If you make a habit of looking up at the night's sky, sooner or later, you'll see a meteor. It's possible to see meteors, otherwise called shooting stars, on any night of the year, providing the sky is dark enough. However, some nights and times of year are much better for seeing shooting stars than others. Let's take a look at what meteors are and how you can witness a meteor shower.
Meteoroids are relatively small pieces of celestial debris (space rocks) that enter the Earth's atmosphere.
Meteoroids are relatively small pieces of celestial debris (space rocks) that enter the Earth's atmosphere. But where do they come from? Meteoroids start their life as much larger comets. Comets are the frozen leftovers from the solar system's formation, and they can come in many shapes and sizes. They can range from a few miles in width to several tens of miles. Typically, comets are composed of ice, rock, and loosely held together dust.
While the Earth's orbit around the Sun is almost circular, this is not the case for comets. Most comets travel around the Sun in a highly elongated elliptical orbit that partially overlaps Earth's orbit. When the comet passes in front of the Sun, some of its icy surfaces starts to boil, loosening the rocks and dust and producing a visible tail. This loosened debris then gets strewn out along the comet's path and into the inner solar system. When the Earth intersects the comet's orbit as it makes the annual trip around the Sun, it collides with the celestial debris, capturing it.
A meteor is the streak of light you see in the sky when a meteoroid comes crashing into the atmosphere. On their own, meteoroids are simply small lumps of rock, iron, or dust, but they become shooting stars when they collide with Earth's air molecules at high speed. This occurs because of the high level of kinetic energy released in the collision and the rapid ionisation of the atoms surrounding the meteoroid.
Sometimes several meteors will rain down on Earth, and this is what we call a meteor shower. This happens because the Earth has passed through a region of space with a high concentration of celestial debris.
The most intense form of a meteor shower is called a meteor storm, which produces at least 1000 meteors an hour. The most famous meteor storm, called the great Leonid meteor storm, happened in 1833 and spawned more study into the topic than any other event.1
Most meteors are easily visible without a telescope but are not exceptionally bright. However, occasionally we do get meteors that light up the sky. These meteors can even be brighter than Venus or the moon.
You can reliably observe meteor showers at certain times of the year, depending on when Earth is scheduled to pass through a known area of celestial debris. We name meteor showers based on where it looks like they are coming from in the sky. For example, the Perseid meteor shower that you can see every year in July and August gets its name because it appears to originate from the Perseus constellation.
Below are the most prominent meteor showers and when they occur2. Please note that the dates here are for 2021, but these meteor showers occur around the same time every year.
- Quadrantids: 28 Dec-12 Jan with approximately 120 meteors per hour.
- Lyrids: 13-29 April with around 18 meteors per hour.
- Eta Aquariids: 18 April-27 May with over 40 meteors per hour.
- Delta Aquariids: 13 July - 24 Aug with less than 25 meteors per hour.
- Perseids: 16 July-23 Aug with over 150 meteors per hour.
- Geminids: 3-16 December with over 120 meteors per hour.
Go find some shooting stars!