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How can a star be older than the universe?

For over 100 years, astronomers have observed a curious star located about 190 light-years from Earth in the constellation Libra. Fast travels through the sky at 800,000 miles per hour (1.3 million miles per hour). But more interesting than that is that HD 140283 – or Methuselah, as it is known – is also one of the oldest known stars in the universe.

In 2000, scientists tried to date the star through observations through the satellite of the European Space Agency (ESA) Hyparkos, which estimated the age of 16 billion years. Such a figure was quite mind-blowing and also quite puzzling. As the astronomer Howard Bond of Pennsylvania State University pointed out, the age of the universe ̵

1; as determined by observations from the cosmic microwave background – is 13.8 billion years old. "It was a serious discrepancy," he said.

Related: Methuselah Star: The Oldest Famous Star Revealed (Gallery)

Taken at face value, the estimated age of the star raised a Major Problem. How can a star be older than the universe? Or, conversely, how can the universe be younger? It was certainly clear that Methuselah – named in connection with a biblical patriarch who was said to have died at the age of 969, which made him the longest lived of all figures in the Bible – was old because he was growing up with It is mainly made of hydrogen and helium and contains very little iron. Its composition meant that the star must have arisen before iron became commonplace.

But more than two billion years older than your environment? Certainly this is simply not possible.

A closer look at the Methuselah era

Bond and his colleagues set themselves the task of determining whether or not this initial figure of 16 billion was. They compared more than 11 sets of observations recorded between 2003 and 2011 by the Hubble Space Telescope's Fine Orientation Sensors, which capture the positions, distances and energy output of stars. When receiving parallax, spectroscopy and photometry, a better sense of age can be determined.

"One of the uncertainties with the age of HD 140283 was the exact distance of the star," Bond told All About Space. "It was important to rectify this because we could better determine its luminosity and from that its age – the brighter the inner luminosity, the younger the star. We were looking for the parallax effect, which meant we were looking at star six months apart from looking for a change in position due to the orbital motion of the Earth, which tells us the distance. "

There was also uncertainty in the theoretical modeling of the stars, such as the exact rates of nuclear reactions in the nucleus and the importance of the elements that diverge down in in nshnite layers, he said. They worked on the idea that residual helium diffuses deeper into the nucleus, leaving less hydrogen to burn through nuclear fusion. When fuel is used faster, age decreases.

This is the backyard to the sky around the ancient star, cataloged as HD 140283, located 190.1 light-years from Earth. The star is the oldest known to astronomers to date.

(Photo: A. Fujii and Z. Levay (STScI))

"Another important factor was that of all things, the amount of oxygen in the star," Bond said. HD 140283 has a higher than predicted oxygen-to-iron ratio, and since oxygen has not been abundant in the universe for several million years, it again indicates a lower age for the star.

Bond and his associates estimate the age of HD 140283 at 14.46 billion years – a significant decrease from the 16 billion previously claimed. However, this was more than the age of the universe itself, but scientists created residual uncertainty of 800 million years, which Bond said the star's age was compatible with the age of the universe, though not completely perfect.

Related: Star Quiz: Test your Stellar Smarts

"Like all measured estimates, it is subject to both accidental and systematic errors," says physicist Robert Matthews of the University in Aston, Birmingham, United Kingdom, who did not participate in the study. "The overlap in the error bars gives some indication of the likelihood of a collision with cosmological determinations of age," Mathews said. "In other words, the best-supported star era is in conflict with that of the derivative era of the universe [as determined by the cosmic microwave background]. Conflict can only be resolved by pushing the error bars to their extreme limits."

In addition, the specs saw the age of HD 140283 drop a little more. A 2014 follow-up survey updates the star's age to 14.27 billion years. "The conclusion is that age is about 14 billion years and again, if one includes all sources of uncertainty – both in observation and theoretical modeling – the error is about 700 or 800 million years, so there is no conflict because 13.8 billion years are in the star's fault line, "Bond said.

Scientists wanted to find out when the universe began
– that is, when the Big Bang came and left its imprint on the fabric of the cosmos.

(Image Credit: NASA) [19659023] Take a closer look at the Age of the Universe

For Bond, the similarities between the Age of the Universe and that of this old nearby star – both determined by different methods of analysis – is "an incredible scientific achievement that provides very strong evidence for the Big Bang picture of the universe. "He said that the problem of the age of the oldest stars was far less severe than in the 1990s, when the star age was approaching 18 billion years or, in one case, 20 billion. years. "With the uncertainty of definitions, the ages now agree," Bond said.

