When we scientifically think of the question “How did everything come into being?”, most of us think of the Big Bang theory, because it has been one of the most plausible and well-supported theories regarding the beginning of the time and universe. The history of Big Bang theory goes back to the 1920s when Georges Lemaître proposed an expanding model for the universe in order to explain the observed redshifts of spiral nebulae and calculate the Hubble law. He based his theory on the work of Einstein and De Sitter, and then independently derived Friedmann’s equations for an expanding universe. The theory has been well-supported and widely accepted by the majority of scientific and non-scientific communities. However, a research published in 2019 shocked the world by maintaining that the theory may be disproved with the age estimation of the “Methuselah” star.
HD 140283 – or as commonly known, Methuselah star has been observed by astronomers for more than 100 years. It is said to be one of the universe’s oldest stars, located in the Libra constellation around 190 light years away from Earth. Methuselah rapidly journeys across the sky at 1.3 million kilometers / hour. Since the beginning of the 20th century, a group of scientists have tried to observe the star via European Space Agency’s (ESA) Hipparvos satellite, estimating the age of the star to be 16 billion years old – this has been a shock to the scientific community, since the age of the universe, determined from observations of the cosmic microwave background, is estimated to be 13.8 billion years. How could a star, produced by the Big Bang, be older than the age of the universe? According to an online statement, “it was certainly clear that Methuselah – named in reference to a biblical patriarch who is said to have died aged 969, making him the longest lived of all the figures in the Bible – was old, since the metal-poor subgiant is predominantly made of hydrogen and helium and contains very little iron. Its composition meant that the star must have come into being before iron became commonplace. But more than two billion years older than its environment? Surely that is just not possible.”
According to researches, Methuselah star, now bloating into a red giant, was probably born in a dwarf galaxy that nascent Milky Way gobbled up more than 12 billion years ago.
Using the principle of parallax, Hubble’s measurements allowed astronomers to refine the distance to Methuselah in which a change in observers’ position – in this case, Hubble’s varying position in Earth orbit – translates into a shift in the apparent position of an object. They found that Methuselah is located around 190.1 light years away. With the star’s distant more precisely, the team was able to figure out Methuselah’s intrinsic brightness, a necessity for determining its age. Furthermore, scientists applied the current theory to learn more about the star’s burn rate, composition, and internal structure, shedding light on its likely age.
To conclude, a new study published in the Astrophysical Journal Letters stated that astronomers estimated the age of Methuselah to be 14.5 billion years old, plus or minus 800 million years. Further observations could help in bringing the age of Methuselah star down even further. However, 14.5 billion years still makes the star older than the age of the universe which is estimated to be 13.8 billion years.
However, whether this old star’s age is accurate or not remains a mystery for now – nevertheless, further study of this star shall either provide further pieces of evidence for the theory of the Big Bang, or bring a dramatic fall to one of the most plausible and groundbreaking scientific theories.