Where does lightening originate? Ground to sky or sky to ground?

Answer 1

As a thundercloud moves over the Earth's surface, an equal but opposite charge is induced in the Earth below, and the induced ground charge follows the movement of the cloud.

When the electric field becomes strong enough, an electrical discharge (the bolt of lightning) occurs within clouds or between clouds and the ground.

Cloud-to-cloud
Intracloud lightning is the most common type of lightning, and occurs completely inside one cumulonimbus cloud; it is termed sheet lightning because the bolt is not seen, instead one sees the whole cloud light up from inside. Lightning that appears to travel extensively along the cloud anvil or its base is commonly called a crawler, or sometimes 'spider lightning'. Discharges of electricity in anvil crawlers travel up the sides of the cumulonimbus cloud branching out at the anvil top.


Rocket lightning
It is a form of cloud discharge, generally horizontal and at cloud base, with a luminous channel appearing to advance through the air with visually resolvable speed, often intermittently. The movement resembles the movement of a rocket, hence its name. It is also one of the rarest of cloud discharges.


Cloud-to-ground

Cloud to ground lightning strikeCloud-to-ground lightning is a great lightning discharge between a cumulonimbus cloud and the ground initiated by the downward-moving leader stroke. This is the second most common type of lightning, and poses the greatest threat to life and property of all known types.

http://en.wikipedia.org/wiki/Lightning

Answer 2

Both. Lightning follows a stepped leader and this can come up from the ground or from sky to the ground.

Answer 3

http://www.srh.noaa.gov/srh/jetstream/lightning/lightning_faq.htm

Does lightning travel from the cloud to the ground, or from the ground to the cloud?
An entire lightning strike employs both upward and downward moving forces. However, the return stroke of a lightning bolt travels FROM THE GROUND INTO THE CLOUD and accounts for more that 99% of the luminosity of a lightning strike. What we SEE as lightning does indeed travel from the ground into the cloud.

Answer 4

Ground to sky

Answer 5

sky to ground and sky to space equal and opposite reactions positive and negative charged clouds rubbing together. first it sends a carrier wave like a laser sight to a target then the main charge follows