Scientists have calculated that our Sun is about 4.57 billion years old. So how can they know that?

Nuclear radioactivity calculation

The technique scientists use is called nucleocosmochronology. This method uses nuclear radioactivity to determine the age of all planets and objects that exist in space.

Scientists will look for isotopes produced by radioactive decay of unstable elements. An example is iron-60, an isotope of iron with 60 protons and neutrons in its core. Generating iron-60 is extremely difficult and is usually produced only in shock waves found after supernova explosions, which occur when a star is born. After only a few million years, iron-60 becomes unstable and decays into nickel-60, which is stable and lasts forever.

Scientists have found nickel-60 scattered throughout the solar system, especially inside meteorites left over from the formation of the solar system. By measuring the amount of nickel-60, astronomers can go back in time by calculating the half-life, figuring out when the solar system was full of iron-60.

Scientists calculate radioisotopes to find out the age of the Sun.

The cycle of the star

Another approach to measuring the age of the Sun involves understanding the life cycles of the stars. Stars are so long-lived that we cannot track a single star during its lifetime. But we see billions and billions of stars around us. Some stars were born recently, while others were born long ago. So scientists will take different pictures of their life cycle to trace their life cycle.

By studying millions of stars and applying knowledge of physics (especially nuclear fusion in stellar cores), astronomers have created a kind of map: if you give If a star has a specific mass and luminosity, they can estimate its age. When they applied this map to our Sun, the scientists still got the same answer as they did when they measured radionuclides and found that the Sun was just over four and a half billion years old. .

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