Eco

The transcript explains the concept of echoes, typically associated with sound, but applicable to any wave energy form. It highlights how astronomers observe light echoes when light from energetic events reflects off dust or gas clouds.

What is an echo in the context of sound?

• A sound that is absorbed by a surface

• A sound that is heard again after being reflected

• A sound that is heard before the original sound

• A sound that is produced by a musical instrument

Which of the following can produce an echo?

• Only light waves

• Only sound waves

• Only water waves

• Any type of energy in wave form

What is a light echo?

• Light that is absorbed by a black hole

• Light that is emitted by a star

• Light that travels in a straight line

• Light that is reflected off clouds of dust or gas

In what context do astronomers use the term 'light echoes'?

• When light is refracted through a prism

• When light is emitted by galaxies

• When light is reflected off dust or gas clouds

• When light is absorbed by planets

Which phenomenon involves light being reflected off clouds of dust or gas?

• Sound echo

• Light echo

• Heat echo

• Water echo