What causes a shooting star in the night sky?

The night sky has always captivated humanity's imagination, and one of the most enchanting phenomena it offers is the shooting star. But have you ever wondered, what causes a shooting star in the night sky? 

In this article, we'll delve into the science, wonder, and beauty of these celestial events. Join us on this journey through the cosmos.

The basics of shooting stars

Shooting stars, scientifically known as meteors, are streaks of light that appear in the night sky when small particles from space, known as meteoroids, enter Earth's atmosphere. As these meteoroids hurtle through the atmosphere, they heat up due to friction, creating the spectacular glow that we see from the ground.

The atmospheric entry

The mesmerising display of a shooting star begins when a meteoroid enters the Earth's atmosphere. As it descends through the atmosphere at incredible speeds, friction with air molecules causes the meteoroid to heat up rapidly. This intense heat causes the meteoroid to glow, creating the bright streak of light we observe from the ground. This luminous phenomenon is what we commonly refer to as a shooting star.

The role of meteoroids

Meteoroids, which can range in size from tiny grains of sand to small boulders, originate from various sources in our solar system. Some come from asteroids, while others are remnants of comets. When these meteoroids collide with Earth's atmosphere, they become meteors.

Meteor showers

While individual shooting stars are a captivating sight, they are often part of a larger celestial event known as a meteor shower. Meteor showers occur when the Earth passes through the debris left behind by a comet's orbit. The tiny particles from the comet, mostly no larger than grains of sand, enter the Earth's atmosphere and create a flurry of shooting stars. The Perseids and the Geminids are two well-known meteor showers that stargazers eagerly anticipate each year.

What causes the flash?

The flash of light that we observe when a meteoroid enters our atmosphere is due to its extreme velocity. As it travels through the air, it compresses the air in front of it, creating a high-pressure region. This compression causes the air to heat up and emit light, forming the bright streak we associate with shooting stars.

The importance of speed

The speed at which meteoroids enter the atmosphere is a crucial factor in determining the intensity of the meteor shower and the brightness of the meteors. Faster meteoroids tend to produce more brilliant and longer-lasting streaks, making for a more dazzling display.

Why do they disappear?

As meteoroids travel through the atmosphere, they lose mass due to ablation. Ablation is the process of material gradually vaporising from the surface of the meteoroid as it burns up. Eventually, the meteoroid becomes so small that it can no longer produce enough light to be visible from the ground, and it fades away, leaving behind the memory of its fleeting journey.

Shooting Star Varieties

Shooting stars come in various forms, depending on their composition and size. Here are some common types:

• Perseids

The Perseids are one of the most famous meteor showers, occurring annually in August. They are associated with the debris left behind by Comet Swift-Tuttle. Observers can typically witness dozens of bright shooting stars per hour during the peak of this meteor shower.

• Geminids

The Geminids are unique among meteor showers as they originate from an asteroid, 3200 Phaethon, rather than a comet. They occur in December and are known for producing numerous bright and colourful shooting stars.

• Taurids

The Taurids are a long-lasting meteor shower that occurs in late October and early November. They are associated with Comet Encke and are known for producing a higher number of fireball meteors, which are exceptionally bright shooting stars.

• Leonids

The Leonids are famous for their periodic meteor storms, during which thousands of meteors can be seen in an hour. These storms occur roughly every 33 years and are linked to Comet Tempel-Tuttle.

The mythology and magic

Throughout history, shooting stars have been the subject of myths, legends, and wishes. Many cultures have associated them with supernatural events or considered them omens. The idea of making a wish upon a shooting star is a tradition that persists to this day, adding a touch of magic to our nightly skywatching.

If you're interested in knowing more about shooting stars, you can read this article next: 'What makes a shooting star glow?.