Astrophysicists from Trinity are gearing up to map the Perseid meteor shower from the Irish Low-Frequency Array (I-LOFAR) radio telescope complex in Birr Castle, Co. Offaly this weekend.
Saturday night – 12th August – is due to have the highest level of meteor activity with one meteor expected to be visible each minute, and the public can watch events unfold and count the shooting stars with their own eyes.
Meteors are small pieces of rock that have broken away from asteroids or comets due to collisions or extreme heating caused by their tremendous velocities. The small rocks enter Earth’s atmosphere and the resulting drag or air resistance of the air particles leads to further heating. This heating produces a huge glow that we can observe from the ground.
A “shower” of meteors is caused when a comet passes especially close to the Sun & Earth, which induces a large amount of heating and break-up. In the case of the Perseids, Earth is passing through the dust and debris left behind the comet Swift–Tuttle. The shower is best seen during early-mid August each year. This year the Perseids will be most active on the nights of the 11th-12th & 12th-13th August and can be seen with the naked eye (visibility will be improved by getting as far away from light pollution as possible).
How are the I-LOFAR astrophysicists going to detect the meteors and what will they learn?
The team at I-LOFAR is hoping to observe the Perseid Shower using two different methods:
- Using radio antennae to detect reflections of military/aeronautical radar off the plasma trail of each meteor (the “passive radar method”). I-LOFAR will be trying to observe the reflection from a French radar used to monitor satellite orbits, called GRAVES, at 145 MHz
- Measuring direct emission from plasma in the tails below 60 MHz as was done here by the Long Wavelength Array
From these observations, the I-LOFAR team hopes to determine the number of meteors per minute, how fast they were travelling, from where they originated, and where they were going in the plane of the sky.
You can read more about I-LOFAR and keep an eye on the results of this weekend’s experiments here.