For over 100 years, astronomers have been observing HD 140283, a star from the constellation of Libra, about 200 light-years away from us. The celestial body moves at a speed of 1.3 million kilometers per hour, but more importantly, HD 140283 (Methuselah) is the oldest known star in the universe.
In 2000, researchers determined the age of HD 140283 using Hipparcos, a satellite of the European Space Agency (ESA). The device discovered that the star appeared more than 16 billion years ago. This figure is unbelievable, because the age of the universe, according to Howard Bond, an astronomer at the University of Pennsylvania, is 13.8 billion years old, and it is derived from relic electromagnetic radiation.
If Hipparcos indication is correct, then the question arises: how can a star be older than the Universe?
The star is named after biblical character Methuselah, who was one of the forefathers of mankind and the ancestor of Noah. He is the oldest person listed in the Bible.
The star consists mainly of hydrogen and helium, and also contains an insignificant amount of metals. Its composition tells us that the appearance of a cosmic body should have preceded the spread of iron.
However, this study leads to a paradox: Methuselah is more than 2 billion years older than its environment! Of course, this is simply not possible.
Howard Bond and his colleagues collected more than 11 sets of observations from 2003 to 2011 to confirm the initial data on the age of the star. The information was obtained from the Hubble telescope and its sensors of the precision guidance system, recording the position, energy release and distance to stars. Using parallax data, spectroscopy and photometry, one can more accurately determine the age of the object.
Bond said: “One of the uncertainties with the age of HD 140283 was the precise distance of the star.” He added that determining the distance from Methuselah is important for studying the stellar magnitude and determining the age.
Visible magnitude is a measure of the brightness of a celestial body (star, galaxy, or even planet) from the point of view of an earth observer. The absolute magnitude, in turn, characterizes the luminosity of an astronomical body: this indicator has different definitions for various types of objects under study. For example, for stars, it is defined as the apparent magnitude of an object if it were located at a distance of 10 parsecs from the observer.
Other important elements of the study of Methuselah, according to Bond, were the parallax effect and analysis of the amount of oxygen in the star. Six months later, his team estimated the age of HD 140283 to be 14.46 billion years old, which is still more than the age of the universe.
The 2014 study again calculated the HD 140283’s age, this time to 14.27 billion years. According to Howard Bond, if someone gives all the uncertainties in the study, the error will be about 700 or 800 million years. It follows that the age of the star fits into the framework of 13.8 billion years, thereby resolving the conflict of the “star that appeared before the universe.” The scientist is convinced that this is one of the evidence of the Big Bang theory.
According to Bond, the determination of stellar age is now not as problematic as in the 1990s. Previously, according to research, it had been reaching to 18 or even 20 billion years.
Nevertheless, not all doubts are dispelled: many researchers believe that the Universe may be younger than 13.8 billion years. According to the European Planck space telescope‘s detailed measurements on cosmic radiations, the universe can only be 11.4 billion years old.
The findings are based on the idea of an expanding universe put forward by Edwin Hubble in 1929. The Planck team has identified an expansion rate of 67.4 kilometers per megaparsec (Mpc), but recent studies have revealed that the actual expansion rate is 10% higher and equal to 73-74 km / Mpc. Based on these data, it follows that the Universe is no more than 12.7 billion years old, which again indicates that HD 140283 “Methuselah” is older than its habitat.
According to Robert Matthews, a physicist from Aston University, the current “age paradox” grows out of a change in dark energy and acceleration speed over time. This paradox can be resolved with the help of new studies into gravitational waves, however, there is also a snag here: the waves themselves were discovered only in 2015.
Despite the complexity of this task, a breakthrough can be made in the coming decade. Stephen Feeney, an astrophysicist at the Flatiron Institute in New York, said that it is possible to collect data on collisions of pairs of neutron stars. For this, scientists need to use the electromagnetic spectrum to determine the speed of their motion relative to the Earth. Next, an analysis of the emerging gravitational waves is required to determine the distance. The total data will give the most accurate Hubble cons