75+/-25km*s^-1*Mpc^-1: parabolic, hyperbolic, or elliptical?

[fafalone]

Under current assumptions of the universe,

__..

q=RR/.R²=(4*pi*kappa*d)/3H²

 

where H is Hubble's constant, d is the density of the universe, and W is the amount of energy in the universe, we have 3 possible outcomes:

 

k, W = 0, q=1/2... rate of expansion -> 0 | t->:inf:

 

k=-1, W<0, q<1/2... rate > 0 forever.

 

k=1, W>0, q>1/2... big crunch

 

 

What I wish to discuss is possible ways to measure H, either through observation or equating terms with other equations. Also, I'm not sure why we can get the possible value somewhere within 25 of 75 but not closer, anyone care to enlighten me?

[KHinfcube22]

The only way to know as one's self what will happen, or what is happening, to the universe is to either ask an alien being who has lived for millieniums, or find a way to prolong life. Now the the first one will be not easy, but the seconds child's play.

[Skye]

Interesting question, and not one I'd really read much about (I'm not really into astrophysics).

 

The differences seem to occur when comparing different methods of calculating the Hubble constant. Estimates using the same method seem to agree, at least from the little I've read.

 

Using Cepheid variables (young stars which have a fairly constantly fluctuating luminosity which allows their absolute luminosity to estimated) the Hubble constant has been estimated at 83 +/- 13 and 81 +/- 8. Using supernovae it's estimated at 57 +/- 4. From this site. Using the Sunyaev-Zel'dovich effect (don't ask me to even attempt to explain it) H is estimated at 38 +17/-12 and 47 +18/-12. From this site.

 

Given that each method obtains similar results, the error would seem to be in some factor that accounts for the variation between the methods.