You are invited to Log in or Register a free Frihost Account!

# Cosmological constant and expanding universe

yagnyavalkya
A positive value for the consmologial constant was found by the studies of Adam G. Riess et al and Pearlmutter et al
In terms of Planck units, and as a natural dimensionless value, the cosmological constant, λ, is on the order of 10−122 or 10−29 g/cm3
The cosmological constant has negative pressure equal to its energy density and so causes the expansion of the universe to accelerate.
The universe is accelerating and space is expanding
Does it mean that new space is being created and if so what is the cosmological constant in the new space or expanded space
If suppose an area of space has a cosmological constant value of 10−29 g/cm3 then if it expands what will be the value of consmological constant as the word itself says it is constant
Is dark ernegy or dark matte crearted to keep this constant
Bikerman
New space IS created and that new space will have the same CC (IF this theory is correct).
That will, obviously, lead to an increase in the rate of expansion which would be exponential I believe.
yagnyavalkya
 Bikerman wrote: New space IS created and that new space will have the same CC (IF this theory is correct). That will, obviously, lead to an increase in the rate of expansion which would be exponential I believe.

If the new space has the same CC then where does the new dark matter come from is it also created
Bikerman
What new dark matter?
yagnyavalkya
 Bikerman wrote: What new dark matter?

Cosmological costant is some matter or is it not because the unit is g/cm3 then where does the new space get CC from I mean the newly created space when expanding should also have a CC and the unit is g/cm3 where does this CC come from
Bikerman
No. CC is the pressure of empty space. The tensor is dimensionless. I suspect the g/cm^3 is just a convenient way of expressing the energy - as mass rather than another unit. e=mc^2
yagnyavalkya
 Bikerman wrote: No. CC is the pressure of empty space. The tensor is dimensionless. I suspect the g/cm^3 is just a convenient way of expressing the energy - as mass rather than another unit. e=mc^2

even then if spaces streches or expands how is the CC kept constant
Bikerman
Why would it not be? It is a measure of the pressure per unit volume of space.
yagnyavalkya
 Bikerman wrote: Why would it not be? It is a measure of the pressure per unit volume of space.

If it is 'pressure per unit volume of space" and space is expanding then the volume of space is increaseing then the pressure must decrese how is "pressure per unit volume of space" kept constant when the volume of space is increasing
Bikerman
Why must pressure decrease?
Pressure PER UNIT VOLUME OF SPACE.
More space means more pressure OVERALL, but the unit pressure remains constant.
yagnyavalkya
 Bikerman wrote: Why must pressure decrease? Pressure PER UNIT VOLUME OF SPACE. More space means more pressure OVERALL, but the unit pressure remains constant.

More space comes from expansion where does more pressure come from
Bikerman
yagnyavalkya wrote:
 Bikerman wrote: Why must pressure decrease? Pressure PER UNIT VOLUME OF SPACE. More space means more pressure OVERALL, but the unit pressure remains constant.

More space comes from expansion where does more pressure come from

In the Cosmological Constant model of the universe, the pressure is a property of 'empty' space - it is intrinsic and doesn't 'come' from anywhere.

FRIHOST HOME | FAQ | TOS | ABOUT US | CONTACT US | SITE MAP
© 2005-2011 Frihost, forums powered by phpBB.