B Current values for Friedman's scalar and its derivative?

[exmarine]

What are the current values for Friedman's scalar and its first derivative with respect to time?

Thanks.

 

[Orodruin]

Are you referring to the scale factor $a(t)$. It depends on your convention. A typical convention is to choose $a(t_0) = 1$, where $t_0$ is the current time. Its derivative is then directly given by the Hubble parameter $H_0 = \dot a(t_0)/a(t_0) = \dot a(t_0)$.

 

[exmarine]

Yes, what is the current value of the Hubble parameter? It should be some number per unit time?

 

[Orodruin]

http://lmgtfy.com/?q=hubble+constant+observed+value
We are not an encyclopaedia ...

 

[Arman777]

Yes, what is the current value of the Hubble parameter? It should be some number per unit time?

a(t) doesn't mean itself anything. The ratios of a(t) matters. Like a(t_0)/a(t_1)