Dominic Ford, Editor
From the Meteor Showers feed
The γ-Normid meteor shower will be active from 25 February to 28 March, producing its peak rate of meteors around 14 March.
Over this period, there will be a chance of seeing γ-Normid meteors from anywhere where the shower's radiant point – in the constellation Norma – is above the horizon. Unfortunately, however, it will not be visible from Fairfield at any time, since its radiant point never rises above the horizon.
The radiant of the shower
Meteor showers arise when the Earth passes through streams of debris left in the wake of comets and asteroids. Over time, these pieces of grit-like debris distribute themselves along the length of the parent object's orbit around the solar system.
Shooting stars are seen whenever one of these pieces of debris collides with the Earth, typically burning up at an altitude of around 70 to 100 km, upon impact with the upper atmosphere.
On certain days of the year, the Earth's orbit passes through particularly dense streams, associated with comets or asteroids which have vented particularly large amounts of solid material to space, and this gives rise to an annual meteor shower. The shower recurs on an annual basis, whenever the Earth passes the particular point in its orbit where it crosses the stream of material.
All of the meteors associated with any particular meteor shower appear to radiate outwards from a common point on the sky, which points back in the direction from which their orbital motion brought them.
This is because all the meteors are travelling in almost exactly the same direction when they cross the Earth's orbit, owing to having very similar orbits to the parent object they came from. They strike the Earth from almost exactly the same direction, and at the same speed.
By determining the position of this radiant point on the sky, it is possible to work out the orbit of the stream giving rise to any particular meteor shower. It is sometimes even be possible to identify the particular body responsible for creating the debris stream, if there is a known comet or asteroid with a very similar orbit.
The radiant of the γ-Normid meteor shower is at around right ascension 15h50m, declination 50°S, as shown by the green circle on the planetarium above.
To see the most meteors, the best place to look is not directly at the radiant itself, but at any dark patch of sky which is around 30–40° away from it. It is at around this distance from the radiant that the most meteors will be seen.?>
|The sky on 14 March 2014|
13 days old
All times shown in EDT.
The International Meteor Organisation's List of Meteor Showers.
© Jacek Halicki 2016. Perseid meteor seen in 2016 from Poland.