What Causes Lightning?

When you think of a thunderstorm, you likely immediately think about lightning, too. Lightning is an incredible phenomenon that can scare and amaze us. For many, the question of what causes lightning is something that may surprise them. While the answer is actually quite simple, the exact scientific explanation behind it is actually extremely complex.

The Basics of Lightning

The basic explanation of what causes lightning is quite simple. Lightning is caused by a buildup of static electricity in a cloud. When air currents inside the cloud move around and eventually collide, this static electricity is discharged as a bolt of lightning.

The Comprehensive Explanation

When exploring the comprehensive explanation behind what causes lightning, one must understand the fundamentals of thunderstorms. Thunderstorms are a collision between warm, humid air and cool, dry air that causes an area of low pressure. It is this area of low pressure that forces the formations of clouds and causes them to carry a charge of static electricity.

When a cloud forms, the particles known as aerosols inside the cloud experience a shift in their molecules. The negative molecules move to the bottom of the cloud while the positive molecules move to the top. The separation of these charged particles creates static electricity, which can reach a point of imbalance between the two charges.

When the static electricity within the cloud too great to contain, electrical pathways known as streamers form from the cloud to the ground. The streamers catalyze a discharge of the static electricity, traveling through the atmosphere at about one-third the speed of light in a matter of milliseconds. The lightning strike is accompanied by a sound we recognize as thunder.

The Formation of Lightning

So what causes lightning? The answer is a three-part formation between the positive and negative particles inside the cloud, the buildup of static electricity, and the formation of the electrical pathways known as streamers. In just a matter of minutes, the static electricity builds enough of a charge within a cloud to create the phenomenon that amazes us.