Determining Age of Universe Using Hubbles Constant

In summary, the age of the universe can be determined by using Hubble's Constant, which is a measure of the rate at which the universe is expanding. Depending on the model of the universe being used, the age can be calculated by applying formulas derived from the Friedmann equations of general relativity. For example, in a simple matter-dominated universe with zero cosmological constant, the age of the universe is equal to two-thirds of the reciprocal of the Hubble constant. By converting the value of the Hubble constant from km/sec/Mpc to 1/sec and taking the reciprocal, an estimate of the age of the universe can be obtained.
  • #1
radius
10
0
Please can somebody explain how the age of the universe can be determined using Hubbles Constant?
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!
 
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  • #2
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
 
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  • #3
age of universe

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


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.
 

What is Hubble's Constant?

Hubble's Constant, denoted as H0, is a value that represents the current rate at which the universe is expanding. It is named after astronomer Edwin Hubble who first measured and described this phenomenon.

How is Hubble's Constant used to determine the age of the universe?

Hubble's Constant is used in conjunction with other measurements, such as the cosmic microwave background radiation, to calculate the age of the universe. This is done by using the equation t=1/H0, where t represents the age of the universe and H0 is the current value of Hubble's Constant.

What is the current estimated age of the universe?

Based on recent observations and calculations, the current estimated age of the universe is approximately 13.8 billion years. This is subject to change as new data and technology become available.

How accurate is the estimated age of the universe using Hubble's Constant?

The estimated age of the universe using Hubble's Constant is subject to uncertainties and can vary depending on the methods and data used. However, it is generally accepted to be accurate within a few hundred million years.

Can Hubble's Constant change over time?

Yes, Hubble's Constant is not a constant value and can change over time. It is affected by various factors such as the density of matter in the universe and the expansion rate. Therefore, it is important for scientists to continue to make observations and measurements to refine our understanding of Hubble's Constant and the age of the universe.

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