Does Lightning Travel up or Down?

Michael Anissimov
Michael Anissimov

This is somewhat of a trick question — technically lightning does both. Let's take a look at the process through which lightning is known to be formed. This phenomenon occurs because of a difference in charge between a storm cloud and the ground.

Positive lightening travels in reverse by going from the ground up into clouds.
Positive lightening travels in reverse by going from the ground up into clouds.

First, the base of a cloud sends down a little electric discharge, called a stepped leader. It descends to the ground in steps, each about 50 yards (about 46 meters) in length. This process is extremely fast and impossible to see with the naked eye. Each step is less than a millionth of a second long. The interval between steps works out to about fifty-millionths of a second. This process can only be observed with the assistance of extremely quick-exposure cameras.

Lightning can travel both up and down.
Lightning can travel both up and down.

The stepped leader generally moves at about 75 miles per second (120 km/s) towards the ground. A typical trip duration is 20 milliseconds. Atoms pass along electrical charge much more quickly than sound vibrations.

The stepped leader carries tons of negative charge. As it nears the ground, it induces enormous quantities of positive charge in the earth, especially at the tips of tall objects. Because opposites attract, the stepped leader and the negative charge at the ground reach towards each other and quickly meet. The path from storm cloud to the surface is complete and the charge can move.

Because the cloud is filled with negative charge, it has a lot of current to offer to the newly created discharge path. This charge quickly moves from being distributed throughout the cloud to being concentrated at the point where the stepped leader first dropped from the cloud, into the ground or an elevated object. This discharge is called the return stroke, and is what we think of when we hear the word "lightning".

The return stroke takes around 100 millionths of a second to reach the ground. The immense flash generated is enough to leave an afterimage in our eyes for seconds at a time, giving us the illusion that the lightning flash is longer than it really is. In reality, our eyes cannot resolve any of the steps involved. We only see the final product — a lightning bolt.

Storm clouds carry an electrical charge.
Storm clouds carry an electrical charge.
Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments


@Leonidas226 – How horrifying! I suppose the charge from your heads was going up to meet the charge in the sky at that time.

I'm amazed that jumping in the van saved you. Did lightning strike the van at all, or did it strike the ground next to it?

I have been at the beach before during a thunderstorm, but the clouds were out over the water, so I thought I was safe. In Florida, there is a thunderstorm over the ocean about every day, and no one thinks much about it. Your story scares me a little.

It amazes me how thunder and lightning happen so fast, yet we can't hear or see them until several seconds after they happen. I've always heard that you can tell how many miles away lightning is by counting the seconds between the time you see it and the time you hear the thunder, but I did not know until reading this article that you only see the afterimage of lightning.

I have been in thunderstorms where the sound of thunder happened so quickly after the flash that I knew I had to be right in the middle of the storm. Luckily, I was inside the house.

When you are that close to a storm, you don't stand by the window and watch to see whether the lightning goes up or down. I actually hid in the closet with my terrified Doberman. I have heard stories of people getting struck inside their own homes, and I wanted to get in the spot that was totally windowless and doorless.


I have seen some good lightning photos, but they were only of the actual streaks of lightning in their full glory. I have never seen a photo of a partial streak that has only reached partway from the cloud to the ground, and I probably never will, since it happens so quickly.


Thunderstorms are like static electricity on a massive scale. I had a friend who was hit by lightning. Luckily, he survived, but he said it felt like someone whacked him in the head with a massive baseball bat. He was laid out flat.


Lightning protectors were invented by Ben Franklin. Before them, houses would light on fire when struck by lightning, and the fire department was kept busy during thunderstorms. Small towns would band together to keep fires down. This helped to foster community, but was also highly dangerous.


I was at a beach recently when my family and friends began to notice that our hair was sticking up in a thunderstorm which had suddenly arrived. Luckily, we were about to get into the van, so we quickly hopped in. This is usually the second stage before lightning hits. It is sometimes best to jump onto the ground when this kind of thing occurs, but often the process is so quick that there is little or no time to react.


Light is so immensely fast that it goes beyond time. We are still at a loss to understand how it works completely. It is both a wavelength and particles. The electronic function is almost light speed, but not quite. Sound is much slower, being more akin to feeling of the surrounding environment.

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