I was disappointed in the thin, banal issue of SciAm on "Time," but now 
there's a new special issue devoted to "The Once and Future Cosmos."

It's very good, filled with excellent illustrations of models of 
cosmology, key experiments, and what we currently know about the 
structure of the cosmos. Some of the graphics are so good that I am 
tempted to buy a second copy just so I can clip the graphics and put 
them up in places where I can ponder them.

For this list, there's a little bit of discussion of the 
Rees/Linde/Vilenkin/Barrow/Smolin/Tegmark sort of model where new 
universes are created with slightly different laws of physics. This is 
mentioned in a fanciful figure showing such hypothetical pocket 
universes being formed:

"Multiple universes are continuously being born, according to some 
cosmologists. Each universe is shown here as an expanding bubble 
branching off from its parent universe. The changes in color represent 
shifts in the laws of physics from one universe to another." [Figure on 
page 85]

By the way, I'm reading Smolin's "Life of the Cosmos," where he makes a 
good case for his thesis that the cosmos we are in is one strongly 
rigged (basic laws, parameters) so as to have a very high production 
rate of black holes. The idea is similar to the Boostrum sort of 
Bayesian argument about assuming the world we find ourselves in is 

Smolin argues that if a universe creates few or no black holes (for 
example, it expands and collapses in a Planck time, or has no 
aggregations of matter worth mentioning, and so on), it leaves no (or 
just one) children. A universe which creates, say, 10^18 black holes, 
leaves 10^18 children, some of which may leave even more children, and 
so on. Thus, there's a fitness landscape with the x and y axes (in a 
simple diagram) being some set of parameters which affect black hole 
formation and the vertical or z axis being the number of black holes 
(and hence universes, a la Linde, others) created.

While there is no "competition amongst the universes" directly, that we 
know of, differential reproduction is enough, in general, to produce 
evolutionary effects.

After some number of "bounces or black hole formations with slightly 
different laws of physics" the result will be that nearly all universes 
in some multiverse are ones where black hole formation is commonplace.

Smolin argues that we will be able to measure the number of black 
holes, from small (stellar masses) to larger (recently found, it is 
believed, 1000-sun mass black holes, to massive galactic core black 
holes, and, he thinks, reach the conclusion that we are in a universe 
which is "selected" for maximum ease of black hole formation.


By the way, it may also be the case that universes in which 
intelligence is possible are dominant. My notion, refecting some of the 
fantastical fiction of Steven Baxter and Greg Egan, is that advanced 
civilizations will be able to _make_ black holes, possibly in vastly 
greater abundance than astrophysical sources can.

(Yeah, of much smaller mass. And presumably of very short duration. The 
weirdness of spacetime and the insides of black holes are enigmas, but 
it is speculated by some that even a microscopic black hole could have 
a "full cosmos" inside. We don't, at least, have any compelling 
evidence that a galactic core black hole with 10,000 solar masses is 
going to produce a richer or more complete "cosmos inside" than a 
microscopic black hole made up of a few grams or less of our matter.)

Using the same kind of reasoning Smolin uses, a civilization which has 
special accelerators cranking out 10^30 black holes per second, say, is 
going to "outbreed" and thus be more represented, than universes where 
only astrophysical processes are making only a relatively paltry 10^18 
or 10^25 black holes in the age of that universe.

(And, even more speculatively, the difference is not great between the 
number of black holes a single civilization can make and the number a 
million civilizations can make, so it's more significant that a 
universe supports AT LEAST SOME advanced intelligence/civilization than 
that it supports UBIQUITOUS intelligence/civilization. But this 
reasoning is speculative and needs a lot more thought...maybe. Someone 
could probably write a nice Baxterian story with this theme.)

--Tim May, Occupied America
"They that give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." -- Benjamin Franklin, 1759. 

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