Most everyone has encountered that moment of surprise and wonder as a streak of light in the night sky catches your attention, providing a glimpse of a shooting star racing to Earth. For millennia, people have experienced that very moment, pondering timeless questions. Several of those questions will be the focus of this article.
What Is A Shooting Star?
Actually, a shooting star is not a star at all. The reference to a star has more to do with its appearance. It looks like a star, bright and sparkly, falling out of the sky, but its scientific term is a meteor. The terms shooting or falling star are both purely conversational and not scientific.
Our solar system is full of dust, space rocks, ice, and clouds of fine debris the size of a grain of sand. Mostly remnants from our galaxy the Milky Way’s ancient past. This debris, while in outer space is referred to by the term meteoroid.
According to the American Meteor Society, the size of a meteoroid ranges from a small nanoparticle (30 micrometers) up to 1 meter. Space dust smaller than 30 micrometers is referred to as a micrometeoroid. All rock, iron, or ice debris (not a comet) more significant than 1 meter classifies as an asteroid.
As the meteoroid enters the Earth’s upper atmosphere, it is then classified as a meteor, or what most people think of as a shooting star.
Shooting stars (meteors) become visible once they are in the mesosphere approximately 30-50 miles (50-100kn) up in the Earth’s atmosphere. Most will vaporize within seconds or less, but the faster, larger meteors which make it to the Earth’s surface are then referred to as meteorites.
What Causes A Shooting Star?
A Shooting star happens when a meteoroid enters the Earth’s atmosphere at an extremely high speed producing friction or drag against the atmospheric air molecules. This friction creates heat, burning off chemicals within the meteor and causing the atmospheric gasses surrounding it to illuminate. The result produces bright streaks of light as the meteor descends through the sky.
Types Of Shooting Stars
Earth Grazers
Earth Grazers are known for their long colorful tails enhanced by their trajectory path close to the horizon. They sometimes bounce off the atmosphere and return to space because of their angle of entry into the atmosphere.
Fireballs
These bright meteors range from the size of a basketball to a small vehicle. The International Astronomical Union describes them as more brilliant than a planet in the night sky. The minimum threshold to be considered a fireball is brighter than the absolute visual magnitude of -4 observed from a distance of 100km. For example, a meteor must be brighter than Venus observed in the morning or evening sky to be classified as a fireball.
Bolides
Bolides are at the top of the meteor hierarchy. They are more massive and brighter than fireballs. The largest are called “superbolides” and can be so massive they are considered natural hazards, a danger to the community. They often come to their end as an explosion in the atmosphere as they streak across the sky at a high velocity, over 40 miles a second. An example would be the house-sized superbolide that exploded over Chelyabinsk, Russia, in 2013. The explosion was comparable to the energy of 440,000 tons of TNT shattering windows in a 200-square-mile radius and, at its peak, emitting light 30 times brighter than the Sun. All resulted in over 1600 residents being sent to the hospital, mostly from broken glass.
Do Shooting Stars Hit The Earth?
A very small percentage of shooting stars will ever land on or impact the surface of the Earth. As explained earlier in this article, entering the Earth’s atmosphere is extremely hostile and will incinerate most everything. The meteors of asteroid origin, about 5% of all shooting stars, make up 86% of all the meteorite falls on earth. Their content is of a much more durable composition than the other 95% of shooting stars which originate from comet materials producing meteor showers. The meteor’s size, speed, and angle are also big factors in a successful impact.
According to the American Meteor Society, there are only up to 50 meteorite events hitting the Earth’s surface each day. Of these, 2 to 12 will be in populated regions where someone could observe and discover meteorite material. All the other impacts will happen over the oceans and uninhabited parts of the world. One meteorite fall can be anticipated to happen in every square mile of the Earth’s surface once every 20,000 years.
Rarely will there be a larger event deemed as an impact that creates a crater such as we see on the Moon, but they do and have happened. The Earth Impact Database, established in 1955 and operated by the Planetary and Space Science Center at the University of New Brunswick, keeps track of confirmed impact structures on Earth. As of 2023, they have confirmed 190 impact sites worldwide, stretching back millions of years. There are other suspected sites in the world that have not been scientifically backed by supporting evidence or passed the criteria required by the EID standards.
What Are Shooting Stars Made Of?
Shooting stars, or meteors, are mostly made of iron, nickel, and silicates (silicon and oxygen -the major components forming rock). There are different types
depending on the ratio of chemicals.
- Stony Meteors: Composition is mainly silicate with small amounts of metals.
- Stony-Iron Meteors: Close to equal amounts of silicate and metal.
- Iron Meteors: Close to 100% metal composition.
Meteors with high metallic content have a better chance of making it to the surface and becoming a meteorite. They handle the intense heat better than the higher silicate (rock) compositions.
The mostly silicate (rock) composition meteors tend to burn up and not make the title of meteorite. But, some do, as other factors, such as speed, size, and trajectory, play a role.
What Color Are Shooting Stars?
Shooting stars can appear in different colors. What they are made of will influence how they look in the sky. Once in the atmosphere, the high temperatures begin to vaporize chemicals within the meteor. Each chemical absorbs different color wavelengths of light in the visible spectrum, influencing how the energy emitted appears. The trajectory and velocity of the meteor will also affect how intense or bright the colors will be.
For example, a green-colored shooting star would suggest it has a higher chemical content of magnesium.
