Listen&Learn: Brown dwarfs

Learn about the objects that scientists sometimes call “failed stars”.

Pre-listening vocabulary

• dwarf: a type of star that is small and faint
• celestial: relating to space
• classify: to sort something into a category
• compress: to make something smaller and more dense
• core: the centre of a planet or star
• fuse: to combine things together
• deuterium: a variation of hydrogen

Listening activity

Podcast: Play in new window | Download (Duration: 1:25 — 1.3MB)

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Gapfill exercise

A brown dwarf is a type of celestial object that can’t be classified as a or a star. Although brown dwarfs look more like planets, they form the same way stars do. A star is created when a of gas and dust begins to compress. The intense force of 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 and fuse deuterium until they run out. Brown dwarfs produce very little , which makes them hard to find. Scientists first theorized about brown dwarfs in 1963, but didn’t observe any until 1995. 

Comprehension questions

1. Brown dwarfs look like
   a. planets
   b. stars
   c. asteroids
   
2. 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
   
3. 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

See answers below

Discussion/essay questions

1. 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. 

Answers to comprehension questions

1a 2a 3c