Green ball of light , it moved at incredable speed.

I don't have the exact date of my one and only sighting of which i am convinced of still, all these years later was a UFO. I just canot explain it and nothing has come about in the last twenty years that can. There are no planes, Shuttle Craft, Or anything else that has been invented that i know of that looks any thing like what i saw. Myself and a friend were on a fishing trip in west cork,We were about ten miles from the coast heading down a rural road driveing at mabey fifty miles an hour.I am going down a slight hill and on both sides there are hedgerows with small spindely trees every so often and its hilly country side were driveing trough, Its dark and about one o'clock in the morning, All of a sudden with no warning a green light passed across the car from left to right like a scan the light did not seem to enter the car, It made a noticeable movement that i can only describe as being like a fine line of light that did not spread out and light up the whole road only the area we were in. It had a difference about it that i have never come across again.As it crossed away from the right hand side of the car i caught a breef glims of something glowing green moveing away over a slight hill the glims only lasted a few seconds. By the time i stoped the car and got out it had vanished, Myself and my friend just stood there with no explaination as to what had just happened I asked if he'ed seen it, He said he had,We were amased but only stayed a few minutes at the place and drove on, its odd but i dont realy remember us haveing much to say about it as we drove to the coast were we saw it again, It must have been fifteen or twenty minutes later when we got to the beach i had stoped and parked the car and was eager to get out of it and look at the sky it was a very clear night with very little cloud and as i looked out over the sea i saw it, it must have been a few miles out and hovering over the sea, It was a green ball of light, pure green light,It held there for a couple of seconds two at the most and then in a flash it raced acrossed the sea and it was gone.My friend said he only saw a flash of green light at the horizon as he got out of the car. I swear that this sighting is true, It has left me hopeing that in my lifetime it will be proved that were not alone in this universe that there is life on other planets, Hopefully not too much longer, I cant see how it can be hidden any more. P.S. IT MADE NO SOUND.
Witness indicates that the date of the event is approximate.  PD