Is there anyone who does not admire the sparkle of stars on a clear night sky?Stars, undoubtedly, are the most recognized celestial objects. Gazing at the stars can be a fascinating experience that puzzles the inquisitive mind; have you ever wondered how are stars born?Stars may appear like tiny glitters in the dark sky, but they are actually enormous bodies of gas and dust in space, which are held by gravity. The hot burning matter is called plasma.Made of hydrogen and helium mostly, these luminous bodies emit heat and light. The nuclear fusion in the core of the stars makes them the source of heat and light. Most of us know that the sun is our closest star, and because of its closeness to our earth, the sun appears larger.However, most stars are much larger than the sun. They appear as tiny light spots on the sky even though they are several lightyears away from the earth. Stars are uncountable in number. The actual number of stars is not known. However, scientists estimate there are billions of stars in the universe. When several million stars hold on due to gravity, they make up a galaxy. The sun, our nearest star, is a member of the Milky Way galaxy. Apart from the sun, there are billions of stars in the Milky Way galaxy.Read ahead for more facts about stars. If you enjoy these exciting star facts, you would love our fun facts articles on how long for duck eggs to hatch? And how many legs does a centipede have? Make sure to check out these informative articles.The Life Cycle Of A StarIn a way, stars are similar to humans. Stars are born, they live, evolve, and eventually die. The life cycle of stars happens in a much more elaborate and spectacular manner. Stars are born out of an accumulation of dust and gas. The huge gas cloud from which the star formation happens is called a nebula. The Orion Nebula in the Milky Way galaxy, a bright nebula, can be seen with the naked eye in the night sky.From the time a star is born out of a nebula until it runs out of energy and dies, it undergoes several changes. The study of the changes in a star’s life over time is called stellar evolution.A star begins its life from a nebula; it then becomes a main-sequence star, and later on a red giant. The later stages depend on the mass of the star. Smaller stars, such as the sun, undergo a peaceful death passing through the stages of the planetary nebula to become a white dwarf. They later stop glowing and become a black dwarf. On the other hand, massive stars undergo a violent death. They turn out to become red supergiant stars and later scatter with an enormous supernova explosion which clears the gas and dust off. After the dust and gas particles are cleared off, they are left with a smaller and denser ball called a neutron star. A much larger red giant leaves a black hole behind mainly because the gravity is extremely powerful, collapsing the protons and neutrons.New stars continue arising from the debris and dust the supernovae leave. These make up the building blocks of new stars. The birth of new stars takes the lifecycle of stars forward. Thus, stars begin their life cycle in the gas and dust and end up in gas and dust.What are stars made of?Stars are amazing astronomical bodies. Innumerable stars glow in space. Do they emit light? What makes them glow? What are they made of? Well, the answers will surely interest you.Stars are astronomical bodies made mostly of gases such as hydrogen and helium. The hot matter that makes up a star is called plasma. Stars form out of clouds of gas and dust in interstellar space, called the nebula. Within the star, the vast amount of hydrogen constantly undergoes nuclear reactions. These reactions change hydrogen to helium which releases an enormous amount of energy.The mass of stars creates gravity, which keeps the planet in orbit around them. The sun’s gravity holds the planets in the solar system in orbit around it. Massive stars have high gravity. The sun’s mass is about 332,950 times the mass of the Earth.The lifespan of massive stars is shorter. For example, Eta Carinae, which is about 100-150 times more massive than the sun, will exist only several million years.Stars differ in their sizes. Some stars are just a few miles wide, while supergiant stars can be more than a thousand times larger than the sun. A neutron star, which is just around 12 miles (11.9 km) wide, is the smallest star. Neutron stars are considered dead stars. They have a tremendous amount of matter in a tiny space. UY Scuti, the hypergiant star, is the largest known star. Its radius is 1,700 times more than that of the sun.A star’s lifespan can be as long a several billion years. Most stars in the universe are about a billion to 10 billion years old. HD 140283 or the Methuselah star, the oldest star discovered, is more than 14 billion years old. How are stars created?Star formation is a spectacular process. A