You might have. That line was from near the start of the 1961 movie, ‘Voyage To The Bottom Of the Sea’, (starring Frankie Avalon, Barbara Eden, Peter Lorre and Walter Pidgeon). The brand new nuclear powered ‘research’, (heh-heh, loaded with nuke missiles, some ‘research’ sub), submarine Seaview has just surfaced after 3 days below the Arctic Ice, out of all contact with the outside world, to discover that the sky is ‘on fire’. When radio contact is made to Wa. DC, Admiral Nelson asks “What’s that fire in the sky”. He is then told it that the Van Allen belt had exploded.
The only things I remember about that movie was that it was bad, and Barbara Eden. Just Wow.