- #1

radius

- 10

- 0

If the constant is taken as 10km/s (just for the sake of easiness), how can this be figured out using calculations?

I appreciate any help!

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter radius
- Start date

- #1

radius

- 10

- 0

If the constant is taken as 10km/s (just for the sake of easiness), how can this be figured out using calculations?

I appreciate any help!

- #2

Ambitwistor

- 841

- 1

It depends on which model of the universe you're using. e.g., if you take a simple matter-dominated Friedmann cosmology with zero cosmological constant, you end up with the age of the universe equalling two-thirds of the reciprocal of the Hubble constant. You work out formulas from this from the Friedmann equations for the evolution of such a universe (which are in turn derived from the Einstein field equation of general relativity). See, for example:

http://itss.raytheon.com/cafe/qadir/q1626.html

http://itss.raytheon.com/cafe/qadir/q1626.html

Last edited by a moderator:

- #3

radius

- 10

- 0

Thankyou for your help but what you gave me is a bit over my head.

"I have been given the task the Hubble constant is thought to be in the range 10 - 20 km/sec ^-1.

What age range does this imply for the universe?"

I am not sure where to begin...

- #4

Ambitwistor

- 841

- 1

Convert the value for the Hubble constant from km/sec/Mpc to 1/sec, and take the reciprocal. That will be roughly close to the age of the universe (in seconds); you can multiply by 2/3 if you want a Friedmann matter-dominated universe with zero cosmological constant, or multiply by some other factor if you want a different model.

Share:

- Replies
- 5

- Views
- 686

- Replies
- 6

- Views
- 613

- Replies
- 2

- Views
- 327

- Replies
- 19

- Views
- 633

- Replies
- 2

- Views
- 605

- Last Post

- Replies
- 17

- Views
- 612

- Last Post

- Replies
- 4

- Views
- 427

- Replies
- 12

- Views
- 857

- Replies
- 13

- Views
- 1K

- Replies
- 82

- Views
- 4K