A very bright light green ball shaped light travelling soundlessly and rapidly in a horizontal direction at 800 to 1000' at 4:33am.My husband was up briefly at 4:30am April 21st. We have uncovered sliding doors onto a balcony in our bedroom. We live in the country and the bedroom is on the second floor. He went back to bed, lying facing the balcony door. Almost immediately he sat up and said 'what's that' and got out of bed. I followed him and we went out onto the balcony. A luminous light green ball shaped light raced horizontally across our view from south to north. There was no sound involved and it moved very quickly. There was no rising, falling or hesitation. It was at about 800 to 1000 feet off the ground. From our viewpoint it appeared to be 1/4 to 1/5 the size of the full moon. My husband is a ((deleted--professional)) and has had his private pilots licence in the past. I am a ((deleted--professional)). It was not an airplane.((NUFORC Note: Case has been shared with a group of Canadian astronomers, with whom we work closely. They will investigate whether their sky-cameras may have recorded the event. PD))