Meteor shower

A meteor shower is a beautiful event in the night sky where many bright streaks of light, called meteors, seem to come from one place. These streaks happen when tiny pieces of space dust, called meteoroids, enter Earth's atmosphere very quickly. Most of these pieces are smaller than a grain of sand, so they burn up before they can reach the ground.

Sometimes, there are so many meteors that it looks like a storm of lights. These special events are called meteor outbursts or meteor storms. One famous example is the Leonids meteor shower.

Scientists have known for a long time that these meteors come from space. In 1866, an astronomer named Giovanni Schiaparelli discovered that the Leonid meteor shower comes from a comet. Comets leave behind trails of dust and ice, and when Earth passes through these trails, we see a meteor shower. Today, we know about many regular meteor showers and watch for them every year.

Historical developments

People have seen meteor showers for thousands of years. Old records from China, Japan, Korea, and places like Timbuktu talk about bright streaks of light in the sky. One of the oldest meteor showers, the Lyrids, has been written about since 687 BCE.

Scientists have studied these showers for a long time. In 1833, a big meteor storm happened over North America, with many shooting stars. This helped experts learn that meteors come from space dust. Later, they found that meteor showers are linked to comets — big icy objects that leave dust behind them. When Earth passes through this dust, we see meteor showers. Today, scientists can guess when these shows will happen by watching the paths of comets and Earth.

Radiant point

Main article: Radiant (meteor shower)

When you watch a meteor shower, all the streaks of light seem to come from one spot in the sky. This spot is called the radiant point. It works like when parallel lines, like railroad tracks, seem to meet far away on the horizon. Meteor showers are named after the star pattern where this point appears.

As Earth spins, the radiant point moves slowly across the sky during the night. The best time to see a meteor shower is usually just before dawn, when the radiant point is high in the sky. This gives you the best chance to see these bright streaks of light.

Naming

Meteor showers are named after the brightest star or area in the sky where the meteors appear to come from. This area is often part of a group of stars called a constellation. For example, if meteors seem to come from a spot near a star called Delta Aquarii, the shower is called the Delta Aquariids. Scientists, like the International Astronomical Union's group for naming meteor showers, help decide the official names.

Origin of meteoroid streams

A meteor shower happens when Earth moves through bits of debris left by a comet or sometimes an asteroid. These bits, called meteoroids, can come off a comet in different ways. When a comet gets close to the Sun, its ice warms up and turns into gas. This gas can pull along tiny pieces of dust, sand, and small rocks.

Every time a comet passes the Sun, it leaves some of these bits behind. Over time, they spread out along the comet's path, forming a stream of meteoroids. When Earth crosses this stream, we see a meteor shower. Some meteor showers come from old breakups of objects that look like asteroids, such as the Quadrantids and Geminids. These pieces also spread out and create the beautiful streaks of light we see in the sky.

Dynamical evolution of meteoroid streams

Milos Plavec first suggested that dust particles from comets form trails when they break away. We can sometimes see these trails in pictures of comets.

The paths of these trails are shaped by the gravity of planets. Most years, Earth misses these trails, but sometimes we pass through them and see a meteor shower. Over many years, these trails change because of the pull of planets like Jupiter and the push of sunlight. This can create gaps or clusters in the trails. These changes mean that some meteor showers have more bright meteors, while others have fainter ones. Over time, these trails spread out, leading to the annual meteor showers we see each year.

When meteoroids collide with others in space, they become part of the background of random "sporadic meteors" that appear anywhere in the sky.

Meteor storm

A meteor storm is a special and bright version of a meteor shower. During a meteor storm, you can see at least 1,000 meteors every hour—much more than a regular meteor shower. Famous examples include the Leonids and the Draconids. These storms can look like stars falling from the sky or like fireworks.

The Leonids are well-known for creating these amazing shows. Leonid meteor storms happen about every 33 years when Comet Tempel–Tuttle returns. Big storms happened in 1833, 1966, 1999, and 2002. The next big Leonid storm might not happen until around 2034 or even 2099.

The Draconids also created big storms in 1933 and 1946, and scientists think they might do so again in 2098. There might also be a bright Perseids storm in August 2028.

Famous meteor showers

The peak rate of a meteor shower is measured by the zenith hourly rate. This tells us how many meteors we might see when the shower’s point in the sky is highest. Some meteor showers can have many meteors flying by in just one hour! The showers with the most meteors are usually the Perseids, Geminids, and Quadrantids.

In most years, the Perseids is the most reliable meteor shower, happening every year on August 12th. You might see more than one meteor every minute! The Leonid meteor shower happens around November 17th each year.

Further information: List of meteor showers

Extraterrestrial meteor showers

Just like Earth, other planets and moons in our Solar System can have meteor showers. The Moon can see the same meteor showers as Earth, but they look different because the Moon has no atmosphere. Scientists at NASA’s Marshall Space Flight Center watch for impacts on the Moon.

Mars and its moons also have meteor showers. These look different from Earth’s because Mars has a thinner atmosphere. But up high, where meteors appear, the air pressure is similar to Earth’s, so they look almost the same. On March 7, 2004, a camera on the Mars Exploration Rover Spirit captured what may be a meteor from a Martian meteor shower. This meteor was linked to a comet named 114P/Wiseman-Skiff. Scientists have also thought about possible meteor showers on other worlds like Titan, Triton, and Pluto.