STARS
I learned the following information from an article at the website of Thinkquest.
Stars are often born in interstellar nebulae, which are huge clouds of matter in the form of gas and dust. The particles in these clouds compress under the gravity of the clouds and due to increased atomic collisions they heat up greatly. The star is born when it heats up enough to fuse hydrogen atoms into helium. The majority of a star’s life is spent fusing hydrogen into helium and other elements. Its core uses up the elements within over billions of years.
The larger the mass of a star is, the shorter its life is. When a star ceases to fuse elements into other elements, the fate of the star depends on its size.
A star the size of the Sun will ultimately expand up to one hundred times its size and become what is known as a “red giant.” As the helium in its core runs out it shrinks. The gravitational force within the star becomes so great that it crushes the star into a star called a “white dwarf,” which is many times smaller than the star originally was. The white dwarf will shine for many more years until it burns out and is merely a remnant of matter densely compacted.
A star smaller than the Sun burns until the fuel in its core is depleted. Then the gravitational force of the star’s center overpowers the star and it is crushed. It becomes a “brown dwarf,” with no energy left to emit light.
A star more than ten times the size of the sun begins to expand rapidly after it exhausts its fuel. It continues to expand until it is huge and on fire, known as a “supergiant.” The supergiant expands violently and loses energy for it radiates most of its energy away. This is in the form of an explosion that is known as a “supernova.” The remnant of a supernova often forms nebulae.
Four supernovae have been observed in the last millennium: The Chinese witnessed one in 1054 AD, Tycho Brae witnessed one in 1572, Kepler witnessed one in 1604, and the most recent one occurred in 1987.
The remains of the star are finally crushed by gravity and supercompressed into an extremely dense object known as a “neutron star.” A neutron star’s mass is compressed so densely that the protons and electrons are crushed together into neutrons.
A pulsar is a neutron star that spins and emits radio waves.
A star more than thirty times the size of the sun begins to expand once it exhausts its fuel. It expands into a supergiant and then into a supernova. Unlike a smaller star, though, the huge mass of this star causes such a huge gravitational force from its center that it becomes infinitely compressed. It becomes a “black hole,” from whose gravitational pull nothing can escape. A black hole is also called a singularity. Scientists believe that the universe was created by a black hole. According to a theory, the universe could compress itself back into a singularity or black hole, and explode, which would begin the process again, and this pattern would repeat for all eternity.
I learned the following information from an article at the website of Thinkquest.
Stars are often born in interstellar nebulae, which are huge clouds of matter in the form of gas and dust. The particles in these clouds compress under the gravity of the clouds and due to increased atomic collisions they heat up greatly. The star is born when it heats up enough to fuse hydrogen atoms into helium. The majority of a star’s life is spent fusing hydrogen into helium and other elements. Its core uses up the elements within over billions of years.
The larger the mass of a star is, the shorter its life is. When a star ceases to fuse elements into other elements, the fate of the star depends on its size.
A star the size of the Sun will ultimately expand up to one hundred times its size and become what is known as a “red giant.” As the helium in its core runs out it shrinks. The gravitational force within the star becomes so great that it crushes the star into a star called a “white dwarf,” which is many times smaller than the star originally was. The white dwarf will shine for many more years until it burns out and is merely a remnant of matter densely compacted.
A star smaller than the Sun burns until the fuel in its core is depleted. Then the gravitational force of the star’s center overpowers the star and it is crushed. It becomes a “brown dwarf,” with no energy left to emit light.
A star more than ten times the size of the sun begins to expand rapidly after it exhausts its fuel. It continues to expand until it is huge and on fire, known as a “supergiant.” The supergiant expands violently and loses energy for it radiates most of its energy away. This is in the form of an explosion that is known as a “supernova.” The remnant of a supernova often forms nebulae.
Four supernovae have been observed in the last millennium: The Chinese witnessed one in 1054 AD, Tycho Brae witnessed one in 1572, Kepler witnessed one in 1604, and the most recent one occurred in 1987.
The remains of the star are finally crushed by gravity and supercompressed into an extremely dense object known as a “neutron star.” A neutron star’s mass is compressed so densely that the protons and electrons are crushed together into neutrons.
A pulsar is a neutron star that spins and emits radio waves.
A star more than thirty times the size of the sun begins to expand once it exhausts its fuel. It expands into a supergiant and then into a supernova. Unlike a smaller star, though, the huge mass of this star causes such a huge gravitational force from its center that it becomes infinitely compressed. It becomes a “black hole,” from whose gravitational pull nothing can escape. A black hole is also called a singularity. Scientists believe that the universe was created by a black hole. According to a theory, the universe could compress itself back into a singularity or black hole, and explode, which would begin the process again, and this pattern would repeat for all eternity.
posted by Caroline at 9:16 PM
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