The above real-time trace is updated every 60 seconds and shows meteors detected over the presceding two minute period.
Time is shown as Universal Coordinated Time (UTC) which is an intenational time standard equivalent to GMT. This avoids regional confusion with local time zones.
"This Hour" is the number of counts since the beginning of the hour. "Prev Hour" is the number of counts in the last full hour. "PHR (15 min)" is the "present hourly rate" based on a 15 minute sample.
The graph shows hourly counts throughout the last 24 hour period. Click on graph to see larger image.
Meteors Last 24 hours (Click for larger image)
A meteor occurs when a meteoroid (comet debris or asteroid fragment) strikes Earth’s atmosphere at high speed. Intense heat is created by the compression of the air ahead of the meteoroid, which usually causes the object to burn up in the atmosphere, creating the white “shooting star” that we are all familiar with. This process also ionises the atmosphere along the trail, making it possible to reflect radio waves.
Utilising a high powered VHF radar, we are able to detect reflected waves from the ionisation trail. Because the meteor is moving very fast, the reflected signal is also shifted in frequency by a small amount according to its speed. This "Doppler" shifted reflection can also be translated into audio and is heard as an audible ping by the station operator.
You can see a live capture every sixty seconds from one of our screens as shown above in real time. This trace shows the most recent ~90 second period and is updated every minute.
During a major meteor shower this image will be full of meteor traces, but general activity can be seen most of the time, usually peaking in the early hours of the morning when Earth's orbit takes us directly into any space debris . It's surprising how many meteor events are happening every single day.
Our system automatically analyses detected signals to determine if it was a meteor or other interference. If a meteor is detected it is counted for statistical analysis. For further research we can analyse a meteor, from detailed charts in order to determine other information such as relative size, velocity, or if a meteor is sporadic or belongs to a particular meteor shower for instance. We are researching and improving our methods of detection all the time.
Typical Meteor Strike
Here you can see a typical meteor event. The trace starts high in frequency (towards right of graph) and rapidly drops to the radar carrier frequency as the meteor decelerates in the atmosphere, increasing in strength (ionisation) as it burns up. This creates this typical triangular shape you can see here. The width, height and shape tell us a lot about the meteor event. The blue region is the baseline atmospheric noise.
Meteor Showers in
- Quadrantids - January 3rd
- Lyrids - April 21/22
- Eta Aquarids - May 5/6th
- Perseids - August 12th
- Orionids - October 21st
- Leonids - November 17th
- Geminids - December 13th
These are the main annual meteor events visible with the naked eye. There are many smaller meteor showers throughout the year.