Meteors light up our night sky, transforming space debris into dazzling displays. These cosmic streaks originate from and asteroids, becoming visible as they burn up in Earth's atmosphere at incredible speeds.
showers occur when Earth passes through debris streams, creating predictable annual events. Sporadic meteors, on the other hand, appear randomly from various sources. Both types offer unique insights into the composition of our solar system.
Meteors
Formation and visibility of meteors
Meteors form from small pieces of space debris (grain of sand size) usually originating from comets or asteroids
Comets approaching the Sun heat up and release dust and debris which continues to follow the comet's orbit forming a
Asteroids can also contribute to streams through collisions or fragmentation
Meteors become visible when entering Earth's atmosphere at high speeds (11-72 km/s) causing friction
Friction heats up the causing it to glow and create a visible streak of light in the night sky
Most meteors are small (sand grain size) but larger meteors called fireballs or bolides can be brighter than Venus and visible during the day
The process of a meteor burning up in the atmosphere is called
Causes and features of meteor showers
Meteor showers occur when Earth passes through a meteoroid stream left behind by comets or asteroids
Showers are named after the constellation they appear to radiate from (, )
Occur on the same dates each year when Earth's orbit intersects the meteoroid stream
Predictable annual events with peak activity lasting a few days and varying hourly meteor rates
Features of meteor showers include:
Meteors appearing to radiate from a single point in the sky called the
Similar velocities and compositions among meteors in a shower as they originate from the same parent body
Shower meteors are often brighter than sporadic meteors due to higher relative velocities
The is used to measure the intensity of a
Sporadic meteors vs shower meteors
Sporadic meteors:
Originate from various sources like asteroids or remnants of old dispersed meteoroid streams
Have random orbits and can appear from any direction in the sky
Tend to be slower (20-30 km/s) and less bright than shower meteors
Vary in composition depending on source but often include a mix of stony and metallic materials
Shower meteors:
Originate from a specific parent body usually a comet or asteroid
Follow the orbit of their parent body resulting in a predictable radiant and annual occurrence
Have higher velocities (40-60 km/s) than sporadic meteors due to their orbital geometry relative to Earth
More uniform composition within a shower reflecting the composition of the parent body
Perseids rich in volatile materials (ice, dust) as they originate from comet 109P/Swift-Tuttle
Geminids have a higher percentage of rocky material originating from asteroid 3200 Phaethon
Meteor phenomena
Some meteors leave behind a glowing trail called a
Meteor trains can persist for several seconds to minutes after the meteor has passed
Composed of ionized gases and can sometimes be visible to the naked eye
Key Terms to Review (21)
Ablation: Ablation is the process by which the surface of a material is removed through vaporization, chipping, or other erosive processes. In the context of meteors and meteorites, ablation refers to the removal of material from the surface of a meteoroid or meteor as it passes through the Earth's atmosphere.
Bolide: A bolide is a type of large, exceptionally bright meteor that often explodes in the upper atmosphere, producing a flash of light and occasionally fragmented meteorites reaching the ground. Bolides are distinguished from regular meteors by their greater brightness and more dramatic visual effects.
Chondrite: Chondrites are the most common type of meteorite, making up approximately 86% of all meteorites that fall to Earth. They are stony meteorites that have not been significantly melted or differentiated, preserving the original components of the early solar system.
Comet Halley: Comet Halley, also known as Halley's Comet, is a periodic comet visible from Earth every 75–76 years. It is one of the most well-known and bright comets, with its last appearance in 1986 and next expected in 2061.
Comets: Comets are icy celestial bodies that orbit the Sun and exhibit a visible atmosphere or coma and sometimes a tail when they come close to the Sun. They originate from the outer regions of the Solar System, primarily the Kuiper Belt and Oort Cloud.
Fireball: A fireball is an exceptionally bright meteor that appears to be larger and brighter than a typical shooting star. It is a very luminous meteor, often with a trail, that can be seen over a wide geographic area as it passes through the Earth's atmosphere.
