>> >> Realy ? But with 64 bit or 128 bit adressing space you can address
>> >> every atom on the earth ... Once I mad a calculation about it, but I
>> >> think that 256 bit can address 1/8 of the universe.
So what. IPv6 will be using 128-bit addresses for *hosts*. The point is that some
redundant space allows easy routing even though it may appear to be wasteful.
And the width of the address bus has next to nothing to do with the width of the
processor registers...
>> No, it is around 10^78, maybe 10^80. That would be 259 to 265 bits. So the
>> previous statement about 256 bits being enough for 1/8 of the universe is
>> right, using the 10^78 figure.
>
>
>Hmm. Imagining the size of the universe as, one planet earth for
>every atom in planet earth, is certainly a concise belief. In hopes
>of derailing our cyber-implementiation discussions into full-blown
>basic cosmology, just how exactly are these rough figures arrived at?
Most of the universe is hydrogen. We know the mass of a proton, this is a
very close approximation to the mass of a hydrogen atom. (In cosmology +/- 50% is
quite accurate) We know the mass of the Sun to a high degree of accuracy, the Sun
is a quite normal star. We know to a fair degree of accuracy how many stars there
are in an average galaxy, and to a reasonable approximation the number of galaxies
in the observable universe. Multiply the numbers together and you get an estimate
of the number of atoms in the universe.
We can get another estimate of the total mass of the universe - by the
deceleration of the expansion resulting from the Big Bang - if the universe was
100 times as massive as the estimate derived from the counts, it would already be
contracting towards the Big Crunch, or gnaB giB, if you prefer.
Regards
Brian Beesley
