Methuselah: a star older than the universe itself?
Can a star be older than the universe it belongs to? In the specific case can Methuselah (HD 140283), have an age of 16 billion years, when our universe should not exceed about 13.8 billion?
The answer is certainly negative unless you look for very imaginative solutions.
No star can be older than the universe
For instance HD 140283, better know as Methuselah, star of the Libra constellation located about 190 light-years from the Earth, whose composition shows very low percentages of metals such as iron (formed billions of years after the “Big Bang”), could be a “wreck” of a universe previous to ours that somehow survived in our universe.
But how would it have succeeded? No: whatever was there before the “Big Bang”, everything that currently exists in our universe can only be formed from that moment and therefore cannot be older.
The problem of correct estimation
The reality is that determining the age of a star is not easy: it is necessary to estimate as accurately as possible its brightness and the amount of oxygen inside it, in order to be able to estimate this star's age with sufficient accuracy.
The estimate of 16 billion years of age for HD 140283 was formulated by a team of researchers in 2000 using the observations data of the Hipparcus satellite of the European space agency (ESA).
The age drops from 16 to 14.27 billion years
Subsequent checks between 2003 and 2011, based on data collected by Hubble space telescope, reduced the estimated age of Methuselah to 14.46 billion years. A decidedly lower age but still higher than the 13.8 billion years of our universe.
Further research and studies followed and in 2014 the age of Methuselah was reduced again: 14.27 billion years, with an approximation between 700 and 800 million years.
Pay attention to the statistical error
At this point, Methuselah, which in fact is 188.54 more or less 1.52 light-years from Earth, could actually have 13.47-13.57 billion years compatible with about 13.8 billion years (to be precise 13.798 more or less 37 million years).
As mentioned, measuring the age of a star is not so simple, especially when dealing with cosmic sizes, accuracy is always relative, despite how many efforts and improvements can be made. The important thing is to realize it and continue to study the cosmos.