Seth Lloyd, a physicist at the Midvale School for the Gifted,
has estimated how much information the Universe can contain,
and how many calculations it has performed since the Big Bang1.
Posted on 06/03/2002 10:42:37 PM PDT by sourcery
We are all living inside a gigantic computer. No, not The Matrix: the Universe.
Seth Lloyd, a physicist at the Massachusetts Institute of Technology in Cambridge, has estimated how much information the Universe can contain, and how many calculations it has performed since the Big Bang1.
Lloyd views every process, every change that takes place in the Universe, as a kind of computation. One way of looking at the exercise is to imagine setting up a simulation of the Universe, particle for particle, on a hypothetical super-duper computer.
To simulate the Universe in every detail since time began, the computer would have to have 1090 bits - binary digits, or devices capable of storing a 1 or a 0 - and it would have to perform 10120 manipulations of those bits. Unfortunately there are probably only around 1080 elementary particles in the Universe.
Computer science
Just as clocks were the favourite analogy for complex systems during the age of Newton, now scientists like to compare everything to computers. DNA is sometimes described as digital, and the human brain, consciousness and life itself are discussed as though they all involve computation. So is Lloyd taking it all too far, depicting the Universe as a computer?
Perhaps; but Lloyd has a reputation as a challenging lateral thinker, especially in information theory. Two years ago he calculated the physical limits to computation: the constraints that physical laws place on the power of, say, a laptop-sized computer2. Now he's just doing the same for a Universe-sized computer.
The Universe is computing its own dynamical evolution
--Seth Lloyd, Massachusetts Institute of Technology
The concept of physics as a computational process was articulated by the US physicist John Archibald Wheeler in the phrase "It from Bit". And complexity guru Stephen Wolfram suggests in his recent book A New Kind of Science3 that all of reality might result from a kind of algorithm, like a computer program, being enacted again and again on the underlying building blocks of space and matter.
We tend to associate computation with problem-solving, whereas it isn't clear that there is any 'problem' for the Universe to solve. But the connection between information science and physical processes appears once we think about events on the quantum scale.
Quantum switch
Every fundamental particle has a discrete number of different quantum states available to it. If a particle moves from one quantum state to another, this is rather like switching a bit in a computer from one state (say, 1) to another (say, 0).
"If one regards the Universe as performing a computation", says Lloyd, "most of the elementary operations in that computation consist of protons, neutrons, electrons and photons moving from place to place and interacting with each other according to the basic laws of physics."
What, then, is the Universe computing? "Its own dynamical evolution", says Lloyd. As the computation proceeds, reality unfolds.
He estimated the maximum number of logical operations the Universe has performed by calculating its total energy with Einstein's E = mc2. The energy of any physical system determines how fast it can switch from one quantum state to another - how fast it can compute.
It is computing the answer, we of course we all know is 42.
So we're in a reality emulator? And the Big Bang was a hard boot?
And the programmer has stepped out for coffee... ;)
The universe is itself, not some weak paradigm posited by an MIT grad student. Calling it a computer merely projects onto the cosmos todays latest technological achievement, which is in the abstract the realization that one can order actions and achieve great complexity from simple things.
A more accurate statement in this regard is, rather than the Universe being a computer, that a computer is a Universe.
Yeah that is what you call the big bang.
Seth Lloyd, a physicist at the Midvale School for the Gifted,
has estimated how much information the Universe can contain,
and how many calculations it has performed since the Big Bang1.
When I heard the learned astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much applause in the lecture-room,
How soon unaccountable I became tired and sick,
Till rising and gliding out I wandered off by myself,
In the mystical moist night-air, and from time to time,
Looked up in perfect silence at the stars.
No, because mirrors are not perfectly reflective and therefore attenuate the signal until it disappears below the noise floor of the universe. Lots of reflections aren't infinite reflections.
Low memory isn't no memory. Even virtual images take up a little extra space for each reference to another object. You would still need to store the pointers for the effect to occur.
A pointer is just a metaphor. The point is that the number of optical vectors increases with each reflection, so Kolmogorov complexity of the parallel mirror case is a finite number larger (though not much larger, since much of the vector information is duplicated with each reflection) than the case of a single image. If the Kolmogorov complexity increases, so does the intrinsic memory requirement.
An infinity of nothing is nothing.
I believe it is actually indeterminant.
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