Current value of the scale factor(R₀)?

[EhsanZ]

What is the current value of the scale factor(R₀)?

a= R(t)/R₀

Give me the number.

 

[Simon Bridge]

R₀ is the value of R(t) at t=0.
Apart from that, need more information.

 

[e.bar.goum]

Since a = R(t)/R₀, and we normalise to the current epoch, right now, R(t) = R₀

 

[Simon Bridge]

<headslap> cosmology forum!

 

[e.bar.goum]

Sorry, is that directed at me?

 

[Simon Bridge]

No - I don't slap anyone elses head unless there is some sort of contractual obligation.
See post #2 ... mumble mumble I suppose had I shut up people would think I was being clever?

 

[EhsanZ]

Since a = R(t)/R₀, and we normalise to the current epoch, right now, R(t) = R₀

Number?

 

[e.bar.goum]

It's a scaling factor, there isn't one. Maybe if you be more specific with your problem, we can help you. You can arbitrarily change it depending on your cosmology.

 

[George Jones]

If the universe is not (spatially) flat, then

$$R_0 = \frac{c}{H_0} \sqrt{\frac{k}{\Omega_{m,0} + \Omega_{r,0} + \Omega_{\Lambda,0} - 1}}.$$
If the universe is (spatially) flat, then $R_0$ is arbitrary.