Recent Occurrence Of Meteor Shower
Recent occurrence of Meteor Shower
On most nights, an attentive observer might expect to see between two and ten meteors per hour, depending on the season and time: more meteors are seen in the autumn, and rates are highest as dawn approaches. This activity pattern for random, background sporadic meteors is enhanced at certain times of year by the occurrence of meteor showers.
Meteor showers occur at the same time each year, as Earth in its annual orbit around the Sun ploughs through streams of debris. About twenty prominent showers are recognised, varying in activity from a handful of meteors per hour, to one per minute or more. Some can even, on occasion, produce storms in which the sky is filled with meteors for a short time.
Meteors produced by the general dust spread along Earth's orbit are called sporadics.
MeteorMost of the regular, annual showers are produced by small debris, meteoroids - typically a couple of millimetres in diameter, shed by comets when close to the Sun. The debris continues in its own orbit around the Sun, and successive returns of the parent comet to the inner solar system feed more material into the stream. Halley's Comet, for example, has laid down an extensive stream through which Earth runs twice each year, in May and October.
Since they share a common orbital motion through space, meteoroids in a given stream will also enter Earth's atmosphere on parallel trajectories. As they burn up at heights of around 100 kilometres (60 miles), the resulting meteors appear to emanate away from single small area of sky, known as the radiant. The radiant effect is a result of perspective.
The radiant indicates the intersection between Earth's orbit and that of the debris stream. Observers' counts give a measure of the particle distribution in a stream.
Each stream is different. Some, like August's Perseids, have a fairly even distribution of material, and show a similar activity pattern year after year. Others, like the November Leonids
On most nights, an attentive observer might expect to see between two and ten meteors per hour, depending on the season and time: more meteors are seen in the autumn, and rates are highest as dawn approaches. This activity pattern for random, background sporadic meteors is enhanced at certain times of year by the occurrence of meteor showers.
Meteor showers occur at the same time each year, as Earth in its annual orbit around the Sun ploughs through streams of debris. About twenty prominent showers are recognised, varying in activity from a handful of meteors per hour, to one per minute or more. Some can even, on occasion, produce storms in which the sky is filled with meteors for a short time.
Meteors produced by the general dust spread along Earth's orbit are called sporadics.
MeteorMost of the regular, annual showers are produced by small debris, meteoroids - typically a couple of millimetres in diameter, shed by comets when close to the Sun. The debris continues in its own orbit around the Sun, and successive returns of the parent comet to the inner solar system feed more material into the stream. Halley's Comet, for example, has laid down an extensive stream through which Earth runs twice each year, in May and October.
Since they share a common orbital motion through space, meteoroids in a given stream will also enter Earth's atmosphere on parallel trajectories. As they burn up at heights of around 100 kilometres (60 miles), the resulting meteors appear to emanate away from single small area of sky, known as the radiant. The radiant effect is a result of perspective.
The radiant indicates the intersection between Earth's orbit and that of the debris stream. Observers' counts give a measure of the particle distribution in a stream.
Each stream is different. Some, like August's Perseids, have a fairly even distribution of material, and show a similar activity pattern year after year. Others, like the November Leonids