Swamp gas?

I remember the story Momma told about something that happened when they lived in the country.It was the old home place at Bethel.That was where she was born and I am sure the others where also.Anyway one night they all where sitting on the front porch.Uncle Arnold was playing or trying to play his old guitar.From across the road where it was swamp land they seen a bright light.It was coming towards them and was orange.It was getting larger.It came up on the porch with them.Arnold swung his guitar at the light and it disappeared.What ever the light was they never knew.Momma just called it swamp gas.I often wondered if it was an orb.