His explanation was impossible to understand.

He is world-famous as an astronomer.

He has astronomical knowledge.

Please use the emergency stairs in case of a fire.

Due to the earthquake, the city declared a state of emergency.

There is a new radio clock in my room.

He is interested in radio wave research.

What is your favorite denpa song?

The problem of space debris could potentially have a significant impact on future space development.

The study of cosmic rays may hold the key to unraveling the mysteries of the universe.