Geminids: The Geminids are one of the most prominent and reliable annual meteor showers, known for their bright, slow-moving meteors. They are associated with the debris left behind by the asteroid 3200 Phaethon, which crosses the Earth's orbit and interacts with the planet's atmosphere, creating this spectacular celestial display.
Iron Meteorite: An iron meteorite is a type of meteorite that is composed primarily of iron, with smaller amounts of other metals such as nickel. These meteorites are some of the rarest and most valuable types of meteorites, as they provide a glimpse into the composition of the Earth's core and the formation of our solar system.
Leonids: The Leonids are a prolific meteor shower that occurs annually in mid-November. They are named after the constellation Leo, as the meteors appear to radiate from that region of the sky. The Leonids are associated with the comet Tempel-Tuttle, which leaves behind a trail of debris that Earth passes through each year, causing the meteor shower.
Martian meteorites: Martian meteorites are fragments of rock ejected from the surface of Mars that have landed on Earth. They provide valuable insights into the geological history and composition of Mars.
Meteor: A meteor is a streak of light produced when a meteoroid enters Earth's atmosphere and vaporizes due to friction with air molecules. Often called 'shooting stars,' they are typically very brief in duration.
Meteor: A meteor is a space rock or piece of debris that burns up as it passes through Earth's atmosphere, creating a visible streak of light in the night sky. Meteors are closely related to the topics of 14.1 Meteors and 14.2 Meteorites: Stones from Heaven, as they are the precursors to the physical objects that reach the Earth's surface, known as meteorites.
Meteor shower: A meteor shower is an event where numerous meteors are observed to radiate from a single point in the night sky. These meteors are caused by streams of cosmic debris entering Earth's atmosphere at extremely high speeds.
Meteor Shower: A meteor shower is a celestial event in which a number of meteors or shooting stars appear to radiate from a single point in the night sky. These meteors are caused by streams of cosmic debris known as meteoroids entering Earth's atmosphere at high speed and burning up, creating temporary trails of light we observe as meteors.
Meteor Train: A meteor train is a glowing trail of ionized gas that can be observed in the sky following the passage of a bright meteor. This ionized gas is created by the intense heat and pressure generated as the meteor rapidly travels through the Earth's atmosphere.
Meteorite: A meteorite is a piece of rock or metal from space that has survived passage through the Earth's atmosphere and landed on the surface of a planet or moon. Meteorites are closely related to the topics of 14.1 Meteors and 14.2 Meteorites: Stones from Heaven, as they are the remnants of objects that have entered the Earth's atmosphere.
Meteoroid: A meteoroid is a small rocky or metallic object that orbits the Sun, typically ranging in size from a grain of sand to a boulder. Meteoroids become meteors when they enter a planet's atmosphere and burn up, creating a visible streak of light in the sky.
Meteoroid Stream: A meteoroid stream is a collection of small rocky and metallic objects orbiting the Sun, often associated with a parent comet. These streams can produce regular meteor showers when the Earth passes through them, as the individual meteoroids burn up in the atmosphere, creating the visible shooting stars.
Perseids: The Perseids are a prolific meteor shower that occur annually in the month of August. They are named after the constellation Perseus, from which the meteors appear to radiate. The Perseids are one of the most well-known and widely observed meteor showers, known for their high rates of activity and the possibility of seeing bright, colorful meteors or 'shooting stars'.
Radiant: The radiant is the point in the sky from which a meteor shower appears to originate. It is the location in the celestial sphere where the parallel paths of the meteors in a shower seem to converge, even though the meteors are actually traveling independently through space.
Zenith Hourly Rate: The zenith hourly rate, also known as the zenithal hourly rate (ZHR), is a measure used in the study of meteors to quantify the number of meteors that can be observed in a given hour when the radiant point of the meteor shower is directly overhead. It provides a standardized way to compare the activity of different meteor showers.