Philip Hale had just passed the gates to the old Laughton Lodge Hospital at Laughton at 9.55am when the object flew in down in fields to his right.
'It was a white object with a blue tail flame travelling very fast on a trajectory of about 45 degrees down to the Earth,' he said.
'The object must have crashed in a field.
'Did anybody else see it? Was it a meteorite or a fireball or what else could it have been?'
Mr Hale said the object was about 800 yards away and in his sight for several seconds.
'I didn't stop. Perhaps I should have,' he added. 'I'd never seen anything like it before in my life. There should be some evidence in the field of its impact.'
A spokesman for Sussex Police said nothing had been reported to them.