside In or at Urban Future.

There is a ‘problem’ that has been nagging at me for a long time – which is that there hasn’t been a long time. It’s Saturday, with no one around, or getting drunk, or something, so I’ll run it past you. Cosmology seems oddly childish.

An analogy might help. Among all the reasons for super-sophisticated atheistic materialists to deride Abrahamic creationists, the most arithmetically impressive is the whole James Ussher 4004 BC thing. The argument is familiar to everyone: 6,027 years — Ha!

Creationism is a topic for another time. The point for now is just: 13.7 billion years – Ha! Perhaps this cosmological consensus estimate for the age of the universe is true. I’m certainly not going to pit my carefully-rationed expertise in cosmo-physics against it. But it’s a stupidly short amount of time. If this is reality, the joke’s on us. Between Ussher’s mid-17th century estimate and (say) Hawking’s late 20th century one, the difference is just six orders of magnitude. It’s scarcely worth getting out of bed for. Or the crib.

 

For anyone steeped in Hindu Cosmology – which locates us 1.56 x 10^14 years into the current Age of Brahma – or Lovecraftian metaphysics, with its vaguer but abysmally extended eons, the quantity of elapsed cosmic time, according to the common understanding of our present scientific establishment, is cause for claustrophobia. Looking backward, we are sealed in a small room, with the wall of the original singularity pressed right up against us. (Looking forward, things are quite different, and we will get to that.)

There are at least three ways in which the bizarre youthfulness of the universe might be imagined:

1. Consider first the disconcerting lack of proportion between space and time. The universe contains roughly 100 billion galaxies, each a swirl of 100 billion stars. That makes Sol one of 10^22 stars in the cosmos, but it has lasted for something like a third of the life of the universe. Decompose the solar system and the discrepancy only becomes more extreme. The sun accounts for 99.86% of the system’s mass, and the gas giants incorporate 99% of the remainder, yet the age of the earth is only fractionally less than that of the sun. Earth is a cosmic time hog. In space it is next to nothing, but in time it extends back through a substantial proportion of the Stelliferous Era, so close to the origin of the universe that it is belongs to the very earliest generations of planetary bodies. Beyond it stretch incomprehensible immensities, but before it there is next to nothing.

2. Compared to the intensity of time (backward) extension is of vanishing insignificance. The unit of Planck time – corresponding to the passage of a photon across a Planck length — is about 5.4 x 10^-44 seconds. If there is a true instant, that is it. A year consists of less the 3.2 x 10^7 seconds, so cosmological consensus estimates that there have been approximately 432 339 120 000 000 000 seconds since the Big Bang, which for our purposes can be satisfactorily rounded to 4.3 x 10^17. The difference between a second and the age of the universe is smaller that that between a second and a Planck Time tick by nearly 27 orders of magnitude. In other words, if a Planck Time-sensitive questioner asked “When did the Big Bang happen?” and you answered “Just now” — in clock time — you’d be almost exactly right. If you had been asked to identify a particular star from among the entire stellar population of the universe, and you picked it out correctly, your accuracy would still be hazier by 5 orders of magnitude. Quite obviously, there haven’t been enough seconds since the Big Bang to add up to a serious number – less than one for every 10,000 stars in the universe.

3. Isotropy gets violated by time orientation like a Detroit muni-bond investor. In a universe dominated by dark energy – like ours – expansion lasts forever. The Stelliferous Era is predicted to last for roughly 100 trillion years, which is over 7,000 times the present age of the universe. Even the most pessimistic interpretation of the Anthropic Principle, therefore, places us only a fractional distance from the beginning of time. The Degenerate Era, post-dating star-formation, then extends out to 10^40 years, by the end of which time all baryonic matter will have decayed, and even the most radically advanced forms of cosmic intelligence will have found existence becoming seriously challenging. Black holes then dominate out to 10^60 years, after which the Dark Era begins, lasting a long time. (Decimal exponents become unwieldy for these magnitudes, making more elaborate modes of arithmetical notation expedient. We need not pursue it further.) The take-away: the principle of Isotropy holds that we should not find ourselves anywhere special in the universe, and yet we do – right at the beginning. More implausibly still, we are located at the very beginning of an infinity (although anthropic selection might crop this down to merely preposterous improbability).

Intuitively, this is all horribly wrong, although intuitions have no credible authority, and certainly provide no grounds for contesting rigorously assembled scientific narratives.  Possibly — I should concede most probably — time is simply ridiculous, not to say profoundly insulting. We find ourselves glued to the very edge of the Big Bang, as close to neo-natal as it is arithmetically possible to be.

That’s odd, isn’t it?

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Star formation rates in the universe solve this problem.

See my old post on our position in space and time and how typical it likely actually is.
Partially quoted below:

To make a long story short, a survery was made looking into deep space, and back in time up to 11 billion years, of a pretty good proxy of star formation (the emission lines produced by emission nebulae that are lit up like neon lights by the ultraviolet light of freshly-born huge stars). After doing some fancy math to correct for the expansion of space and the like the conclusions are striking - the modern average rate of star formation in the universe is less than 1/30 the peak rate of 11 billion years ago, and half of the stars in the universe are over 9 billion years old. To make matters even more interesting, the empirically-derived relationship between time and star formation actually converges to a finite number of stars when you project it into the future, and at infinity reaches a total number of stars born only 5% more than currently exist today.

95% of stars that will ever exist already exist.

