The origin and evolution of the universe has always been one of the biggest mysteries of mankind, and scientists have tried to uncover the mysteries of the universe and restore the history of the universe through various methods and means. Sometimes, however, their findings contradict their theories and expectations, or even subvert their perceptions. That's why scientists occasionally encounter some facts that are difficult to explain when observing the sky. One of the most surprising facts is that scientists have discovered a star older than the universe. The star is called "Methuselah", and it is located 190 light-years away from the Earth, in the constellation Libra, and is a metal-poor subgiant, which means that it contains very little metal in its body, which is usually an important indicator of whether a star is old or not. Scientists have estimated its age to be about 16 billion years old by measuring its spectrum and distance, and this number is even older than the age of the universe! What's going on here? Could it be that this star was born outside the universe? Or is the age of the universe underestimated by us? This question has left scientists confused and arguing, trying to find a plausible explanation for this seemingly impossible contradiction.
To answer this question, we must first know how the age of the universe is determined. At present, the theory of the origin of the universe generally agreed by scientists is the "big ** theory", which believes that the universe starts from an extremely small, high-density, high-temperature state, and after a violent **, expands in all directions, forming the universe we see today. According to this theory, scientists can calculate the age of the universe by measuring the rate at which it is expanding. The expansion rate of the universe, also known as the Hubble constant, is a numerical value that describes how many kilometers the universe expands per megasecond of a minute. Scientists measure the Hubble constant by observing various celestial bodies in the universe, such as supernovae, galaxies, galaxy clusters, etc. They can then divide the Hubble constant by the acceleration of the universe to get the age of the universe. According to the latest measurements in 2013, the Hubble constant is about 674. The acceleration of the universe is about 07, then the age of the universe is about 138200 million years.
This result seems to be very accurate, but it is actually quite inaccurate. This is because different observation methods and data may obtain different Hubble constants, which will affect the calculation of the age of the universe. For example, in 2019, some scientists used the Hubble Space Telescope to observe some variable stars in the universe and got a larger Hubble constant of about 734, then the age of the universe will be shortened to 127400 million years. This difference, which is out of the margin of error, has left scientists confused as to which result is more reliable. Compared to the age of the universe, the age of a star seems to be easier to determine because the life cycle of a star is relatively stable and compatible. Scientists can determine the type, evolutionary stage, and age of a star by observing its spectra, brightness, mass, temperature, and other characteristics. In general, the more massive a star is, the shorter its lifespan will be, as it will consume its own nuclear fuel more quickly, eventually exploding into a supernova or collapsing into a neutron star or black hole. And the smaller the mass of the star, the longer its lifespan will be because it will burn its own nuclear fuel more slowly and eventually become a white dwarf or brown dwarf. Based on this principle, scientists can estimate the upper age limit for different types of stars.
For example, the Sun is an intermediate-mass star with an upper age of about 10 billion years, while it has been around for about 46 years at the moment500 million years, and about 53500 million years of life. The maximum mass star, such as the blue giant, has an upper age limit of only a few million years, while the lowest mass star, such as the red dwarf, can reach an upper age of trillions of years, or even more than the age of the universe. So, what type of star is "Methuselah"? How is its age determined? "Methuselah" is a metal-poor subgiant with a mass of about 08 solar masses, it has a brightness of about 06 solar brightness, its temperature is about 5600 Kelvin, which is slightly colder than the sun. Scientists have come up with an estimate of its age, which is about 16 billion years old, by measuring its spectrum and distance. This result is based on the assumption that "Methuselah" is a second-generation star, that is, it is composed of hydrogen and helium left behind after the death of the first-generation star, and the first-generation star is composed of the original material produced by the large **, without any metallic elements.
As a result, Methuselah has an extremely low metal content, only 250 times that of the Sun, which is why it is considered a very old star. The answer to this question is not simply to say that "Methuselah" is a star older than the universe, but to take into account the errors and uncertainties of measurement. First of all, we need to understand that measuring the age of both the universe and the age of stars is not an easy task and requires relying on some assumptions and models that may not be entirely accurate or applicable. Second, we need to know that the measured results have a certain margin of error, that is, the true value may fluctuate within an interval rather than a fixed number. Therefore, when we say that "Methuselah" is older than the universe, we are actually saying that its estimate is greater than the estimate of the universe, but this does not mean that its true age is necessarily greater than the true age of the universe, because their true ages may all be within their respective margin of error. So, why is this happening? Why is the estimate of "Methuselah" larger than the estimate of the universe?
There are several reasons for this: First, the age estimate of the universe is underestimated. This may be because we have incorrect measurements of the expansion rate and acceleration of the universe, or our theory of the origin and evolution of the universe is flawed. Secondly, the estimate of "Methuselah" is overestimated. This may be because we have incorrectly measured the spectrum and distance of Methuselah, or our theory of the type and evolution of stars has been flawed. Finally, the estimates of the universe and "Methuselah" were incorrect. This may be because we have inadequacies in our measurements and theories about the universe and stars, or we have misconceptions about the nature and relationship between the universe and stars.
In short, "Methuselah" is a very special star, and the mystery of its age makes us think more about the origin and evolution of the universe. It also reminds us that the mysteries of the universe are far beyond our imagination, and we still have a lot of unknowns and uncertainties that require us to constantly observe and verify in order to gradually get closer to the truth. Perhaps one day, we will find that the age of the universe and the age of the stars are not so important, but the important thing is that we can find our place and meaning in this universe. What do you think about this? Welcome to one-click three-in-a-row, that's all for this issue, thank you**, I'm exploring the universe, we'll see you next time.