[Sorcerer]

http://en.wikipedia....aryon_asymmetry

If all the black holes in the universe were made of antimatter would it balance all the matter?

IE would the problem of why there is so much matter left over from the big bang be solved?

Would the question of why there was/is an imbalance between matter and antimatter in black holes be more of a problem than the original CP violation idea?

[guenter]

Sorcerer, on 29 December 2011 - 04:23 AM, said:

If all the black holes in the universe were made of antimatter would it balance all the matter?

No, at least not according to the present knowledge. The matter including dark matter exceeds the matter of the black holes by far. Further, the microwave background shows no signature of matter-antimatter annihilation.

[imatfaal]

guenter, on 29 December 2011 - 04:42 PM, said:

No, at least not according to the present knowledge. The matter including dark matter exceeds the matter of the black holes by far. Further, the microwave background shows no signature of matter-antimatter annihilation.

Guenter - re the CMBR footprint for antimatter/matter annihilation - how would we know? Prior to the surface of last scattering any radiation from am/m annihilation would have been absorbed by the free plasma. The only radiation of the CMBR is that remnant of the emission radiation of hot plasma (top of UV range) - that's why it approaches homogeneity so closely.

[guenter]

imatfaal, on 29 December 2011 - 04:52 PM, said:

the CMBR footprint for antimatter/matter annihilation - how would we know?

imatfaal, the homogeneity of the CMB (the temperature variation is around 10^-5) originates from the thermal equilibrium of the plasma at that time. This excludes annihilation radiation areas.

[imatfaal]

guenter, on 29 December 2011 - 10:26 PM, said:

imatfaal, the homogeneity of the CMB (the temperature variation is around 10^-5) originates from the thermal equilibrium of the plasma at that time. This excludes annihilation radiation areas.

I see what you mean - but surely it only excludes annihilation areas that were localised enough and close enough in time to end of the scattering to not reach thermal equilibrium with surroundings, or are our measurements accurate enough to rule that out?

[guenter]

imatfaal, on 30 December 2011 - 10:58 AM, said:

... or are our measurements accurate enough to rule that out?

Sorry, to avoid misunderstanding: to rule what out?

[Sorcerer]

So NOT including dark matter, whatever that is (something that's postulated because our current model doesn't fit with observation).

If u tally all the mass of matter in the universe and all the mass of black holes, would it balance, eg all the black holes are made of mainly anti matter?

My take on the CMB is that photons were interacting at close proximity with electrons/positrons during and after any annihilation/decay AND/OR removal of positrons into black holes, this light was intense and throughout the compact universe. This continued untill the universe cooled down/expanded sufficiently to coelesce into atoms. The CMB is a redshifted image of this and smooth because of the super fast expansion of inflation.

Guenter when u say "the microwave background shows no signature of matter-antimatter annihilation", what do u mean? Surely the signature of this is photons and microwaves are photons. Please clarify.

[guenter]

Sorcerer, on 31 December 2011 - 06:43 AM, said:

Guenter when u say "the microwave background shows no signature of matter-antimatter annihilation", what do u mean? Surely the signature of this is photons and microwaves are photons. Please clarify.

Scorcerer, imagine the 3000 K proton-electron plasma being in thermal equilibrium with radiation (photons) 380000 years after the big bang. Now, after cooling by expansion protons and electrons combine to hydrogen atoms, there is no more charge scattering and the universe is transparent. After expansion of the universe we detect these photons at a temperature of 2.73 K. (The energy of photons can be expressed as wavelenght or frequency but also corresponds to a temperature).
Now imagine "islands" of antimatter plasma (antiprotons and positrons) here and there in the 3000 K plasma then. The unavoidable matter-antimatter annihilation would have created photons of much higher energy (>> 3000 K) and thus their temperature would exceed 2.73 K today by far. The CMB doesn't show such photons.

[granpa]

actually pair production and annihilation could explain why the cmb is such a uniform temp.

the highest temp the universe could ever have been is the temp at which pair production occurs.

there may have been a long period of time when the whole universe was at precisely that temp.

during that time matter and antimatter somehow became separated.

then when the universe expanded it cooled to below that temp and pair production ceased.

[guenter]

granpa, on 1 January 2012 - 07:19 AM, said:

actually pair production and annihilation could explain why the cmb is such a uniform temp.

No, annihilation creates gamma rays. That isn't observed.

Inspite of this there is no thermal equilibrium of matter/antimatter/radiation at temperartures less than GUT scale.

Happy new year to everybody!