As winter nights deepen and the year draws to a close, the Ursid meteor shower returns to the skies, offering a quiet yet compelling finale to 2025’s celestial
calendar. Often overshadowed by brighter meteor displays, the Ursids invite observers to slow down and look up, as fleeting streaks of light cut across the darkness. But what exactly are these flashes in the sky, and where do they come from? In this explainer, we unpack the science behind meteor showers -- how they form, why they are named the way they are, and what gives them their distinct colours. Far from being shooting stars, meteors are tiny fragments of cosmic debris that ignite as they enter Earth’s atmosphere, a process NASA says reveals important clues about our planet’s constant interaction with space. Here is the list of ten facts that were highlighted by NASA:
1. How meteor showers are formed
According to NASA, meteor showers take place when Earth passes through trails of debris left behind by comets or, in some cases, asteroids. These debris trails are spread along the orbit of the parent object.
2. What meteors are made of
Meteors are typically small pieces of rock and ice that break off from comets as they travel around the Sun. Over time, these particles form dense streams in space.
3. When a meteor becomes a meteorite
Most meteors burn up completely in the atmosphere. However, if a fragment survives the journey and reaches the Earth’s surface, it is known as a meteorite.
4. Why meteor showers have specific names
Meteor showers are named after the constellation from which they appear to originate, known as the radiant. For example, the Perseid meteor shower appears to come from the constellation Perseus.
5. Role of comets in sustaining meteor showers
NASA notes that comets continuously shed material each time they orbit the Sun. This ongoing process replenishes the debris streams that cause recurring meteor showers.
6. Frequency of meteor showers
There are around 30 meteor showers each year that are visible from Earth. Some of these have been observed for centuries. The Perseid meteor shower, for instance, has been recorded for nearly 2,000 years, including mentions in ancient Chinese records.
7. Why meteors show different colours
Meteors can leave behind red, yellow or green trails. These colours are produced when atmospheric gases such as oxygen become ionised due to the intense heat generated as the meteor enters the atmosphere.
8. What is a fireball
A fireball is an exceptionally bright meteor that outshines the planet Venus. These rare events are often visible over large areas and attract widespread attention.
9. Number of meteors entering Earth’s atmosphere
Radar observations suggest that on any given night, around 12,000 meteors, many no larger than grains of dust, enter Earth’s atmosphere, though most go unnoticed.
10. Protection against meteors in space
NASA says the International Space Station is equipped with shielding designed to protect it from meteors as large as one inch in diameter, ensuring the safety of astronauts onboard.
