Brown dwarfs look like a. planets b. stars c. asteroids
Brown dwarfs are different from stars because a. they use deuterium for fusion b. they don’t have cores c. they reach extremely high temperatures
It is difficult to find brown dwarfs because a. they don’t orbit anything b. they are smaller than most planets c. they emit very little light
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Discussion/essay questions
Scientists are always learning more about space. What do you think will be discovered in the future?
Transcript
A brown dwarf is a type of celestial object that can’t be classified as a planet or a star. Although brown dwarfs look more like planets, they form the same way stars do. A star is created when a cloud of gas and dust begins to compress. The intense force of gravity causes the star’s core to fuse atoms together, producing helium. Fusion is what causes a star to shine. Early in its life, a star fuses atoms of deuterium. It begins to use regular hydrogen as its core gets hotter. However, brown dwarfs never reach this stage. They stay at low temperatures and fuse deuterium until they run out. Brown dwarfs produce very little light, which makes them hard to find. Scientists first theorized about brown dwarfs in 1963, but didn’t observe any until 1995.
Dark energy is a force that exists throughout the universe. It is believed to make up about 68% of everything that exists, and it affects the way the universe is expanding. have known about the expansion of the universe since 1929. But for many years, most believed that the force of gravity would eventually slow down this expansion. However, in the 1990s, a team of astronomers that the universe was actually expanding than it had been years before. They came to the conclusion that there was another force, called dark energy, that was causing the expansion to accelerate. Dark energy is even than gravity, and scientists still don’t know much about it. It has often been called the universe’s greatest mystery.
Comprehension questions
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Discussion/essay questions
There is a lot to learn about the universe. If you could ask an astronomer any question, what would you ask?
Transcript
Dark energy is a mysterious force that exists throughout the universe. It is believed to make up about 68% of everything that exists, and it affects the way the universe is expanding. Scientists have known about the expansion of the universe since 1929. But for many years, most believed that the force of gravity would eventually slow down this expansion. However, in the 1990s, a team of astronomers observed that the universe was actually expanding faster than it had been years before. They came to the conclusion that there was another force, called dark energy, that was causing the expansion to accelerate. Dark energy is even stronger than gravity, and scientists still don’t know much about it. It has often been called the universe’s greatest mystery.
What are your beliefs about the universe? Do you think there is life on other planets?
Transcript
Cosmos is a popular science book written by astronomer Carl Sagan. The book was published in 1980, when Sagan was hosting a documentary series with the same name. The goal of both the book and the series was to introduce the general public to astronomy. The book has 13 chapters, which match up with the 13 episodes of the documentary series. At the time, Sagan’s work caused many people to become interested in understanding space and science. In 2014 —18 years after Sagan’s death— a remake of the original Cosmos series aired on TV. Though scientists’ understanding of the universe has grown since 1980, Cosmos is still one of the most famous scientific books ever published.