Nevertheless, Mathews believes that the problem has not yet been resolved. Astronomers at an international conference of top cosmologists at the Cavle Institute of Theoretical Physics in Santa Barbara, California, in July 2019, puzzled studies that suggested ages of different ages for the universe. They looked at measurements of galaxies that are relatively close, suggesting that the universe is younger by hundreds of millions of years compared to the age determined by the cosmic microwave background.

Related: Big Bang to Civilization: 10 Incredible Events of Origin

In fact, far from 13.8 billion years, according to calculations of the detailed measurements of the cosmic radiation of the Plane Space Telescope in 2013, the universe could be barely 11.4 billion years old. One of the people behind the research is the Nobel laureate Adam Riess of the Space Telescope Science Institute in Baltimore, Maryland.

The conclusions are based on the idea of ​​an expanding universe, as demonstrated in 1929 by Edwin Hubble. This is fundamental to the Big Bang – the understanding that there once was a state of hot density that erupted outward, extending into space. It shows a starting point that needs to be measurable, but fresh findings suggest that the expansion rate is actually about 10% higher than what Planck suggested.

In fact, Planck's team determined that the rate of expansion was 67.4 km per second per megaparsec, but more recent measurements of the rate of expansion of the universe indicate values ​​of 73 or 74. This means that there is a difference between measuring this how fast the universe is expanding today and projections for how fast it should expand based on the physics of the early universe, Ries said. This leads to a reassessment of accepted theories, while showing that there is much more to learn about the dark matter and dark energy that are thought to be hiding behind this puzzle.

Related: The 11 Biggest Unanswered Questions for Dark Matter

Higher Hubble Value Indicates A Shorter Age for the Universe. A constant of 67.74 km per second per megaparsec would lead to an age of 13.8 billion years, while one of 73, or even over 77, as some studies indicate would indicate an age of the universe no greater than 12.7 billion years. This is a mismatch, again suggesting that HD 140283 is older than the universe. It has since been replaced by a 2019 study published in the journal Science, which suggested a Hubble constant of 82.4 – suggesting that the age of the universe is only 11.4 billion years.

Mathews believes that the answers lie in greater cosmological refinement. "I suspect observational cosmologists have missed something that creates this paradox, not stellar astrophysicists," he said, pointing out that the measurements of the stars are perhaps more accurate. "Not because cosmologists are somehow weaker, but because the age determination of the universe is subject to more and arguably more rigorous observational and theoretical uncertainties than stars."

Nebula and stars in deep space.

(Image Credit: Vadim Sadovsky / Shutterstock)

So how will scientists understand this?

What could make the universe look younger than this particular star?

"There are two variants and the history of science suggests that in such cases, reality is a mixture of the two," says Mathews. "In this case, these would be sources of observational error that are not fully understood, plus some flaws in the theory of the dynamics of the universe, such as the power of dark energy, which has been the main engine of space expansion for many billions of years." [19659002] Related: Dark Matter and Dark Energy: The Mystery Explained (infographic)

It suggests that the present "age paradox" reflects the time change of dark energy and thus changes in the speed of darkness. acceleration – probability theorists have discovered that it may be compatible with ideas about the fundamental nature of gravity, such as the so-called cause-effect theory. New studies of gravity waves can help resolve the paradox, Mathews said.

To do this, scientists would look at the waves in the fabric of space and time created by pairs of dead stars instead of relying on cosmic microwave backgrounds or monitoring nearby objects, such as Cepheid variables and X-ray superstructures – the first resulted in a speed of 67 km per second per megaparsec and the second in 73.

The problem is that measuring gravitational waves is not an easy task, given that they were only detected directly for the first time through 2015 But according to Stephen Feeney, strofizik Institute Flatiron in New York can make a breakthrough in the next decade. The idea is to collect data from collisions between pairs of neutron stars, using the visible light that these events emit to understand the speed they are moving toward Earth. This also includes an analysis of the gravitational waves obtained for the distance idea – both of which can be combined to give a Hubble Constant measurement, which should be the most accurate so far.

The mystery of the era of HD 140283 leads to something bigger and more scientifically sophisticated, changing the understanding of how the universe works.

"The most likely explanation for the paradox is some neglected observational effect and / or something that is missing from our understanding of the dynamics of space expansion," Mathews says. Exactly what this "thing" is, remember that astronomers will be challenged for some time.

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(Credit image: Future plc)

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