star’s formation begins from space regions of higher matter density, called molecular clouds. The molecular clouds consist of hydrogen, helium, and a few heavier elements. The dust and gas clouds that give birth to stars are called nebulae.A molecular cloud in interstellar space is enormous. This enormity causes the cloud to have turbulent movements, causing the gas and dust particles to move in all directions, distributing the molecules and atoms unevenly. This uneven distribution causes the accumulation of gas and dust in the clouds, leading to high gravity that collapses the regions. Stars form due to this gravitational collapse of matter.When these clouds of gas and dust collapse and shrink under the gravitational pull, they form clumps of dense material. The swirling clumps get hotter and denser and eventually begin with nuclear reactions. The hot core of these clumps gathers more and more gas and dust and forms a protostar. A protostar is a young star that continues to gather material from the molecular cloud. The stellar evolution begins with the protostar stage. The heat from nuclear fusion in its core inflates it; the material that falls in the core leads to star formation. When the temperature of the protostar’s core reaches over 10 million K, it becomes a main-sequence star. Most stars in the universe, including the sun in the solar system, are called main-sequence stars.The young star has a lower temperature than that of a star. If the mass of the protostar is less than 0.08 times the mass of the sun, the core does not reach the temperature enough for nuclear fusion to happen. In such cases, it remains a brown dwarf.The core of the main sequence star continues to fuse hydrogen atoms and form helium atoms. The mass of the main sequence stars can vary. They can be as less as one-tenth of the sun’s mass or as massive as around 200 times the mass of the sun.The mass of a star decides its lifespan. The less massive the star is, the longer its lifespan and vice versa. The lifetime of a star can be anywhere between a few million years to trillions of years. How do stars die?The gravitational pull in the gas cloud nebula causes it to heat up. The nuclear fusion in the core of a protostar releases abundant energy, changing hydrogen to helium. Eventually, in this process, main sequence stars form. Astronomers believe that most of the stars in the universe are main-sequence stars. These stars may continue to remain in the same stage for billions of years.This process continues until all the hydrogen at the core is changed to helium. Now, there is no more nuclear reaction in the center. The gravitational pull of the star makes the center get smaller, but hydrogen is available outside the center. Therefore hydrogen reactions happen in the outer layer, releasing more heat and light. The star expands, spreading heat to a larger area. In the process, the surface temperature is reduced, and the star transforms into a red giant. At this stage, the star can swallow up the celestial bodies that orbit around it.The mass of the star decides the later stages of a star. Average stars die relatively peacefully. The stars, up to about 1.4 times as massive as the mass of the Sun, form white dwarfs at their end stages. The star ejects the outer layers till the stellar core is exposed. The dead, yet hot stellar core, is called a white dwarf. White dwarfs are smaller yet denser. Massive stars result in denser white dwarfs. Though dense, white dwarfs do not collapse further. Astronomers observe that the fast-moving electrons exert pressure, which prevents the collapse of the stellar core or the white dwarfs. The white dwarfs, once cooled, form black dwarfs.On the other hand, massive stars die with an explosion. The pressure of their electrons cannot stop the stellar core from collapsing. These stars become red supergiant stars, exploding enormously. This tremendous scattering of gas and dust is referred to as the supernova. After the explosion, the stars are left with a smaller, yet denser ball. Astronomers refer to this as the neutron star. At this stage, the star has powerful magnetic fields that accelerate atoms’ particles, thus producing radiation.Much larger red giants, with a core above three solar masses, face a different fate. In such stars, the core collapses entirely and forms a black hole. The gravitational pull is very powerful that even light can not escape the black hole. A black hole cannot be detected directly by instruments.On the other hand, the debris left behind by the dying stars merges with interstellar gas and dust that make up the base for the birth of new stars.Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for how are stars born? Then why not take a look at how many legs do butterflies have? Or how are mirrors made?
Is there anyone who does not admire the sparkle of stars on a clear night sky?
