When a meteor strikes Earth’s atmosphere it decelerates rapidly. The friction created by the air causes the meteor to burn up at extremely high temperatures creating the white “shooting star” that we are all familiar with. This process also ionises the air along the trail making it possible to reflect radio waves.
Utilising a high powered VHF radar signal sent into the sky, we are able to detect reflected waves from these ionisation trails. Because the meteor is moving, the reflected signal is shifted in frequency from the original, by an amount according to it’s speed. This shift is also heard as an audible ping by the station operator.
Our system translates the reflected wave into three main parameters - Amplitude (strength), Frequency shift (Doppler shift) and decay time. This allows us to determine the relative size of the meteor strike (vertical scale) and the relative approximate speed and deceleration (amount of shift and width of the trace).
You can see the output from our system above in real time (approximately 1 minute delay on the Internet). During a meteor shower this trace will be full of strike traces, but it is also surprising how many meteors are striking Earth’s atmosphere all of the time.
Originally posted by woogleuk
reply to post by RhinestoneCowboy
It's called the Geminids meteor shower, it peaks today/tonight, I'm about to head out with the camera, expect 30 - 100 per hour, maybe more if there is a burst.
edit on 13/12/12 by woogleuk because: (no reason given)