- Nitrogen/Oxygen – illuminates hues of red
- Iron – illuminates hues of yellow
- Calcium – illuminates hues of violet/purple
- Sodium – illuminates hues of orange
- Magnesium – illuminates hues of light blue to green
- Copper – illuminates hues of blue
How Often Are There Shooting Stars?
Every hour, day and night, tiny bits of dust and small particles enter the Earth’s atmosphere. The majority of these are called “sporadic” meteors. They can range between 2-5 per hour in any part of the sky. Robert Lunsford of the International Meteor Organization described this process as material hitting the Earth’s “front windshield.”
According to Nasa, Scientists estimate that 48.5 tons of meteoric material land on Earth daily. The American Meteor Society explains on its page, “Several thousand meteors of the fireball magnitude occur in the Earth’s atmosphere daily. The vast majority of these occur over the oceans and uninhabited regions, and a good many are masked by daylight.” Considering most never make it to land, that is a lot of shooting stars.
I ran a Fireball Report within the American Meteor Society’s “Report a Fireball” section which included all countries for the entire year of 2022. The results were 39,554 fireball sightings reported to their site. These were meteors people actually observed and took the time to report to the AMS.
There are times when shooting stars can be anticipated, much like a holiday event on our calendar. These are called meteor showers; we will discuss this in greater detail next.
Meteor Showers
Meteor showers are when Earth encounters many meteoroids at one time. It happens as the Earth crosses through the debris trail left behind by a comet or asteroid.
Comets, like Earth, orbit our Sun. As they get closer to the Sun, their icy surface breaks up, releasing a trail of dust and bits of rock scattered along the comet’s path. Then, at some point, as Earth makes its trip around the Sun, its orbit crosses through the field of debris left behind by the comet.
Since Earth’s orbit will repeatedly cross these same debris fields, we can determine when we will experience these annual meteor showers.
There are several different showers throughout the year. All are named after a constellation visible in that part of the sky from which the meteors appear to originate. This area is called the radiant point. Locating the constellation and radiant point is a great way to know where to keep watch for the upcoming celestial fireworks.
For example, the Leonids is named after the constellation Leo. The Leonid meteors appear to be coming from the constellation, when in fact, they are nowhere near the actual stars, but the Earth is moving through the debris field left behind by the Comet Temple-Tuttle. This is an optical illusion.
The meteors’ tails all appear to be pointing back to the same part of the sky, the radiant point. It is because all the meteors are coming toward us from the same angle, and the closer they come, they appear to be moving farther apart. If you have ever driven on the road in a snowstorm, you would have experienced this same illusion as the snowflakes appear to come from a narrow point further ahead, only to spread out as they approach the vehicle’s windshield.
Observing Tips
The best time to view these celestial fireworks can vary each year by a day or two. Some years will be better than others due to the phase of the Moon. The new Moon is best for observing with its dark skies, while the full Moon’s light makes it more challenging to see the smaller, fainter shooting stars. Check peak activity times each year for the best viewing.
Find a location as far away from light pollution as possible. The darker the better. If you are living in a city, consider traveling outside of city limits away from the bright lights.
When planning to view a meteor shower, wear warm clothes as the air can get chilled in late night hours, even during summer months. Bring hot beverages to stay hydrated. Take a folding chair that can lean back comfortably to observe the skies. A red flashlight will also help if you need to view your phone to cut down on light sources. It is best to watch with the naked eye only. Binoculars or telescopes will limit your field of view. A phone app which maps the night sky can help locate the constellations, so you will know where to look.
Major Meteor Showers | Approximate Dates of Appearance
- Quadrantids – Late December thru early January | Up to 110 meteors/hr
- April Lyrids – Mid to Late April | Up to 18 meteors/hr
- Eta Aquarids – Mid April thru Late May | Up to 50 meteors/hr
- Draconids – Early October | Up to 10 meteors/hr
- Perseids – Mid July thru Late August | Up to 100 meteors/hr
- Orionids – Early October thru Early November | Up to 20 meteors/hr
- Taurids – Early September thru late November | 5 meteors/hr
- Leonids – Early thru late November | Up to 10 meteors/hr
- Geminids – Early thru late December | Up to 150 meteors/hr
**For this years meteor schedule check out our Meteor Shower Info article:
12 Meteor Showers to Stay Up Late for in 2023
Shooting Stars In History
Shooting stars have been occurring since before the human race first opened its eyes. The ancient civilizations turned to myths and symbolism as a way to explain the unexplainable.
Falling stars were considered omens of good or bad events to come. They appeared from where their gods were known to reside and looked over their earthly domain. These are the origins of wishing on falling stars and asking for guidance and favor. Meteorites found on the ground were also thought to be gifts cast down from the angels.
An example of how the ancients perceived celestial events would be the martyrdom of an early deacon of Rome, Laurentius, on Aug. 10, 258 AD. Shortly after his execution, The Perseid meteor shower entered into peak activity. The locals believed the shooting stars to be the tears of deacon Laurentius, adding to his lore. Who at a later time would become St. Lawrence. To this day, The Perseid meteor shower is referenced by some as the “Tears of St. Lawrence”.
Conclusion
Shooting stars are spectacular events, reminding us there is so much out beyond our home here on Earth. Don’t forget to look up at night. You may catch a glimpse of something wonderful.
