{"id":478041,"date":"2025-01-19T22:46:10","date_gmt":"2025-01-19T20:46:10","guid":{"rendered":"https:\/\/osr.org\/?p=478041"},"modified":"2025-03-06T13:04:31","modified_gmt":"2025-03-06T11:04:31","slug":"why-do-stars-shine-a-journey-inside-a-stellar-core","status":"publish","type":"post","link":"https:\/\/osr.org\/en-uk\/blog\/astronomy-uk\/why-do-stars-shine-a-journey-inside-a-stellar-core\/","title":{"rendered":"Why Do Stars Shine? A Journey Inside a Stellar Core"},"content":{"rendered":"

When we gaze at the night sky, we see countless points of light twinkling across the vast expanse of space. But have you ever wondered – why do<\/em> stars shine? The answer lies in the heart of a star \u2013 its stellar core. Let\u2019s dive into the fascinating science behind the inner workings of stars and uncover the secrets of their brilliance.<\/span><\/p>\n

What Are Stars Made Of?<\/span><\/h2>\n

\"Why<\/p>\n

Stars<\/a> are massive celestial bodies composed primarily of hydrogen and helium, the two lightest and most abundant elements in the universe. These gases are pulled together by the immense force of gravity, forming a fiery sphere of plasma<\/a>. Hydrogen, the simplest and most abundant element, serves as the primary fuel for stars, while helium is produced as a byproduct of nuclear fusion.<\/span><\/p>\n

The composition of stars evolves as they age. Main sequence stars, like our Sun, consist mainly of hydrogen with a smaller proportion of helium and trace amounts of heavier elements such as carbon, oxygen, and nitrogen. As stars progress through their lifecycles, they begin to synthesise heavier elements in their cores, enriching their composition with materials like iron, silicon, and magnesium. These changes mark different stages in a star\u2019s evolution and influence its ultimate fate.<\/span><\/p>\n

The Stellar Core: Where the Magic Happens<\/span><\/h3>\n

At the centre of every star lies its core, an extraordinary region of intense heat and pressure. This is the powerhouse of the star, where temperatures soar to millions of degrees Celsius. For example, in a star like our Sun, the core reaches temperatures of around 15 million degrees Celsius. In more massive stars, the core can exceed 100 million degrees Celsius. This extreme environment sets the stage for nuclear fusion, the process that powers stars.<\/span><\/p>\n

The Lifecycle of a Star<\/span><\/h2>\n
\"Lifecycle

CREDIT: NASA's James Webb Space Telescope from Greenbelt, MD, USA<\/a>, CC BY 2.0<\/a>, via Wikimedia Commons<\/p><\/figure> CREDIT: NASA’s James Webb Space Telescope from Greenbelt, MD, USA<\/a>, CC BY 2.0<\/a>, via Wikimedia Commons<\/p><\/div>\n

Stars are born from vast clouds of gas and dust known as nebulae. Over time, gravity pulls these materials together, forming a dense region called a protostar. As the protostar grows in mass, its core heats up, and once the conditions are right, nuclear fusion begins. At this point, the star enters its main sequence phase, where it spends the majority of its life converting hydrogen into helium.<\/span><\/p>\n

As stars exhaust their hydrogen fuel, their fate depends on their mass. Smaller stars, like our Sun, expand into red giants as their outer layers swell. Eventually, these stars shed their outer layers, creating beautiful planetary nebulae, while their cores contract into dense white dwarfs. Larger stars undergo more dramatic endings. When their fuel runs out, they explode in spectacular supernovae<\/a>, leaving behind dense neutron stars or even black holes. Each stage of a star\u2019s lifecycle contributes to the cosmic recycling of elements, seeding the universe with materials for new stars and planets.<\/span><\/p>\n

Why Do Stars Shine? The Role of Nuclear Fusion<\/span><\/h2>\n
https:\/\/youtu.be\/W1ZQ4JBv3-Y?si=yLn5zIvhKnzCNTf7<\/a>