A quasar is a. a massive and luminous galaxy b. a star that emits an unusual amount of radio waves c. a bright galactic nucleus powered by a black hole
Scientists first discovered quasars in a. 1913 b. 1931 c. 1961
Most quasars are a. billions of light years away b. close to the Milky Way Galaxy c. almost as old as the universe
Discussion/essay questions
What do you think the purpose of studying space is? Why do humans want to understand the universe?
Transcript
A quasar is a celestial object that emits enough radiation to glow brighter than a galaxy. The energy that a quasar emits comes from a supermassive black hole at its centre. When scientists first observed quasars in 1961, they thought they were stars, or star-like objects. The name “quasar” is an abbreviation for “quasi-stellar radio source”, because the first observed quasars looked like stars that emitted lots of radio waves. Scientists now know that quasars are the nuclei of young galaxies. Even though quasars are very bright, most of them are billions of light years away, which means that observing them can provide information about the state of the universe in the distant past. The oldest discovered quasar formed nearly 13 billion years ago, at the very beginning of the universe’s life.
All stars die , but different stars can die in very different ways. Our Sun is a medium-sized star. That means that when the Sun dies, it will simply turn into something called a white dwarf. White dwarves are small, dense celestial objects that contain the matter left over from stars. However, some stars are much more massive than our Sun, and their deaths are much more . When a massive star gets older, it starts to cool down. This is because the star is using up the last of its . Once the star has no fuel left, it will implode. This implosion is called a supernova. The event is so bright that if a star in our galaxy caused a supernova, we could possibly see it from Earth. The force of a supernova causes the star’s mass to be compressed into a very small space with an incredibly strong gravitational pull. This is called a black hole, and it is so that nothing can escape from it.
Comprehension questions
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Discussion/essay questions
Scientists believe that over 1,000 years ago, ancient civilizations witnessed a bright supernova. Now, scientists are observing a dying star called Betelgeuse, which may go supernova soon. Do you think it’s possible that we could see a supernova in our lifetime?
Transcript
All stars die eventually, but different stars can die in very different ways. Our Sun is a medium-sized star. That means that when the Sun dies, it will simply turn into something called a white dwarf. White dwarves are small, dense celestial objects that contain the matter left over from dead stars. However, some stars are much more massive than our Sun, and their deaths are much more violent. When a massive star gets older, it starts to cool down. This is because the star is using up the last of its fuel. Once the star has no fuel left, it will implode. This implosion is called a supernova. The event is so bright that if a star in our galaxy caused a supernova, we could possibly see it from Earth. The force of a supernova causes the star’s mass to be compressed into a very small space with an incredibly strong gravitational pull. This is called a black hole, and it is so powerful that nothing can escape from it.