This makes sense and has some interesting implications when you think in terms of galactic evolution and the history of the universe. Grand spirals like our galaxy are nearly the only places in the universe where star formation happens for billions of years on end and produces generations of stars rich in heavy elements. Dwarf galaxies go through one burst of star formation and the supernovas from the big stars blow all the gas out of their weak gravity, stopping star formation. Big elliptical galaxies form with nearly no angular momentum, so all their gas falls to the center, most of it becomes stars in one huge burst of low-metal stars, and the rest gets blown out of the galaxy when the central black hole gets activated. Grand spirals only wind down slowly with time as most of their gas stays away from the center due to angular momentum but their gravity makes sure that (almost) all the gas stays bound, getting more and more enriched in heavy elements with time.

That is, until they collide with each other, which as most galaxies are part of clusters does eventually happen. It will happen to us in another four to five billion years, with andromeda. When this happens, the colliding galaxies go through one burst of star formation and then settle down into another elliptical galaxy. So over time, the number of star forming galaxies only decreases.

So, consider our position in space and time. We are in a grand spiral galaxy, which is the only sort of place that really produces high-metallicity stars. Our star system formed about 1/3 of the way through our galaxy's productive life before it collides with Andromeda (probably more like halfway through its compliment of stars, seeing as even spirals settle down with age), and we find ourselves currently about 2/3 of the way through its productive lifetime. I would call this an utterly typical position for an origin of life as we know it.

More reading on my part makes me say that rather than being the ONLY place with high-metallicity stars, spirals are just by far the most common site for them. But the point still stands.

The stelliferous era refers to the time in which stars live, not the time in which they are forming. The longest-lived tiny stars will still be here a hundred trillion years from now, but there probably will have been almost no NEW stars formed for almost the entirety of their lifetimes.

If life either forms within a few gigayears of the formation of a star or not at all (something I find likely given the history of life on Earth and the state of current research on the origins of life, in fact it's probably that it happens IMMEDIATELY after the formation of a star or not at all) then we should indeed expect to find ourselves near the start of the universe, when stars are still being born.

EDIT: You also just shouldn't expect isotropy in time, there is no reason for it and indeed reasons against it. The universe is expanding. High-density, very interesting stuff happens near the start (after just enough expansion has occurred to provide some room between actual entropy and possible entropy in which structure can exist) and low-density, boring stuff happens the further in time you go forward.

Star formation rates in the universe solve this problem.

That helps, but you also need an assumption that civilisations won't expand and colonise the universe. If there are (or will be) such colonisers, we're still atypical, regardless of star formation rates.

Intuitively, this is all horribly wrong, although intuitions have no credible authority, and certainly provide no grounds for contesting rigorously assembled scientific narratives. Possibly — I should concede most probably — time is simply ridiculous, not to say profoundly insulting. We find ourselves glued to the very edge of the Big Bang, as close to neo-natal as it is arithmetically possible to be.

That’s odd, isn’t it?

Why would anyone expect our intuitions to be accurate for universe creation events?

Some people believe that living today, assuming the growth of humankind, is an anthropic evidence that the end is near (otherwise we would be much more likely born later). If we apply the same thinking to the universe as a whole, and assume that if a species masters interstellar travel they can grow even more, it is an anthropic evidence that we will soon destroy the whole universe. Or at least that every species in our position either goes extinct or destroys the universe.

To try an optimistic interpretation, it is also possible that we will soon create a Friendly AI, which will discover that our extrapolated volition prefers preserving the existing minds to creating new ones, and since the energy of the universe is great but finite, creating new sapient beings will be forbidden to maximize the utility of the existing ones. Then the antropically most likely position is to be born a few decades before the Friendly AI is built.

(Anyone who takes this seriously, remember the Wizard's First Rule -- people will believe a lie because they want to believe it's true, or because they are afraid it might be true. I provided both options here.)

Doesn't the anthropic principle provide some difficulty for the latter solution as well - why should we find ourselves at the very beginning of such preposterously long lifespans?

*Our* extrapolated volitions might turn out to prefer immortality over reproduction, but it would be reasonable to guess that over all possible intelligent species, this would be relatively rare: Living things live to reproduce, literally. They're all about reproducing. They like surviving too but it's never the root goal.

So even if our CEV did turn out to favor immortality over reproduction, we would still find ourselves somewhere improbable, and we would still have to wonder, why?

I can imagine a sort of compromise CEV... Say we accept that immortality and reproduction are mutually exclusive. What if we ended up choosing a softer, less tragic kind of mortality where post-organic modes of communication allow all knowledge to be passed from parent to child, all projects continued. Might that be the norm instead?

Inflationary multiverse is essentially infinite. But as you take a slice through (a part of) the multiverse, there is way more young universes. The proportion of universes of given age is inversely (exponentially, as in memoryless distribution) proportional to the age. This resolves the doomsday paradox (because our universe is very young relative to its lifespan). http://youtu.be/qbwcrEfQDHU?t=32m10s

Another argument to similar effect would be to consider a measure over possible indices. Indices pointing into old times would be less probable -- by needing more bits to encode -- than indices pointing to young times.

Our universe might be very old on this picture (relative to the measure), so the conclusion regarding Fermi paradox is to update towards the "great filter in the past" hypothesis. (It's more probable to be the first observer-philosopher having these considerations in one's corner of a universe.)

See also http://www.youtube.com/watch?v=jhnKBKZvb_U

I don't see a need for isotropy of the Universe. We may very well live on the edge of the World.

[-][anonymous]8y 2

But experimentally, the Universe doesn't look anisotropic on large scales.

It’s not a need but a probability issue. We may indeed live on the edge of the World, it’s just surprising because the edge of the world is much smaller than the rest of it.