Astronomy

How old our universe is? So far, astronomers had applied several methods to determine the age of the universe. One method is by estimating age of element on our Milky Way galaxy based on radioactive decay of element that its half-period is already known, and then, assumed that the elements created (on a giant star supernovae) in steady speed. Based on this method, the age of our universe is presumed around 14.3 ± 3 billion years.

Another method is by measuring age of any star clusters, based on assumption about dynamic and distance of the clusters. Oldest clusters suppose to be as old as 11.5 ± 1.3 billion years, so the age of universe is around 11 to 14 billion years.

By extrapolating velocity of expansion of the universe, and the distance to furthest object, we get the number of 13 to 14 billion years. Unfortunately, latest discovery shows that expansion of the universe is accelerating, and it makes this prediction to be uncertain.

Latterly, complete self-supporting method has been completed. Hubble Space Telescope, which had been working nearly at the edge of its capability, has measured temperature of some oldest white-dwarf star on M4 globular cluster. This technique is analogue to measuring when the fire starts burning based on its coal’s temperature. With this method, we know that the oldest white-dwarf stars aged 12 to 13 billion years. By assumed that first stars formed less than 1 billion years after the big bang, then we get the age of the whole universe is in between 13 to 14 billion years.

Estimate which now assumed as most accurate obtained on February 2003 by Wilkinson Microwave Anisotropy Probe (WMAP). Pursuant to obtained data, age of universe is estimated by about 13.7 ± 0.2 billion years.

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