# Listen&Learn: The Speed of Light

Jaksyn Peacock
Learn how scientists use the speed of light to measure distances between stars.

## Pre-listening vocabulary

• theory: a scientific explanation for something
• vacuum: a completely empty space
• constant: never changing or stopping
• exoplanet: a planet outside of our solar system
• visible: able to be seen

## Gapfill exercise

Einsteinâ€™s theory of special relativity states that it is for anything to travel faster than light. In a vacuum, light travels at a constant speed of 299,792,458 metres per second. Scientists use the speed of light to distances between stars in space. A light-year is a that represents the distance that light can travel in a year. Even the closest stars and exoplanets are removed from our system by several light-years. Proxima Centauri, the closest star to the Sun, is about 4.25 light-years away. Some visible stars are thousands of light-years away. This means that the night sky is an image of the . In fact, it is possible that some of the stars we can see no longer exist.

## Comprehension questions

1. Einstein’s theory of special relativity states that
a. it is impossible for something to travel faster than light
b. light travels at an accelerating speed
c. the light from stars reaches Earth almost instantly
2. A light-year is a measure of
a. time
b. distance
c. energy
3. The closest star to the Sun is about
a. 4.25 light-years away
b. 299 light-years away
c. 1000 light-years away

## Discussion/essay questions

1. Einstein’s theory of special relativity also states that speed can change the way we experience time. Do you think time travel will ever be possible? Why or why not?

## Transcript

Einsteinâ€™s theory of special relativity states that it is impossible for anything to travel faster than light. In a vacuum, light travels at a constant speed of 299,792,458 metres per second. Scientists use the speed of light to measure distances between stars in space. A light-year is a unit that represents the distance that light can travel in a year. Even the closest stars and exoplanets are removed from our solar system by several light-years. Proxima Centauri, the closest star to the Sun, is about 4.25 light-years away. Some visible stars are thousands of light-years away. This means that the night sky is an image of the past. In fact, it is possible that some of the stars we can see no longer exist.

1a 2b 3a

Written and recorded by Jaksyn Peacock for EnglishClub

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• Abnar says:

Thanks so much , it was very enjoyable

• GLON jOSEPHI says:

we are surrounded by something that can we see but does not exixt yet
could you imagine our state of beeing
have a good day

• The King Of Love From IRAN says:

Thank you for sharing it with us,