This is Radio Luxembourg!
4 seconds sound clip from the The Day the Earth Stood Still (1954) classic radio play.
You can hear this line at 00:04:06 in the radio play.
Quote context
[...]
- But that's impossible! That thing must be doing about four thousand.
- That can't be aircraft, sir. Must be a buzz bomb.
- Better give an alarm. Keep it steady, though. May be faulty equipment.
- There was something very gravely wrong forty miles out in space, far above the earth.
- Luckton at Ferris to Baker, Ferris to Baker.
- I have an object at two zero zero thousand feet, four zero zero zero miles an hour.
[...]